This post is not a summary of all the actions with unintended consequences that step-by-step drew the U.S. into the Asia-Pacific War. Perhaps the entire history of Japanese-U.S. relations has been marked by these. At one level it is not surprising given cultural differences. Compared to Japan, the United States was an infant country without substantive history, traditions, and a society that most readily ignored boundaries and traditions that did not seem to suit our future. The U.S. was a cauldron of immigrants, settlers and pioneers – all from somewhere else – completely committed to the idea that there were no limits. Japan was the antithesis of that. Steeped in tradition, social class, racial purity, a nation apart from all other nations – and so many other factors. Japan, its culture and language, were subtle, nuanced and intentionally vague at times. The American psyche lacked all those things. The difference can be seen in the U.S Department of State’s basic view towards Japan: they were not an honest dialogue partner in that their words “did not mean what they said” – a trait sometimes maddening to even the Japanese. If diplomacy is the art of words to reach mutual agreements, the relationship was bound to face hurdles. None more so the Japanese move into Southern Indochina and U.S. reaction to that move.

One of the intriguing tales of the summer of 1941 was the role of the Foreign Funds Control Committee (FFCC). After the July 1941 asset freeze, the FFCC was created and composed of representatives from State, Treasury, and Justice. It was created to decide whether frozen Japanese funds could be released to pay for licensed exports. Although approved licenses already existed for items as required by the 1940 Export Control Act (including oil), funds had to be released for transactions to occur. The FFCC became the final control point, bottleneck, obstruction – take your pick – for the commodity to be transhipped to Japan.

As Assistant Secretary of State for Economic Affairs, Dean Acheson was the State Department’s principal representative on the FFCC and the member most concerned with the strategic implications of fund releases so that such releases were consistent with policy and plans. Depending on the historian’s point of view, he fulfilled his role in accordance with the directions and desires of State and the President, or he was the rogue bureaucrat responsible for pushing Japan to attack the U.S., or he was a de facto operative of the White House acting as directed in the moment by the President, or was part of a governmental-industrial conspiracy to accelerate the U.S. to war with Japan and with Germany. 

The FFCC was charged with determining whether frozen funds could be released to pay for licensed exports. This structure preserved formal flexibility and allowed the administration to claim that economic pressure could be adjusted in response to Japanese behavior. In practice, however, the committee became the instrument through which flexibility slowly disappeared.

But it was Acheson’s interpretation and execution of the financial freeze that effectively converted an ambiguous measure into a de facto total embargo.

Intended Ambiguity

Roosevelt and Secretary of State Cordell Hull had deliberately left the asset freeze ambiguous, preserving room for maneuver. They put the FFCC in place with the State Department’s representative, Acheson, with essential veto power over the release of assets for approved licenses – even ones already approved before the establishment of the FFCC. Acheson approached the asset freeze with a clear premise: Japan’s actions had fundamentally altered the strategic situation and partial economic accommodation would undermine U.S. credibility as to the seriousness of Japan’s actions in Indochina most immediately and China in general. But it was Acheson’s interpretation and execution of the financial freeze that effectively converted an ambiguous measure into a de facto total embargo.

The practical effect of the FFCC’s decisions was swift and unmistakable. Japanese oil imports from the United States ceased almost entirely. While the administration never formally declared an oil embargo in July 1941, Japanese officials and American observers alike understood that this was its substance. Japan faced the prospect of exhausting its fuel reserves within eighteen to twenty-four months or sooner if military operations expanded.

Historians often describe this moment as one in which bureaucratic implementation became strategic policy. Roosevelt and Secretary of State Cordell Hull had deliberately left the asset freeze ambiguous, preserving room for maneuver. Acheson’s strict enforcement closed that space. Importantly, neither Roosevelt nor Hull reversed or overruled the FFCC’s decisions once their effects became clear. This silence has led most scholars to conclude that Acheson’s actions, while assertive, aligned with the administration’s evolving judgment that Japan must be confronted decisively.

The central historiographical debate concerns Acheson’s intent. Did he deliberately seek confrontation, or did he accept it as just the risk inherent in enforcing policy? There is little evidence that he desired conflict for its own sake but he was noted for believing Hull’s policy to date had been continually ineffective – and yet Hull appointed him to the FFCC.

More critical interpretations suggest that Acheson underestimated the degree to which economic strangulation would empower hardliners in Tokyo and eliminate remaining diplomatic leverage (if there were any by this point). From this perspective, the FFCC’s rigidity foreclosed possibilities that Ambassador Grew and Japanese moderates still hoped to explore. Yet even these critics tend to frame Acheson’s actions as firmness, not reckless adventurism or rogue action.

What is broadly agreed upon is that Acheson understood the stakes. He recognized that denying oil would be perceived by Japan as an existential threat. His willingness to proceed reflects a judgment, shared by Hull and Roosevelt, that deterrence required clarity, even at the risk of war.

Strategic Deadlock

From Tokyo’s perspective, the FFCC’s decisions confirmed the worst suspicions of the Japanese Army. Diplomats reported repeatedly that licensed exports meant nothing if funds could not be released. The oil cutoff became central to Japanese strategic calculations, reinforcing arguments that the United States sought to force Japan into submission without regard for its survival.

This perception mattered more than American legal distinctions. Japanese leaders concluded that time was running out and that negotiation under embargo conditions could only produce humiliation or surrender. The FFCC thus played a direct role in accelerating Japan’s decision-making timetable, but it did not dictate the final choice for war. That choice was Japan’s.

By late 1941, both Japan and the United States viewed their positions as defensive and morally justified. Japan believed economic strangulation threatened national survival and left only force as an option. The United States believed failure to draw a firm line would invite endless expansion and undermine international order. The tragic irony is that each side’s attempt to avoid future disaster accelerated immediate catastrophe.

The road to Pearl Harbor was thus paved not by a single decision, but by a decade of incremental actions, misconceptions, and narrowing choices. Japan’s pattern of faits accomplis eroded trust; America’s gradual escalation of economic pressure collapsed the space for compromise. In that sense, the final crisis of 1941 was less a sudden rupture than the inevitable culmination of a long, unresolved confrontation between power, principle, and fear.

Image credit: various photographs from Naval Aviation Museum, National World War II Museum, and US Navy Archive

Between July 1940 and the Summer of 1941, the war in China continued. The military situation in China was characterized by a transition into a brutal war of attrition against Japanese occupation, alongside a significant internal breakdown in the alliance between Chinese Communist and Nationalist forces. Among major actions was the “Hundred Regiments Offensive” (Aug 1940 to Jan 1941). It was the largest Communist-led offensive of the war, involving roughly 400,000 troops. It targeted Japanese-held infrastructure, specifically railroads and mines, in northern China to disrupt supply lines. In retaliation, the Japanese initiated the “Three Alls” policy: kill all, burn all, loot all. It was a scorched-earth policy, leading to widespread massacres and the destruction of thousands of villages.

Meanwhile to the south, the Nationalist Army enjoyed some victories and endured some losses. It was a clear implementation of the “war of attrition” policy against the Japanese.

During this period the U.S. continued to provide supplies via the Burma Road and began formalizing military aid through the Lend-Lease program, which included the procurement of P-40 aircraft for the American Volunteer Group, known as the “Flying Tigers.”

The Turning Point

In July 1941 Japan moved into Southern Indochina. This was the “bridge too far.” By mid-1941, Japan’s strategic position had become increasingly precarious. The war in China showed no sign of resolution, Japan’s economy was under strain, and dependence on foreign, especially American, oil had become acute. The occupation of southern Indochina in July 1941 represented a decisive escalation driven by both necessity and ambition, as Japanese leaders concluded that time was working against them.

The immediate rationale lay in Japan’s southern expansion strategy (Nanshin-ron), which had become the strategic plan after the defeat at Nomonhan at the hands of the Soviet Union. Southern Indochina offered strategic airfields and naval bases particularly around Saigon and Cam Ranh Bay. This placed Japan within striking distance of British Malaya, Singapore, and the Dutch East Indies, the latter being Japan’s most coveted objective due to its vast oil reserves. Control of southern Indochina would serve as a springboard for future operations, not merely a continuation of the China war.

Japan also viewed the move as defensive and deterrent. Japanese planners feared that continued U.S. and British pressure would eventually choke off vital imports. Occupying southern Indochina was intended to secure strategic depth, signal resolve to Western powers, and strengthen Japan’s negotiating position.  Coercion had proved successful before and so Japan stayed with what worked.

Japanese leaders still hoped to avoid war with the United States but the nationalist and military believed that a show of strength would compel Washington to accept Japan’s dominance in East Asia or at least negotiate a settlement recognizing Japan’s “special position.” As with earlier expansions, Tokyo framed the occupation as temporary and stabilizing, carried out with Vichy French acquiescence rather than outright conquest.

Unlike the occupation of northern Indochina in 1940, which could be justified as cutting Chinese supply lines, the move south had no plausible defensive rationale. It directly threatened Western colonial holdings and, crucially, placed Japanese forces astride the sea lanes connecting the United States, Britain, and Southeast Asia. For American policymakers, southern Indochina marked the point at which Japanese intentions could no longer be interpreted as limited or negotiable. Their goal of regional domination, far beyond trade, was unmistakable. All signs were that Japan was preparing for an offensive war – which was exactly the Nanshin-ron strategy.

The U.S. Internal Debate

The Japanese move triggered an intense but brief debate within the Roosevelt administration. The debate was brief because all the arguments had already been raised during earlier crises. Within the State Department, Cordell Hull concluded that Japan had crossed a qualitative threshold. While Hull had previously opposed measures such as an oil embargo on the basis that it might force Japan into a corner, he now accepted that failure to respond decisively would invite further expansion. Southern Indochina confirmed Hornbeck’s and others’ arguments that incremental pressure and diplomacy were never going to constrain Japan.

At the same time, Treasury Secretary Morgenthau and others argued that the United States had been subsidizing Japanese aggression through continued trade, especially petroleum exports. Morgenthau pressed for immediate financial measures that would cut off Japan’s access to dollars and strategic materials. President Roosevelt, who had long sought to balance deterrence with delay, now sided with the more forceful camp.  It was not because he sought war, but because he believed that credibility and long-term security required drawing a firm line. Southern Indochina convinced Roosevelt that ambiguity no longer served U.S. interests.

