1. Introduction

In the early 1930s, the shadow of war shrouded the Eastern Hemisphere. Since 1931, Japan had been invading China, and gradually began to threaten the overseas interests of the United States, whether in China, the Philippines, or even Australia. Whether it was protecting the security of democratic systems from an ideological perspective or safeguarding American national interests, the United States should respond to Japan’s actions. However, the world’s largest democratic country that time implemented a policy of appeasement towards militant imperial Japan, until the end of 1930s and the outbreak of war in 1941. This policy covers both political and economic aspects, including not imposing sanctions on Japan and continuing to exporting war materials to Japan. This actually condoned Japan’s aggressive behavior and fueled the aggressive ambitions of this militaristic country. It cannot be denied that there were extremely close economic ties between the United States and Japan before the war, but the non-intervention attitude of the United States towards Japan's aggression during the Sino Japanese War was still remarkably prominent throughout the world.

So the question is: What was the purpose of implementing the appeasement policy in the United States?

For the policy of appeasement, people often discuss the conspiracy of Munich in 1938, while ignoring the appeasement of Japan by the United States before the Pacific War. Considering that the United States joined the Second World War precisely because of Japan’s surprise attack on Pearl Harbor, studying the role of appeasement policy in the origin of the Second World War cannot simply focus on the European appeasement. For the people of countries such as China that have suffered from fascist aggression the appeasement policy which sacrifices the interests of small countries for sake of national security, has been widely criticized by scholars. The traditional theory