U.S. Actions and Their Consequences

In response, the United States took a series of actions that fundamentally altered the strategic environment. Two coordinated actions were put in place. In July 1941 the U.S. froze all Japanese financial assets in the United States. The funds were available when connected to a valid and approved export license. The 1940 Exports Control Act already required an export license for oil and oil products, but now companies and purchasing agents had to navigate the dual administrative processes. At no point did the U.S. formally announce an oil embargo, but a de facto embargo was enacted by these two administrative processes that could “slow roll” any license applications. These two actions effectively prevented Japan from purchasing American goods, including oil, as approvals became trapped in the bureaucracy of the two separate processes. That being said, Japan’s petroleum supply from the U.S. was effectively cut off. Given Japan’s heavy dependence on American oil, they viewed this as an existential threat.

Britain and the Netherlands soon imposed similar freezes, closing off alternative sources in Southeast Asia. Japan now faced the prospect of economic strangulation within a year if no resolution was reached. 

These measures were intended to force Japan back to the negotiating table. American leaders hoped that the severity of the response would compel Japan to halt further expansion and reconsider its position in China. Instead, the effect was the opposite: Japanese leaders increasingly concluded that only force could secure the resources Japan needed to survive and continue their military expansion.

The occupation of southern Indochina was Japan’s final major expansion before U.S. involvement in the Asia Pacific War. From their point of view it was driven by strategic desperation, resource insecurity, and overconfidence in coercive diplomacy. For the United States, it marked the moment when gradualism gave way to decisive economic action. The resulting asset freeze and effective oil cutoff were not intended as steps toward war, but they made war increasingly likely. 

Japanese leaders were nationalistic and supported the military. Their analysis of history was that it was only with military power and control that Japan’s future against western powers could be secured. And so for them they saw that peaceful options had run out. The irony is that for the previous four years, Japan had never taken a peaceful option but had always exercised the military option – and always via surprise attack and mobilization: Mukden, Nomonhan, and soon enough, Pearl Harbor.

The Japanese move into Southern Indochina was the irreversible hinge between diplomacy and conflict. It was the moment when both sides believed they were acting defensively, yet set in motion the final march toward Pearl Harbor. 

Image credit: various photographs from Naval Aviation Museum, National World War II Museum, and US Navy Archive

By June 1939 Japan was deeply entrenched in China with a military stalemate, the Chinese willing to fight a war of attrition, and there was no political settlement in sight. Japan had just suffered a major defeat at Nomonhan, though this was not fully appreciated in Washington at the time, and elements of Japanese leadership were increasingly suspicious of Western intentions. That same month the U.S. formally notified Japan it would terminate the 1911 Treaty of Commerce and Navigation, effective January 1940. This did not impose sanctions immediately but freed the U.S. legally to restrict trade later. The purpose of the actions was to signal displeasure with Japan’s conduct in China, create leverage without escalation, and preserve diplomatic ambiguity. It was not well received in Japan as they understood that beginning in January 1940 there would be no treaty in place that could limit trade restrictions. At the same time the State Department issued nonbinding requests to U.S. firms not to sell aircraft, aviation fuel or strategic materials to Japan. This reflected Hull’s belief that economic pressure should precede coercion, and coercion should precede war. This would come to be known as the “moral embargoes” and marked the first move from moral pressure towards economic leverage

French Indochina

A key reason China could continue fighting was that foreign supply routes remained open, especially the Burma Road and rail and port access through French Indochina, particularly via Haiphong into Yunnan Province.From Tokyo’s perspective, cutting these supply lines became essential. Japan was presented a strategic opportunity with the collapse of France to German forces in June 1940. As a consequence the Vichy regime replaced the French government. This left French colonial authorities isolated, under-resourced, and politically uncertain. To Japanese planners, Indochina now looked militarily weak and diplomatically unsupported and unlikely to receive British or American military support in the short term. To the Army, Navy, and politicians this created a low-risk window of opportunity.

Japan initially pursued its objectives through coercive diplomacy, not outright invasion. Japan demanded that Vichy France close supply routes to China, permit the Japanese to station inspectors at transportation junctions (and later military forces), and provide unfettered access to airfields in the North. Vichy France wanted to preserve sovereignty but lacked the military means to resist and so hoped that accommodation would prevent full occupation. Negotiations dragged on while Japan prepared militarily, a familiar pattern since Mukden.

Despite French promises, Japan believed that supplies were still leaking into China, French officials were unreliable, and only physical control could guarantee closure of routes. The Japanese Army argued that diplomatic assurances were meaningless without troops on the ground, reflecting the Army’s broader pattern of fait accompli strategy.

In September 1940, Japanese forces crossed into northern Indochina and occupied key airfields and rail lines. They clashed briefly with French colonial troops but soon enough all resistance collapsed. Shortly afterward a formal agreement legalized the Japanese presence while French administration remained nominally in place.  Japan was fine with leaving administration to the French because they had gained what they wanted: control of transport corridors and air bases from which to control supplies into China.

Japan limited itself initially to northern Indochina because the stated goal was cutting China’s supply lines and it allowed Japan to test Western reactions in an incremental way as it avoided directly threatening oil supplies.

To the international community, Japan deliberately framed this as a “temporary” measure, a defensive necessity and not an annexation. But while China was the immediate justification, larger strategic calculations were at work. After the defeat at Nomonhan, the Northern expansion against the USSR lost credibility and attention shifted south toward Southeast Asia. Indochina offered a stepping stone toward the Dutch East Indies with airfields within reach of British Malaya. Japan also believed a decisive move would demonstrate resolve to the point the U.S. and Britain would protest but would not fight or take any decisive action. Internally it provided prestige to the military and the government and was promoted at home. Japan calculated that in the short term Britain was fully engaged in a battle for its national life (the “Battle of Britain”) while the U.S. was still divided and formally neutral.

The U.S. response was as Japan expected: a strong diplomatic protest, limited export controls, but no other embargo action. All in all, this reinforced Japanese beliefs that incremental expansion would work.

Reaction with the U.S. Government

The U.S. response to Japan’s occupation of northern Indochina exposed deep internal divisions within the Roosevelt administration over how far and how fast to confront Japan. At the center of the debate was a shared recognition that Japan had crossed an important threshold, but no consensus on whether that threshold justified decisive economic retaliation or continued diplomatic caution.

Within the State Department, Secretary of State Cordell Hull favored a measured, incremental response. Hull believed Japan’s move was aggressive but still reversible and that premature, sweeping sanctions, especially on oil, risked provoking a war the United States was not yet prepared to fight. State Department officials continued to emphasize negotiation, the preservation of legal and moral principles (such as the Open Door in China), and the use of graduated economic pressure to influence Japanese decision-making. Hull and his advisers, especially Ambassador Grew, held out hope that divisions within Japan, particularly between civilian moderates and the military, could still be exploited diplomatically.

By contrast, Treasury Secretary Henry Morgenthau Jr., supported by some in the Interior and Navy Departments, argued that Japan’s occupation demonstrated that incremental pressure had failed; it had been applied for almost three years. This faction favored stronger economic sanctions, including tighter export controls and financial restrictions, to signal that further expansion would carry unacceptable costs. Morgenthau was particularly concerned that continued U.S. trade, especially in oil, gasoline, aviation fuel,  and scrap metal, was materially enabling Japanese aggression. President Franklin Roosevelt ultimately sided, for the moment, with Hull’s caution: the U.S. imposed new export controls and intensified diplomatic protests but stopped short of an oil embargo. The compromise reflected a broader strategic judgment that time was needed to strengthen U.S. defenses while keeping open the possibility, however slim, of restraining Japan without war.

Export Controls Act 

In July 1940 Congress passed the Export Controls Act in response to Japan’s move into northern French Indochina. At the core of the legislation was that the State Department gained authority to license or deny exports. Immediately restrictions were placed on aviation gasoline, high quality scrap iron and machine tools. The licensing process gave the State Department the ability to “approve” the request and then slow march the license through the administrative process where decisions were deliberately incremental and often reversed

The Departments of Treasury and Interior wanted stronger measures and more excluded items. Despite pressure from Treasury and some Navy officials, the administration deliberately excluded oil from the provisions of the 1940 Act. Petroleum exports continued, ordinary commercial goods remained largely unaffected, and financial transactions were not yet frozen. All this reflected Secretary Hull’s view that an oil embargo would be indistinguishable from a declaration of economic war. This marked a clear escalation in U.S. policy, but one carefully calibrated to apply pressure without forcing an immediate showdown.

Image credit: various photographs from Naval Aviation Museum, National World War II Museum, and US Navy Archive

In the summer of 1939 Japan was increasingly bogged down in combat with China. As you can see in the map below, Japan controlled not only Manchukuo (Manchuria) but swaths of Inner Mongolia and China. Importantly, Japan also controlled almost all major seaports facing the East and South China Sea. Manchukuo presented its own control issues, largely centered around rampant banditry, but all the other areas required the Kwantung Army (Imperial Japanese Army on the mainland) to provide occupation and policing forces in areas they had conquered. At the same time the Kwantung Army continued offensive operations in Northern China.

Notice that Japan also had an extensive border with the Soviet Union as well as a history of conflict with czarist Russia that extended some 60 years back in time including the 1904-1905 Russo-Japanese War which removed Russian presence in Manchuria and Korea. Russia lost the warm water ports in Darien and Port Arthur, access to the resources of Manchuria, and was often required to transport goods and resources via the Trans-Siberian Railway rather than via ship. In addition Russia was required to cede the lower half of Shanklin Island (just north of Japan). All of this fit into Japan’s “strategic buffer” concept keeping China and Russia/Soviet Union at “arm’s length” from the home islands.

The Nomonhan Incident

Also known as the Battles of Khalkhin Gol, the Nomonhan Incident was a major but undeclared border war fought between Imperial Japan and the Soviet Union’s Mongolian forces from May to September 1939. It occurred along the poorly defined frontier between Japanese-controlled Manchukuo and Soviet-aligned Mongolia. Though officially termed an “incident” by Japan to avoid acknowledging a formal war, the conflict involved tens of thousands of troops, armor, artillery, and aircraft, making it the largest land battle Japan fought before the Pacific War. The fighting ended in a decisive Soviet victory, delivering a shock to the Japanese military and reshaping Japan’s strategic direction on the eve of World War II.

The Background

At the root of the conflict was a disputed, ambiguous border. Japan claimed the boundary lay along the Khalkhin Gol (Halha River), while the Soviets and Mongolians insisted it lay several miles east. The area was remote, sparsely populated, and economically marginal but symbolically important as a test of sovereignty and power. It was also extremely remote from the Imperial Japanese Army (IJA) Staff and Ministry in Tokyo. All of this was simply ingredients of a toxic stew only awaiting the flame to start a boil. And the Kwantung Army was only too happy to ignite the flame.

The Kwantung Army had a well earned reputation for acting autonomously from Tokyo, initiating aggressive actions to force what it believed were the necessary political outcomes, and viewing itself as the vanguard of Japan’s continental destiny. This attitude led to the Mukden Incident (1931), the Marco Polo Bridge Incident (1937), and the quagmire of the Second Sino-Japanese War. By the summer of 1939 the IJA was already stretched thin, had terrible logistics support, and was lacking in combined arms capability – meaning tanks, artillery and ground support from aviation assets. Financially, Japan was stretched thin in trying to keep the IJA funded at the same time funding the Navy’s capital intensive shipbuilding efforts.

Nonetheless, by 1939 the bane of IJA’s existence – an independent, insubordinate junior officer corps believed that controlled escalation against the Soviets could secure Japan’s northern frontier, expand the strategic buffer or even open the door to expansion into resource-rich areas of Siberia. In the view of Japan, the majority of the peoples in Siberia and Mongolia were Asiatic and thus properly best served under the Imperial Protection of the Emperor. They did not bother to ask the people of those areas about their preference.

Northern Expansion Doctrine (Hokushin-ron)

Within Japan’s strategic debates, the Army strongly favored Hokushin-ron, the idea that Japan’s future lay in expanding northward against Russia rather than southward into Southeast Asia. This belief rested on overconfidence from victories in China, an underestimation of Soviet military modernization, and a deep seated anti-communism which was, at this time, being suppressed in the home islands. Nomonhan emerged from a belief that the Red Army could be tested, pressured, and defeated through limited engagement. It was less a grand strategy and more a tactical escalation.

In part it was also pushing back on the evolving southern expansion doctrine being proposed by the Imperial Japanese Navy (IJN) whose interest lay in the resource-rich Southwestern Pacific, especially the oil fields of Borneo, Malay and Java.

The local IJA commanders were confident that Japanese infantry superiority would compensate for weaknesses in armor and logistics. In addition, they believed that the Soviets would avoid a major escalation. The Kwantung Army assumed that a sharp, localized victory would strengthen Japan’s hand diplomatically and militarily.

The IJA horribly misread Soviet intentions. The Soviets retained the memory of the humiliating defeat by Japan of czarist Russia. It was a lingering shame that the Soviets would never let happen again. They were more than willing to fight. They also had superior tanks and artillery and a capacity for combined arms operations with their ground forces. Japan also failed to recognize that the Soviets had the same essential “strategic buffer” view as Japan. Mongolia as part of that buffer and the Soviets would respond decisively to any threat in that region.

Combat

In the period May–June 1939, the initial clashes involved cavalry and infantry skirmishes for small areas of land as well as an island in the middle of the border river. Japanese forces crossed into disputed territory, driving out Mongolian units. Early successes reinforced Japanese confidence.

In June, the Soviets appointed General Georgy Zhukov to command. Zhukov rose to prominence with his leadership at Nomonhan. He was a brilliant tactician and field commander later becoming the most prominent and successful Soviet military commander during World War II often credited as the key strategist behind major Eastern Front victories against Nazi Germany. He rose to the position as Chief of the General Staff and a Marshal of the Soviet Union, leading the defenses of Moscow, Leningrad, Stalingrad and commanding the final assault on Berlin. He was formidable. 

Long story, told short, Zhukov prepared a coordinated counteroffensive rather than piecemeal retaliation, amassing artillery, tanks, and aircraft supported by secure logistics/supply lines. In late August, Zhukov launched a classic double-envelopment, using tanks and mechanized infantry to encircle Japanese forces who lacked effective anti-tank weapons, were undersupplied, and relied on infantry assaults against armor. The result was catastrophic. Entire Japanese formations were destroyed or rendered combat-ineffective. It was a clear battlefield defeat involving some 20,000 Japanese casualties with the loss of experienced officers and elite units. Japan agreed to a ceasefire in September 1939, restoring the status quo but psychologically, the damage was done. It was the first unequivocal defeat suffered by Imperial Japan since the Meiji era.

Unintended Consequences

Nomonhan should have shattered Japanese assumptions – but it did not. Japan continued to believe that Japanese fighting spirit and bushido were enough to triumph and could overcome material inferiority and weak logistics. This would plague them all the way through 1945. They also continued to believe that wars could be tightly controlled and limited.

The defeat decisively undermined the Northern Expansion faction within the Army. After 1939 all plans for war against the Soviets were shelved, a defensive posture was adopted along the Manchurian frontier, and Japan avoided conflict with the Soviets for the remainder of WWII. This shift paved the way for Nanshin-ron (southern expansion), pushing Japan toward Southeast Asia and the Dutch East Indies’ oil. It was the path to confrontation with Western colonial powers. In this sense, Nomonhan helped set Japan on the road toward Pearl Harbor.

Perhaps the most profound unintended consequence was for the Soviet Union. Stalin gained confidence that Japan would not attack in the east and soon enough the two nations signed the Soviet–Japanese Neutrality Pact (1941) allowing Soviet divisions to later be transferred west to defend Moscow against Germany. The Nomonhan incident influenced the outcome of the European war, not just Asian geopolitics.

The Nomonhan Incident stands as a warning ignored about the limits of aggression driven by ideology rather than sound political and military strategy and tactics. It revealed the dangers Clausewitz warned of: wars initiated for political symbolism without a clear path to decisive victory would ultimately end in disaster for those who initiated the action.

Nomonhan was not merely a border clash. It was Japan’s strategic crossroads. Historians have come to now recognize Nomonhan as one of the most consequential “incidents” of the twentieth century – even though it largely remains unknown in the West.

Image credit: various photographs from Naval Aviation Museum, National World War II Museum, and US Navy Archives. | Pacific area map of 1939 courtesy of MapWorks via Wikipedia Commons.

After the Marco Polo Bridge Incident (July 1937)  the United States took measured but meaningful actions in support of China, while still stopping well short of alliance or military intervention. The pattern is best described as moral, diplomatic, and limited material support, shaped and heavily limited by existing U.S. neutrality laws and the general sense of isolationism among the American people and Congress.

Given the mood and legal constraints facing the Roosevelt administration there was little to be done if the goal was to avoid military actions. What actions were taken are best described as nonrecognition and positioning. To that end the U.S. refused to recognize Japanese territorial gains in China, continued to uphold and advocate the Open Door Policy regarding commercial trade with China, and treated China as the legitimate sovereign power throughout the conflict.

This stance mattered because it denied Japan international legitimacy as virtually all nations followed the U.S. lead in this matter. It also gave China an enhanced standing in international diplomatic forums. The actions, limited as they were, did signal U.S. sympathy without military commitment. While Secretary Cordell Hull worked the diplomatic world, striking a balance that applied limited international pressure in a moral sense to Japan, he also had to temper calls from Britain for concrete economic sanctions. Britain was at the threshold of war in Europe (which began September 1939) and was concerned with Japanese aggression in the Asia Pacific area against British colonies and interests.

A Divided Asian Policy

In the post “American Diplomacy in 1937” we considered some of the key figures in determining the U.S. diplomatic response to Japanese aggression in China: President Franklin D. Roosevelt; Cordell Hull, Secretary of State; Stanley Hornbeck who headed the Far East Department; Nelson Johnson, Ambassador to China; Joseph Drew, Ambassador to Japan; and key advisors to Hull – J. Pierpoint Moffat and Hugh Wilson. Moffat was the son-in-law of Joseph Drew. Wilson had served in Japan in the mid-1920s.

Roosevelt, Hornbeck and Johnson can be viewed as members of an “activist camp” although in varying degrees. Hull, Grew, Moffat and Wilson would be viewed as members of a “don’t aggravate Japan” camp who wanted to confine U.S. responses to diplomatic channels while avoiding economic sanctions of any form as well as military action. At this point “military action” primarily meant action by naval and marines forces stationed in Shanghai as protection of U.S. citizens and interest in Shanghai’s International Settlement as well as citizens and interests upstream on the Yangtze River.

Hull’s position was to do nothing to antagonize Japan but nothing to assist them either. President Roosevelt did not like Hull’s Asian policy. While he accepted them as prudent the President was frustrated by a policy that let Japan get away with blatant aggression. Roosevelt was known to keep his own counsel and on occasion “go his own way.” In October 1937 he gave what came to be known as the Quarantine Speech that implicitly condemned Japan’s aggression (alongside Italy and Germany). In the speech he framed Japan as a disturber of international order but deliberately avoided naming Japan to prevent escalation. But his meaning was clear: “The present reign of terror and international lawlessness… [means that] the very foundations of civilization are seriously threatened…international anarchy destroys every foundation of peace…This situation is of universal concern.” Roosevelt went on to compare the terror and lawlessness to a contagion becoming an epidemic and note that the only reaction to an epidemic is quarantine. “War is a contagion, whether it be declared or undeclared…There must be positive endeavors to preserve peace.”

The speech did everything that Hull was trying to avoid. First, it exacerbated diplomatic relations with Japan. Although Roosevelt never named Japan, Japanese leaders and the press immediately understood that Japan was one of the principal targets. From Tokyo’s perspective, the speech signaled that the United States was morally siding with China, Japan was being described as a threat to international order, not merely a regional power pursuing interests, U.S. neutrality was becoming conditional rather than detached, and this signaled a shift from U.S. disapproval to U.S. warning.

The Japanese Foreign Ministry responded with measured, non-confrontational statements. This restraint reflected a desire to avoid provoking sanctions, an awareness that Japan still depended heavily on U.S. trade, and a hope that American isolationism would reassert itself. In the Cabinet it was viewed as a trial balloon for later economic sanctions. Within the military it added to the view that the U.S. viewed them as a second-rate nation. The Japanese Army dismissed it as moralizing. Within the Navy the speech confirmed fears that American opinion was shifting and that the current moral pressure could evolve into economic or naval measures – but still considered armed conflict years away.

Hull was also concerned that the speech would have the western signatories to the Nine Power Treaty call for an international conference (which it did) and that the U.S. would be thrust into the leadership role. Within domestic politics/policy it marked the beginning of a division within the nation’s foreign policy with Roosevelt pushing for something more dynamic and assertive – and yet not giving any concrete substance to the notion – while at the same time Hull was trying to maintain the established policy. 

This difference would prove to be somewhat problematic as Roosevelt tended to think in broad, sweeping terms while avoiding detailed plans. Hull tended to think in categories of fundamental goals without incremental steps towards that end.

Proposals and Next Steps

Among the activists, Hornbeck shared Hull’s conviction that diplomatically Japan was not an honest dialogue partner, but also understood Japan’s foundational interests: economic and political security in her area of interest. While much of the U.S. Department of State believed Japan had “taken on more than it could chew,” Hornbeck understood that with every bite, Japan’s appetite increased, but that there were very different levels of “appetites” between the nationalist/militarists in Japan and their moderate counterparts in civil governance and diplomacy. Hornbeck wanted to actively approach Japan with the “carrot” that would give them the security they desired, but needed a “stick” to forestall further Japanese aggression in China. In this he was aligned with President Roosevelt, but the President in 1937 did not believe he had the support of either Congress or the public for any form of “carrot.”

While the U.S. internal debates continued and Japan aggressively moved in China, an element of the Japanese government initiated “feelers” from offices in Tokyo, Washington DC, and Paris. They wanted to see if the U.S. would help present Japan’s terms for peace and moderate Sino-Japanese talks. Unfortunately, Japan’s offer matched their history of vague diplomacy, asking for specific current actions from China while pinning their commitments to future events that might or might not happen. Ambassador Grew in Japan, in general more positive about Japan than others, acknowledged that his analysis of the terms to China were really full capitulation couched in ambiguous language. Grew attempted to get Japan to commit to “details” consistent with the Nine Nations Treaty of which Japan was a signatory. Eventually the initiative “died on the vine.”

By December 1937, Treasury Secretary Morgenthau, of a like mind with Roosevlet and Hull, raised the possibility of beginning to seize Japanese assets held in the U.S. as a first step. Roosevelt was initially keen on the idea, but by late January 1938 that initiative “died on the vine.”

There were other initiatives but in the end all suffered the same fate. The U.S. was not able to field a policy for Japan other than Hull’s “don’t aggravate, just wait.” Some of the division and lack of action was certainly tied to U.S. politics with the American people largely isolationists, still suffering from effects of the Great Depression, and mid-term elections being close by. But a good deal was connected to the divisions with the State Department.  Ambassador Grew, long serving in Japan, had a belief in the moderates of the party – people he had known since the 1920s. Historians agree that he placed too much emphasis on the standings of the moderates, who by the 1930s were largely sidelined.  With Washington DC, the Far East Department (FED) firmly believed that the nationalists and military elements held key control of Japan’s policies. FED believed that Japan had not only regional but global aspirations and foresaw in the spring of 1938 that Japan would formally partner with Germany and Italy – which they did in the September 1940 Tripartite Treaty.

By the Spring of 1938, China was holding its own…to some degree. Hull concluded that Japan was overextended, lacked the resources to capture China, much less control China, and concluded that Japan would never win the war. And that they might even lose the war over time. This “betwixt-and-between” view was supported by General Joseph Stillwell, US Army, an advisor to Chiang Kai-shek.  The next effect was to further convince Hull that his policy of waiting while not aggravating Japan was the right course of action.

As a result, a routine was established:  Japan took some action which required Ambassador Grew to protest. Japan offered conciliatory words with no concrete actions apart from a renewed request for the U.S. to moderate peace talks (as before). In the end, with no actions forthcoming, the U.S. would formally protest. Japan did not respond.  It was a cycle of rinse and repeat as each incident came along.

In May 1938, Japan initiated a campaign of strategic bombing of Chinese civilian populations. This campaign was extensively covered by U.S. news outlets and American missionaries. At the movies, new reels and reports of the campaign were seen by the American public. It is estimated that in 1938, in urban America, the average adult saw two movies in-theatre each week. It did not take long for a wave of public outcry to arise. From that came the calls for U.S. companies to stop their “blood trade” with Japan. The outcry forced Hull to initiate a “moral embargo” asking U.S. companies to voluntarily stop trade with Japan in aircraft, aviation maintenance items, aviation fuel, and key resources and tools needed for the production of war goods. Hull’s goal was to calm the U.S. public.  At the same time Hornbeck and other departments in State wanted the U.S. to abrogate the 1911 U.S.-Japan Trade Agreement.

The war in China continued through the summer and into the autumn. The Chinese lost the city Xuzhou at the end of May but the battle proved the Chinese strategy of attrition that increasingly made Japan pay an ever increasing costs in terms of casualties and equipment. The Japanese were drawn into the Battle of Wuhan which involved over 1 million soldiers and great loss, but marked the end of Japan’s rapid advance and the beginning of a long-term strategic stalemate. This advance was also forestalled when Chinese forces breached the dikes of Yangtze River, creating a massive, man-made flood to block the Japanese advance.

In November 1938, the Prime Minister of Japan, Prince Konoe, gave what is called the “New Order” speech that made public what the Far East Department (FED) had long promoted – Japan’s ambitions were super regional and also global. This was the start of a coming change within the State Department, the Treasury Department and Congress to make loans to China and begin to discuss abrogating the 1911 U.S.-Japan trade agreement. Withdrawing from this agreement made later sanctions and embargoes possible.

Of interest is also at this time, Ambassador Grew was vacationing in the United States, and when asked the Charge of Affairs Doorman reported that the military and nationalists were in complete control of the governance of Japan. This March 1939.

Image credit: various photographs from Naval Aviation Museum, National World War II Museum, and US Navy Archive

So far in this series we have worked our way up to 1937. From the summer of 1937 until Pearl Harbor the conflict in mainland China is the dominant factor that drives and animates Japan’s relationships (or lack thereof) with China, the United States, Britain, the Netherlands, and all the nations of the Asia-Pacific region. The ebb and flow of this conflict known as the Second Sino-Japanese War is really the beginning of the Asia Pacific War that will become World War II upon the 1939 outbreak of war on the European continent and the entry of the United States into the war after the attack on Pearly Harbor in December 1941. 

The Second Sino-Japanese War began not as a formally declared conflict but as a local military clash that escalated beyond political control, reflecting the structural weaknesses of both Chinese sovereignty and Japanese civilian authority over the Imperial Japanese Army (IJA). From the Marco Polo Bridge Incident in July 1937 to the summer of 1941, the war evolved from a short punitive campaign into a protracted, brutal struggle that reshaped East Asia and set Japan on an increasingly irreversible path toward wider war.

The Marco Polo Bridge Incident and the Slide into War

Since 1905 and the Boxer Revolt in China, foreign nations, including Japan, had the right to station troops to protect their nationals and legations. For the Japanese this included guarding key railway lines connecting Beijing to the port of Tianjin. The Marco Polo Bridge spanned the Yongding River and sat on the main rail and road routes linking Beijing and Tianjin. As such it was of high strategic importance to Japan and a tactical chokepoint. Because of this Japanese units frequently patrolled and trained nearby. Night exercises were common and technically permitted under treaty arrangements.

On July 7th, Japanese troops were conducting a night training exercise near the bridge when one soldier failed to return, Japanese officers suspected detention by Chinese forces and demanded entry into a local city to search for their comrade; the Chinese refused. Shots were exchanged, and the situation escalated.

Similar incidents had occurred before and had been defused diplomatically. What made 1937 different was not the presence of troops, but the political climate surrounding the incident.

By 1937 Chiang Kai-shek’s coalition of northern and central warlords was deemed to be weakening in the view of the Japanese. This gave the Japanese field commanders (junior officers) the opportunity to aggressively respond as was their inclination. As discussed previously, by this time the field commanders knew that the civilian leaders in Tokyo were reluctant to restrain the Kwantung Army and so they pressed ahead. But they had misread the resolve of the Chinese leaders. So to speak, this time the incident was a bridge too far. The system that once contained incidents had broken down. Neither side was willing or able to step back once violence occurred. Mutual distrust, heightened nationalism, and the absence of firm political restraint allowed the confrontation to spiral.

Neither Tokyo nor Nanjing initially sought full-scale war. Japanese civilian leaders hoped to localize the conflict, while Chiang Kai-shek remained cautious, wary of Japan’s military superiority. Yet Japanese field commanders continued to press forward, and political leaders in Tokyo, fearful of appearing weak and constrained by past precedents of insubordination, ratified military escalation rather than restraining it.

By late July, Japanese forces had seized Beijing and Tianjin. What might once have ended in diplomatic compromise instead became a test of national will.

Shanghai and the Expansion of the War

The conflict escalated dramatically with the Battle of Shanghai (August–November 1937) a key seaport and source of income to the Chinese government. The Marco Polo Bridge incident ignited the conflict; Shanghai made it irreversible. Before August 1937, both governments still claimed to want containment and find a “local solution.” But locally, the Japanese approach into the region was a punitive campaign initiated by local field commanders and Shanghai was the goal.

Shanghai was China’s economic and financial center. It was a major port for foreign trade and it controlled the Yangtze River which was the “highway” into Central China. By 1937, Japan had a large civilian population and commercial interests in Shanghai including banking and shipping. As well, Japan had naval facilities and marines stationed in their part of the International Settlement. Any fighting in or near Shanghai could be framed as protecting Japanese nationals and treaty rights giving them a legally defensible pretext for military involvement. The hope was to draw Chiang Kai-shek into battle, force him to negotiate resulting in a collapse of Chinese Nationalist morale, and bring the war to a quick end. This reflected a persistent Japanese belief that China would not endure sustained pressure. That working theory had not proved true in Manchuria which Japan still struggled to control. It would not provide true now nor would it prove true at any point over the next 8 years.

Chiang Kai-shek understood the Japanese intent and chose to commit his best German-trained divisions in China’s most international city.  His aim was to demonstrate Chinese resistance to the international community with its large contingent of foreign press and media. While the Marco Polo Bridge was “out of sight”, Shanghai would force Japan to fight in full view of the world. Video of the fighting became a staple in US movie theatres in the news trailers that preceded the feature film. Chiang hoped the result would be foreign mediation and that they might intervene diplomatically.

Japan responded with overwhelming force, deploying naval, air, and ground units. Once fighting began, Japanese prestige and military logic demanded escalation rather than withdrawal. The battle became one of the largest and bloodiest urban engagements of the interwar period. Although Japan ultimately captured Shanghai, the cost in casualties, time, and resources dashed Japanese assumptions of a quick victory. But it did not extinguish the IJA’s optimism about the glory or destiny of the war.

The Shanghai campaign marked a turning point as the war became total in scope, involving mass mobilization on both sides. At home as the Japanese press reported success while not reporting the tremendous losses, Japanese public opinion increasingly supported the war and the Army, making it even more difficult as diplomatic compromise became increasingly untenable. The intentional strategic bombing of civilian areas as a means of breaking morale exacerbated the breakdown.

Shanghai became a symbolic test of national honor. In China, the battle unified the Chinese factions in the common cause against Japan – even the Communists joined. In Japan, the narrative fed into the State Shinto program that the Army’s sacrifice demanded public support and sacrifice all the way to victory.

After months of brutal fighting any compromise would be perceived as betrayal as the war became morally and emotionally entrenched in the psyche of the nations. There were no diplomatic off-ramps. Japan rejected mediation efforts and were on the road to total victory. China could not accept terms without sovereignty remaining intact. Historians often note that before Shanghai, war was possible. After Shanghai, peace was politically unimaginable.

Nanjing and the Descent into Atrocity

Following the fall of Shanghai, Japanese forces advanced up the Yangtze River toward Nanjing, then the capital of the Nationalist government. The city fell in December 1937, after Chiang Kai-shek had withdrawn the government inland to Wuhan.

What followed, the Nanjing Massacre (also known as the Rape of Nanking) became one of the most infamous episodes of the war. Over several weeks, Japanese troops committed widespread atrocities, including mass killings, rape, and looting. Estimates of the dead range from tens of thousands to over two hundred thousand.

The significance of Nanjing extended beyond the immediate horror. It destroyed Japan’s international reputation, hardened Chinese resistance, made negotiated peace politically impossible for Chiang Kai-shek, and deepened Japan’s moral and diplomatic isolation. Within Japan, however, the massacre did not provoke accountability; rather, it was subsumed beneath censorship and nationalist narratives, reinforcing the pattern established after earlier acts of military excess.

Nanjing was the most visible atrocity of the Second Sino-Japanese War, but it was only one episode in a broader pattern of mass killing, terror, and repression that unfolded across China from 1937 to 1945. Most historians agree that atrocities were systemic, not accidental and that violence escalated as Japan failed to secure quick victory. The dehumanization of Chinese civilians became embedded in military practice and was demonstrated in the 1938 Wuhan Campaign and Yangtze Valley operations, the Sankō Sakusen  (kill all, burn all, loot all) policy in Chinese Communist areas from 1940-1943, the 1943 Changjiao Massacre, and the list goes on.

Stalemate and the Failure of Decisive Victory

By early 1938, Japan controlled China’s major cities, ports, and railways but not China itself. The Nationalist government retreated first to Wuhan, then to Chongqing, deep in China’s interior. From there, Chiang adopted a strategy of protracted resistance and giving up territory to garner time while the Japanese were stretched even thinner. At the core, Chiang relied on China’s vast geography and population.

Japan faced a growing dilemma as military success did not translate into political control. The vastness of their conquest and occupation required ever-larger troop commitments. The IJA had been modeled on the Prussian system, and yet Japan failed to understand the noted war theorist, Hans Clausewitz who argued that merely occupying territory is not the same as defeating an enemy. If an occupier controls cities, roads, and fortresses but fails to destroy the enemy’s army, government, or will to resist, the population will turn to partisan guerrilla warfare. Such resistance can and will bleed the occupier over time, even when conventional victory seems complete. The fall of Wuhan in October 1938 failed to end the war. Instead, Japan found itself trapped in what many leaders privately acknowledged as a “China quagmire”, though publicly they insisted on eventual victory.

Ideology, Policy, and the Deepening War

As the war dragged on, Japan’s political and ideological posture hardened. In January 1938, Prime Minister Konoe declared that Japan would no longer deal with Chiang Kai-shek’s government, foreclosing diplomatic settlement. This decision, often cited by historians as a critical error, was driven by military pressure, nationalist public opinion, and the belief that China would eventually collapse internally. In practice, this policy eliminated Japan’s best chance for a negotiated exit.

Japan attempted instead to construct a “New Order in East Asia”, envisioning China as a subordinate partner under Japanese leadership. In reality, this meant expanded occupation, collaborationist regimes, and intensified repression.

Throughout this period, the United States remained formally neutral, but increasingly sympathetic to China. American responses included moral condemnation of Japanese aggression, loans and limited aid to the Chinese government, and growing public outrage after incidents such as the Panay Incident (1937) when the Japanese sank a U.S. gunboat involved in rescue operations of U.S. citizens along the Yangtze River. However, until 1940, U.S. actions remained cautious, constrained by isolationism and legal neutrality. Japanese leaders interpreted this restraint as reluctance to intervene militarily, reinforcing the belief that the China war could continue without provoking direct conflict with the United States.

The Road to Wider War, 1939–1941

By 1939–1940, the war in China had become institutionalized. Japan had mobilized society for long-term conflict. Military influence over government had deepened and political dissent was suppressed. The outbreak of war in Europe in 1939 altered Japan’s strategic calculations. With France defeated and Britain embattled, Japan turned increasingly toward southern expansion, while continuing the China war without resolution.

In 1940, Japan signed the Tripartite Pact with Germany and Italy, further alarming the United States. American responses escalated gradually to include export controls on aviation fuel and scrap metal, increased support for China, and increased strategic planning for potential conflict with Japan. In July 1941, Japan’s occupation of southern Indochina prompted the United States to impose a freeze on Japanese assets and an effective oil embargo. By this point, Japan was fighting an unwinnable war in China while facing mounting pressure from the world’s leading industrial power.

From the Marco Polo Bridge Incident to the summer of 1941, the Second Sino-Japanese War evolved from a local confrontation into a protracted, brutal, and strategically disastrous conflict. Japan’s inability to control its own military escalation, combined with nationalist ideology and structural flaws in governance, transformed early victories into long-term overextension. For China, the war became one of survival, unity forged through suffering. For Japan, it became the central trap from which all subsequent decisions would follow: southern expansion to the Southwest Pacific region, confrontation with the United States, and ultimately the full Asia Pacific War.

Image credit: various photographs from Naval Aviation Museum, National World War II Museum, and US Navy Archives.

It would be a herculean task to consider all the elements and forces in the boiling pot that was the Asia Pacific region in the summer of 1937. And even then to understand the levers available to the U.S. to affect the military action in China and Manchuria that was initiated by Japan. Historians argue for or against financial leverage, military leverage, diplomatic leverage and a host of other factors. A book has been written that argues a coalition of merchant shipping companies could have been assembled that could have been effective in controlling Japan because of Japan’s dependence on foreign-flagged merchants to deliver even basic food items. Perhaps the most often discussed topic is that the United States missed a window of opportunity to broker peace between China and Japan that would have set in motion a chain of events so that the United States was never drawn into the war against Japan.

Background: US Foreign Policy

The priority of the President of the United States and the State Department was Europe and the rise of fascism in Italy and Germany, as well as the ongoing Spanish Civil War which was seen as a proxy for the coming conflict in Europe. It was also the priority for Britain and during this period they exerted diplomatic pressure to ensure the U.S. kept Europe as the priority. Nonetheless, the U.S. needed to pay attention to the Asia-Pacific region because of interests in China, the Philippines, Guam and elsewhere.

Some of the key players at the U.S. State Department were: Cordell Hull, Secretary of State; Stanley Hornbeck who headed the Far East Department; Nelson Johnson, Ambassador to China; Joseph Drew, Ambassador to Japan; and key advisors to Hull – J. Pierpoint Moffat and Hugh Wilson. Moffat was the son-in-law of Joseph Drew. Wilson had served in Japan in the mid-1920s.

Hull shared a view with Hornbeck: Japan was not trustworthy given their history of vague diplomacy, military aggression apart from civilian control, and a habit to ask specific current action of the U.S. while pinning their commitments to future events that might or might not happen. By the 1930s they were not considered to be forthright in their diplomacy. In the 1920s, when there was a strong current of liberal democracy, Japanese diplomats were effective – perhaps because the western nations (i.e., U.S. and Britain) achieved their goals. Meanwhile, at home, the military/nationalist parties considered the diplomats to have harmed Japan in strategy and in honor. By the 1930s, it was this latter group that dominated internal and external politics and policy, even as Japan’s diplomatic core retained career people from the 1920s. 

It must be noted that even at this point in history (1937), the U.S. had already broken the Japanese diplomatic cables and traffic (not the military). The U.S. was often reading diplomatic correspondence before the intended Japanese recipient. The distrust was rooted, not only in experience with Japan’s diplomacy of the 1930s, but also with evidence of current intentions revealed in the diplomatic cables.

Perceptions within the State Department

While Hull and Hornbeck agreed it was appropriate to be very cautious in dealing with Japan, where they were not on the same page as regards to “the next steps.” Hull was very much a diplomat who was pragmatic but at the same time was more interested in a lasting settlement rather than incremental steps to such a settlement. His emphasis was always on fundamental principles.  Hull’s experience with Japan was they negotiated to keep options open, were reluctant to commit to hard action, dates and consequences, and most often replied with vague ideas or contingent events whose outcome was rarely knowable.  In addition, the principled but pragmatic Hull believed that the U.S. did not have adequate naval assets to project power to the western Pacific; did not have substantive national interests in China to warrant the threat of military action; understood that any action taken in the summer of 1937 had zero popular support; and that the U.S. did not possess sufficient financial leverage to entice/force Japan to modify its China program. Hull did note in correspondence that “Japan’s invasion of China was not desirable but not intolerable.” 

Hornbeck and Johnson believed that Japan’s aggression would never be limited to China but would eventually expand to include the Southwest Pacific, especially the oil rich nations. Japan wanted diplomatic and trade action that would legitimize their expansive actions, both categories of which were turned down by Hull and President Roosevelt. Hull’s position was to do nothing to antagonize Japan but nothing to assist them either. Roosevelt’s position was harder to pin down. He would agree that the U.S. should do nothing to aggravate Japan, then he would make a very public speech, e.g. Chicago 1937, when we would openly criticize Japan’s aggression and seem to call for a “moral embargo” from U.S. citizens and companies to not buy Japanese goods. In any case, there was nothing concrete that was offered to mitigate Japan’s actions – and that was, in part, due to pressure from Britain and the Netherlands who had substantive interests and holding in the Southwest Pacific – the very target of Japan’s attention.  

The Neutrality Acts

The U.S. was also constrained by the Neutrality Acts. By 1937 the acts prohibited arms sales to all belligerents – in this case China and Japan. It was designed to keep the U.S. isolated. This initially gave Japan a freer hand in its aggression against China without fear of U.S. intervention. Following the outbreak of the Second Sino-Japanese War in 1937, President Roosevelt did not invoke the Neutrality Acts, arguing that no formal declaration of war had been made. This allowed the U.S. to avoid hindering China’s defense, allowing for the shipment of arms to China, which frustrated Japan.

The 1937 Act introduced cash-and-carry, allowing the sale of non-lethal, and later other goods, if paid for upfront and transported by the buyer. While this technically allowed Japan to purchase supplies, Roosevelt selectively used this to enforce a moral embargo on aircraft sales to Japan. Revisionist historians (and what this often means is just the 2nd wave of historians) see this as escalating tensions, making diplomatic resolution difficult. Or as some argue, impossible, as it forced Japan to choose between abandoning its expansionist goals or initiating war to secure needed resources. 

This latter line of reasoning continues as time moves into 1941 concluding that every action of the U.S. to limit Japan’s ability to buy scrap steel, key material resources, aviation fuel, freezing of U.S. held Japanese financial resources, and eventually a complete oil embargo – all “caused” Japan to start the war. In the several books with trajectories along this line (Utley’s Going to War with Japan 1937-1941 and Miller’s Bankrupting the Enemy) while interesting insights and historical details are offered, the analysis seems to miss that Japan had options. In 1937, military spending was 45% of Japan’s national budget and would grow to 65% by 1940; in the United States military spending was 3% (1937). There was more than enough budget for Japan to focus on becoming a commercial powerhouse (as it became post WW2). The currents of history led Japan to become a nation with an outlook on the world similar to Nazi Germany. There is also little to no mention of the rapidly growing death toll in China among civilians and the devastation of cities and economies.

Bankrupting the Enemy acknowledges that the Japanese leadership justified the war as self-defense against the United States, who was trying to strangulate and pauperize Japan and that this was the prevailing view among the majority of government/military leaders in Japan at that time who controlled the nation. Going to War with Japan 1937-1941 notes that Grew, Moffat and Wilson were in contact with the Japanese government who wanted the U.S. to approach Japan offering to moderate a peace settlement with China. True, but in reality they were only in dialogue with the moderate wing of Japanese politics who held no influence within the cabinet, the Diet, the military, and little if any with the Imperial household. The revisionist view seems to base their conclusions of causality on “if only we’d given the moderates a chance…” It is simply near impossible to hold that view if one understood the body politic of Japan from 1937-1941. 

The Contingent Window

A missed opportunity? Was there a window to bring peace to the Asia-Pacific region and avoid the carnage and destruction that happened from 1937 to 1945? Most historians agree that by late 1937 the political, military, and ideological conditions in Japan made a negotiated peace exceedingly unlikely, extraordinarily difficult, though not theoretically impossible even then it was only for the briefest window of time. 

There was indeed a moderate faction in the autumn of 1937 but it was fragile and divided. They included people associated with Prime Minister Konoe, a member of Japanese royalty, and considered by those connections to have access to the Prime Minister. As well there were diplomats in the Foreign Ministry, some officers in the Naval Staff worried about overextension and potential engagement with the U.S., and some Army Staff officers whose primary responsibility was logistics. All in all it was not a prestigious or influential group. It should also be noted that Konoe, as Prime Minister, was an animator for even more aggressive actions in China. As a group they were not cohesive in their aims, lacked control over field commanders, and would not act openly against the tide of nationalism.

Even at its strongest, the moderate camp faced structural barriers – first among them was the autonomy of the Army.  Field commanders often acted independently and civilian leaders could not guarantee compliance. At the same time, the war already enjoyed genuine public support, especially after early successes. Arguments again the war risked accusations of betrayal in a milieu when assassinations were not unusual. And lastly, and most importantly, the war already had Imperial legitimacy. Once the Emperor sanctioned operations, reversal became politically perilous for all involved.

Even if Japan’s moderates could convince a larger element of their own government to be receptive, the U.S. lacked any real means of leverage without economic sanctions or military force, both of which were never policy options for the U.S. Two other factors the moderates did not consider were: there was no U.S. domestic support for assertive involvement and it was likely that even an offer of American mediation risked being dismissed as hostile interference.

Was there a window of opportunity for a negotiated settlement in 1937? Theoretically, yes. Realistically, no and what is really meant is “Sure, occasionally “Hail Mary” passes work in football…but…”

By early 1938, the opportunity, if it ever existed, had effectively vanished.

The “lost moment” assertion is not absolutely wrong, but it vastly overstates the cohesion and power of Japanese moderates and underestimates the force of nationalism, military autonomy, and momentum. 

Image credit: various photographs from Naval Aviation Museum, National World War II Museum, and US Navy Archives. | 

We have slowly been working our way through the early 20th century in Japan in search of key currents and views that were shaping Japan leading up to the 1937 start of the Asia-Pacific War. The 1860s movement from the Shogunate era to the Meiji Restoration was not a move to a constitutional republic that we know and accept in the United States. It is a complex topic best described by dedicated historians. To be clear, historians do not fully agree on the role Hirohito was playing  and would play in the path to the Asia Pacific War. Nonetheless, some coverage is needed to understand how events have and will play out in 1930s Japan.

The Role of the Emperor

It is fair to say that a central goal of the Meiji Restoration was to reestablish the Emperor as a center of leadership, especially moral and symbolic leadership – but it needs to be said with qualifications.

One of the Restoration’s core aims was to overturn Tokugawa Shogunate rule, which governed in the Emperor’s name but marginalized him in practice. It was a critical aspect of the Restoration to reassert the Emperor as the legitimate source of authority for the state. This was essential for national unity during rapid modernization and would serve to legitimize institution and structural changes that would be needed for Japan to take its place in the world order. These changes included military conscription, taxation, education, state and foreign policy, and more. In this sense, the Emperor was intended as the moral and symbolic center of the new order.

But that was not to say the architects of the Restoration intended the Emperor to be involved in day-to-day operation of the State. Many of the Restoration leaders were themselves daimyō (regional rulers) in the Shogunate  era. While they did not want a Shogun, neither did they intend the Emperor to govern directly. Influenced by Chinese and Western polity, they designed the ruling structures so that real power rested with the cabinet, bureaucracy, and the genrō – the elder statesmen of the era as it happens, themselves). The result was that the Emperor’s role was to sanction and embody decisions, not originate policy. This aligns with the idea of moral leadership rather than active governance.

Yet he served an important political function. The Emperor’s restored status provided continuity with Japan’s past, neutralized factionalism by placing authority above politics, and helped suppress dissent by framing opposition as disloyalty. The emperor-centered ideology was a means to an end, not an end in itself.

By elevating the Emperor as sacred, inviolable and the source of sovereignty, the Meiji system created structural ambiguity. Policies could be justified as “the Emperor’s will” while at the same time the Emperor was shielded from responsibility. While this is a broad statement, 1931 saw military leaders act in the Emperor’s name without his consent, control or authority. He is the Commander-in-Chief of the armed forces, yet his Kwantung Army in Manchuria felt free to do what it wanted, not expecting and not receiving punishment for their actions. Emperor Hirohito’s response to the events of 1931 was to “fire” the Prime Minister and form a new government, but did not take any action within Army ranks. Most historians believe it was a choice for national stability; control could come at a later time.

That did not seem to be the response of an absolute monarch yet neither was it a role of a powerless figurehead of State. 

Prior to ascending the throne in 1926, Hirohito had taken a trip that included extended time in Britain. Among his interests was to understand the nuance and complexity of the King of England within the Constitutional Monarchy – which at the time seemed to be the closest configuration of what the Meiji founders had in mind. The historian Herbert Bix offers that King George of England shared with then Crown Prince Hirohito that the role of the monarch was also to influence the levers of power and on rare occasions to press with force. Hirohito never revealed his understanding of the role of emperor, not even after the end of the war in 1945 or later. It has left historians to research and draw their own conclusions. Historian Stephen Large offers an idea of “self-induced neutrality” – knowing he has the power but choosing not to act. Peter Wetzler believes that the Emperor knew how to put his thumb on the scale but at the same time did not believe himself to be responsible for the result. In the end his was only to approve policy, not to create it.

Whatever his actual views, his posture as Emperor from 1926 until 1937 fit into the Meiji system’s likely intent. By elevating the Emperor as divine, inviolable and the source of the nation’s sovereignty, the Meiji system created structural ambiguity wherein policies could be justified as “the Emperor’s will” and yet the Emperor was shielded from responsibility.

Sacred Duty

The education and formation ministries amplified this view of the Emperor with The Development of Sacred Duty. This was an essential idea that Japan needed to take its place among the powerful nations of the world, not only as an economic necessity but as a moral imperative rooted in its self-understanding through the eyes of Shinto religion. The argument was that if the emperor’s will was divine, then Japan’s policies (whether modernization, annexation, or war) could be framed as the fulfillment of a sacred mission. For example, in annexing Korea, Japanese officials and ideologues claimed they were “bringing civilization and order” under the emperor’s benevolent guidance.

This Shinto-based ideology taught that Japan was the land of the gods (shinkoku), uniquely pure and chosen. This translated into foreign policy as a belief that Japan had a moral right and duty to lead other Asian peoples (Korea, Taiwan, eventually China) — even if this meant dominating them. Unlike Western colonial powers, which often justified empire through Christianity or “civilizing missions,” Japan used State Shinto and emperor-centered nationalism to claim it was liberating Asia from Chinese decay or Western imperialism.

This view underpinned Japan’s expansion which was more than military force projection, it included economic and trade justifications – all connected to Japan’s need for markets, raw materials, labor, and trade routes. State Shinto teachings linked these economic aims to national survival and divine destiny. Securing resources in Korea, Taiwan, and later Manchuria wasn’t framed as “colonization,” but as fulfilling the emperor’s sacred mandate to protect and enrich his people. Thus, trade dominance and annexation were sacralized as part of a divine mission, not just pragmatic policy.

The cornerstone that held the structure together was the Emperor – or at least the idea of the Emperor.

This ideology formed the idea of The Eight Corners of the World in which the Emperor of Japan extended divine order first across East Asia then across the globe. In Korea, Manchuria and later in other conquered lands, Shinto shrines were built to enforce the symbolic inclusion of that country under Japan’s sacred imperial rule. This is the underlying foundation behind the Greater East Asia Co-Prosperity Sphere in which Asian countries should come together under Japan’s leadership to be free from Western colonial powers. On paper, it sounded like a partnership — “Asians helping Asians.” Japan said it would bring prosperity, unity, and independence to Asia. In reality, though, it mostly meant that Japan would dominate the region, control its economies, and use its resources for Japan’s benefit. So instead of being true cooperation, it was more akin to Japan empire building with kinder and gentler language and imagery. 

In the Center

At the center of the puzzle is Showa Emperor Hirohito, the 124th descendant of the Sun Goddess, son of Emperor Taisho, the son raised from birth to take his father’s place on the throne. The one who inherited the root problem passed on by his father Emperor Taisho who had positioned the throne, for all practical purposes, as a Constitutional Monarch with no real powers – or at least Taisho did not exercise any power. Internal to Japan there were supporters of this dynamic as they desired for full democratic reforms. There were detractors that saw such reforming movements as an “infection” of western ideas. When Hirohito ascended the throne, he entered into an evolving system where the Cabinet and Diet establish policy and precedence internally and externally. Was this the intent of Meiji reforms? Was it an aberration? What was to be his role? Decision maker, Imperial “whisperer” whose position was only hinted at by the question asked, or, like his father, a symbol and endorser of already made decisions. 

Historians generally describe Emperor Hirohito’s role between the Mukden Incident (1931) and the February 26 Incident (1936) as that of an engaged but constrained constitutional monarch whose authority was real yet structurally and politically limited and whose own choices increasingly favored management over confrontation. After this period, Hirohito became more engaged – how much more? But we know from this point forward Hirohito was not a passive figurehead. He received regular briefings from Army and Navy Chiefs of Staff, questioned military plans and timelines, and expressed concern about unauthorized actions, especially after Mukden. But Hirohito accepted the military’s assurances and fait accomplis rather than force a constitutional crisis. He was aware of this history of assassinations and divisions within the Army and strategically chose to avoid civil war or regicide. It was the latter in 1936 when Hirohito personally ordered the suppression of the coup. When the throne itself was directly threatened, he acted decisively. Hirohito could intervene, but usually chose not to unless imperial authority itself, not policy, was at stake.

1937 and Beyond

Perhaps getting ahead of ourselves, but continuing the thread, we continue to trace how Emperor Hirohito’s posture changed after 1937 when Japan’s actions initiated the Asia Pacific War with the outbreak of full-scale war against China that began with the Marco Polo Bridge Incident (July 1937)

Hirohito seems to accept the war as a reality to be managed. As Emperor he approved mobilization orders and war directives, accepting that conflict was now unavoidable. He shifted from questioning whether Japan should fight to how the war should be conducted as he focused on military feasibility, logistics, and timelines rather than political alternatives. Historians largely agree that Hirohito no longer saw the war as something he could stop without risking systemic collapse. Perhaps the one sentence description of how he viewed his role as Emperor would be: reluctant acceptance combined with managerial oversight.

As the war in China dragged on, Hirohito demanded more frequent briefings. During these briefings he often questioned generals on operational matters, including troop deployments and supply constraints. He continually expressed concern about two items. The first was overextension of the army. The IJA enjoyed continued success against Chinese forces, but that also meant longer logistic lines and a larger territory “behind the lines” for which they were now responsible.  Second, there was no clear exit strategy or end-game that could be delineated. The Emperor made his presence increasingly known, but avoided direct confrontation.

And the war dragged on. Meanwhile on the home front, the Prime Minister who was a prime animating force for Japan’s continued aggression in China, Prince Konoe formed the Imperial Rule Assistance Association (IRAA). It was an attempt to unify Japan under a totalitarian, ultranationalist banner for total war, effectively dissolving all other political parties to eliminate factionalism and mobilize the nation for its expansionist goals in China, Mongolia and Siberia. While intended to consolidate power, it struggled with internal divisions and never fully achieved the monolithic control seen in Nazi Germany, facing resistance from established interests and failing to fully control the military.

In this period Hirohito voiced unease about war with the United States because of Japan’s industrial and naval limitations. At the same time he supported diplomatic efforts but seemed to keep them “on a short leash” so that they did not undermine imperial prestige. It was also in this period that he ultimately approved The Tripartite Pact with Italy and Germany. As well he approved the expansion to the southwest, occupying French Indochina. The Emperor seemed suspended between diplomacy and military momentum, wanting the former but unwilling to tamper down the latter.

In late 1941, despite misgivings, Hirohito approved the decision for detailed war planning against the United States and Britain and sanctioned pre-war operations while insisting that diplomacy continue until the last moment. But more on that in later posts.

After the Allies entered the Asia Pacific War and the tide soon turned, Hirohito asked increasingly pointed questions, privately expressed pessimism, but avoided direct intervention that might undermine military morale. He was informed, offered suggestions, but remained largely reactive but understood his was the final consent/approval of major actions and campaigns.

It was only in August 1945, when Japan was defeated but had not yet surrendered that Hirohito overrode military opposition to accept the Potsdam Declaration, intervened directly to solve a deadlocked cabinet, and ordered the end of the war. This moment starkly contrasted with his earlier restraint but he acted to preserve the nation and the Imperial House.

Historians often describe Hirohito’s post-1937 trajectory as moving from constitutional restraint to  managerial involvement to reluctant authorization to a final decisive intervention. The paradox, the evolution if you will, is central to his legacy.

Earlier he possessed the authority to intervene but did not, seemingly out of fear of fracture, precedent, and the sacred status of the throne. He acted decisively only when national annihilation loomed

Image credit: various photographs from Naval Aviation Museum, National World War II Museum, and US Navy Archives

In the 2026 posts I have been working to go into more depth on the events prior 1941 that drew the U.S. to become involved in the Asia-Pacific War. In the first post of the new series I wrote that I wanted to explore:

“…the currents and eddies of history that brought Japan its wars with China (1894-1895 and 1937-1945), with Russia (1904-1905), the annexation of Korea, Manchuria and French Indochina, and to wider war in the Pacific that stretched from Hawaii to Australia and nations in between, notably the Philippines, Malay, Borneo and the Dutch East Indies.”

And more, I wanted to delve into the milieu of conditions that led Japan to think that the wars were necessary, why it felt the U.S. needed to be drawn into the war, understand revisionist historians who assigned large elements of blame on the U.S. for forcing Japan’s hand making war inevitable, and so many other questions – especially what made Japan think they had any possibility for winning a war that would involve the United States.

To that end I have posted a bare bones history of Japan, her people, the ages and epochs she experienced, changes in people, in forms of governance, her relationship with other Asian countries, and especially the changes in Japanese society from the end of the Shogunate period of her history into the modern times of the Meiji Restoration. After covering multiple centuries in a single post, the focus began to narrow to cover decades, and sometimes events of just a single year.

What is common to so many of the posts was something I began to explain in the post “There’s Something About China.” That post tried to address the swirl of history surrounding China, European nations, and Japan in the days of the 19th and early 20th centuries. For business people, pirates, adventurers, explorers, seekers of the mysterious and exotic – all roads lead to China. The 1930s are no different.

But the 1930s are a confluence of many emerging influences within the Japanese world, changing the lenses by which she viewed the outside world. Although Japan had been an open country after Admiral Perry’s appearance in Tokyo Bay in the 1850s, had established a robust international trade, was an allied partner in World War I, and more – she was still a closed country in many other ways. Many of those trends were discussed in the web of previous posts and are just highlighted here:

• Social Darwinism had found its way into national strategy. Control of Korea and Manchuria were seen as strategic buffers and reserves of critical resources. This allowed Japanese leaders to claim: “We do not seek conquest; we seek existence.” It is a logic that removed ethical restraint.
• The traditional Samurai spirit had been morphed into bushidō as Japan’s equivalent to Western chivalry, and proof Japan possessed a moral civilization worthy of great-power status. This was installed in the military and imperial strategy of the 20th century – as well as popular culture.
• The Imperial Army (IJA) and Navy (IJN) received heavy investments in equipment and personnel in order to become a military of a leading world power. The goal for the IJA was control of China and Russia. The measure for the IJN was the U.S. Navy as seen in Japan’s war plan, Kantai Kessen (“Decisive Battle Doctrine”). For details see the post War Plan Orange.
• While the Meiji Constitution made provisions for a Constitutional Monarchy similar to Great Britain’s, the 1920s brought new challenges to that understanding. Liberal democracy was discredited by the post-WW1 financial crises and the Wall Street crash. Rising nationalism led to a decade of Governance by Assassination which led to a military operating with impunity, free of civilian controls and juridical consequences.

Whatever national restraints that were present in the 1920s had given way to the trends above. The 1930s were marked with a rejection of the Western nations that Japan felt had already rejected her in the Washington Conferences, the League of Nations charter, and host of other post-WW1 matters. At the same time there was an embrace of a selective account of Japanese history, culture and values. The Pan-Asian aspirations had been subsumed by Japanese nationalism so that Pan-Asian aspirations and Japanese conquest were the vision and destiny. All of this is wrapped into the promotion of racial superiority in spirit and morals, a homeland that had never been successfully invaded, all under the leadership of the divine Showa Emperor, Hirohito. Destiny called. The first call was China.

The Manchurian Campaign – Mukden

“On the roads that led Japan to and beyond Pearl Harbor, the Manchurian campaign was the first signpost. Milestones had been passed, but it was in Manchuria where the road, for the first time, divided.” (Tohmatsu and Willmott, 25). 

Until 1928 or so, China was a patchwork of local war lords and shifting alliances. It made Japan’s governance of Korea, Manchuria and the Liaodong Peninsula relatively simple. But in 1928 and 1929 the Nationalist Chinese Party (Kuomintang under the leadership of Chiang Kai-shek) began to assert control over central and northern China including large swaths of Manchuria. The Manchurian warlord Zhang Zuolin has been assassinated by elements of the Japanese Kwantung Army (Kwantung is the Japanese name for Liaodong) only to see his son Chang assume power and align with the Kuomintang. Japan had formally adopted a non-interference policy for China. In the eyes of the military it was time to ignore that policy.

In 1930 nationalist operatives shot Prime Minister Hamaguchi, who survived, but the vacuum of power allowed space for the military to plan and put in place their conspiracy to expand its presence in Manchuria. The conspiracy was rooted in the Kwantung Army as well as the Army Ministry and General Staff in Tokyo. They believed a pre-emptive strike would allow Japan to take advantage of Chinese weaknesses and division. The origin of the plan was among middle-ranking officers in the Kwantung Army who believed that their actions could not be repudiated by Tokyo given the popularity of the military at home. They firmly believed that if they took the unauthorized initiative they would be able to dictate national policy. They were firm in their convictions that neither senior Kwantung officers nor the Army Ministry and General Staff in Tokyo would be able to repudiate their insubordination even insubordination that brought war. The 1928 assassination of Zhang had been the test case.

By early September 1931 the conspiracy was evident. Chiang Kai-Shek had information of what was afoot but knew he was powerless to stop it militarily and a series of river floods within China complicated his never ending power struggles with warlords and the traditional government in Nanking. He instructed the Manchuria Chang to not resist. 

The conspiracy was also known to the Emperor and Prime Minister Wakatsuki. An officer from the General Staff, Major General Tatekawa, was sent to Manchuria specifically to ensure restraint, but he found himself distracted and attentive to other matters. 

On September 18, 1931, officers of the Kwantung Army staged a small explosion on the South Manchurian Railway near Mukden and blamed it on Chinese forces. Although the damage to the railway was minimal and no Japanese trains were seriously affected, the Kwantung Army treated the incident as justification for full-scale operations. Within two hours virtually every Japanese unit in Manchuria undertook pre-planned offensive action leading to a rapid, unauthorized military takeover of Manchuria. Tokyo’s civilian government ultimately accepted the fait accompli. The Mukden Incident led to the creation of the Japanese puppet state of Manchukuo (1932), Japan’s withdrawal from the League of Nations (1933), and marked another decisive step toward unchecked military expansion and the erosion of civilian control in Japan.

There are a host of events between Mukden and 1934 that are important but can largely be described as unsuccessful attempts by the Kuomintang and affiliated groups in other parts of Northern China and Inner Mongolia to thwart the expanding control of Japan over all of Manchuria. In April 1934 Japan issued the Amau Declaration that asserted Japan had a special responsibility and leadership role in East Asia, particularly in China, and warned that Japan would oppose any foreign actions that interfered with its efforts to maintain order and stability in the region. While it stopped short of announcing formal annexations, it made clear that Japan would not tolerate outside powers, especially Western nations, challenging its political, economic, or military influence in China.

The Amau Declaration formalized Japan’s claim to regional dominance in East Asia and marked another step away from international cooperation toward coercive imperial policy in the 1930s It effectively proclaimed a Japanese sphere of influence in East Asia and was seen as an Asian version of the Monroe Doctrine, but backed by military force rather than diplomacy. The declaration further isolated Japan diplomatically and reinforced perceptions that Japan was abandoning collective security in favor of unilateral expansion.

The campaign in Manchuria proved to be the first of three Japanese offensives north of and astride the Great Wall: within Manchuria itself, in Inner Mongolia, and then in northern China. These efforts, following one after the other, lasted until early 1937, by which time Japan had secured Manchuria and, by a combination of military and other means, had largely neutralized Chinese and Kuomintang influence in Inner Mongolia and northern China.

The Response of Nations

All that was left for China was the posture of no resistance, no recognition of Japanese gains, and no negotiations with Japan. The League of Nations issued the Lytton Commission report condemning Japan. It was ignored and the report’s failure to initiate international sanctions or action proved to be the death knell of the League of Nations. Since the United States was not a League member and was Japan’s largest western trading partner, Japan saw no need to take any action.

In the United States, Franklin D. Roosevelt became president in January 1933 and started to govern amidst a powerful isolationist sentiment among the people and in Congress. We had been drawn into the European morass of World War I and would not be fooled again.

Meanwhile… the Navy

In December 1934, Japan announced it would not renew its participation in the Washington Conference treaties, especially the limits on naval combatants and auxiliary ships. In fact, Japan was already “cheating” on the accords. The Navy began to mimic the Army’s attitude as it longed for the freedom of action that the Army had simply taken for its own. The difference is that the Navy is a capital intensive investment with long lead times. At issue was the need to be unrestrained from a naval inferiority to British and American fleets as a step into support of the vision of Japan’s Asian “Monroe Doctrine” to be implemented by force of arms.

More than a decade before Admiral Kato, chief negotiator at the 1922 Washington Naval Conference, had pointedly noted that the only eventuality that could be worse for Japan than an unrestricted naval race with the United States would be war against that country. The Washington Conference had not been perfect and had required unwanted compromises from Japan, but whatever its faults, it had limited naval construction, and provided Japan with a level of naval security in the western Pacific that had never been its own to command. “This advantage was to be thrown away, and the American and British navies were to be challenged to a naval race by a service that was convinced of Japan’s special place in history. Moreover, it was equally convinced that it had in place an organization and doctrine that, given assured moral superiority over the Americans, would ensure Japan against defeat in a naval war in the Pacific. It was somewhat ironic, under these circumstances, that once limitation arrangements lapsed, both Britain and the United States laid down battleships before Japan, and it was doubly ironic that after the end of limitation, the United States laid down as many capital ships as the rest of the world put together.” (Tohmatsu and Willmott, 40)

The Aftermath

From 1934 through 1944 Japan invested in Manchuria to the extent it promoted export of critical natural resources and food.  Perhaps the key investment was in the railroads. In 1931 Manchuria had 3, 600 miles of railbed. Japan added another 2,650 miles. This extended the reach of the rail system to areas of coal mining, iron ore prospecting as well as areas with valuable reserves of magnesite, molybdenum, tungsten, and vanadium. In general, production doubled between 1931 and 1936 – most of which was exported to Japan. Geological exploration saw estimates of iron ore reserves increase from 400 million tons to 2,700 million tons. All of these resources were critical to the military and the supporting industrial complex.

Ten years of Japanese rule witnessed the construction of 2,650 miles of railway to add to the 3,600 miles that had existed in 1931. Coal production in Manchuria rose from 8,950,000 tons in 1931 to 13,800,000 tons in 1936, and iron output rose from 673,000 tons to 1,325,000 tons in the same period. Japanese surveys and prospecting resulted in the revision of estimated reserves of iron ore from 400 million tons to 2,700 million tons and of coal from 4,800 million tons to 20,000 million tons as well as in the discovery of valuable reserves of magnesite, molybdenum, tungsten, and vanadium (critical to steel alloy production). 

U.S. Reaction

From 1931 to the outbreak of the Second Sino-Japanese War in 1937 the U.S. reaction was largely restrained and limited to what might be best described as moral opposition. The Stimson Doctrine refused to recognize Manchukuo, the Japanese puppet state in Manchuria as well as other territorial changes achieved by force. It placed U.S. opposition on record, but was otherwise meaningless to Japan.

In 1943 Congress passed The Tydings–McDuffie Act that granted a path to Philippine independence by 1946. Japan concluded that the U.S. was starting a long-term reduction in their military presence in what Japan considered its sphere of influence. It was also seen as a sign that America’s isolationist movement was also evidence of a lack of U.S. willingness and resolve to resist further Japanese expansion in the Asia-Pacific region.

In the period 1935-1937, Congress passed a series of Neutrality Acts aimed at avoiding entanglement in foreign wars. These laws restricted arms sales to belligerents and, it seemed to Japan, more indication of the strong isolationist sentiment in the U.S.  This reinforced Japanese assumptions that the U.S. would avoid direct involvement in an Asian conflict and limited Roosevelt’s freedom to act forcefully even if he had wanted to.

Within the diplomatic and intelligence circles, observers increasingly warned that Japan was moving toward full-scale war in China and that moderate civilian control in Tokyo was collapsing. The U.S. quietly increased naval planning and contingency studies, though without public confrontation with Japan.

Up to this point in time there were no embargoes, no assets were frozen, and no trade restrictions specifically targeting Japan. This restraint contrasts sharply with post-1937 policy, when sanctions gradually escalated.

All in all, U.S. actions signaled disapproval but not deterrence. This left a gap that Japanese leaders and officers increasingly understood.

Image credit: various photographs from Naval Aviation Museum, National World War II Museum, and US Navy Archives
Source credit: A Gathering Darkness: The Coming of War to the Far East and the Pacific, 1921–1942 by Haruo Tohmatsu and H.P. Willmott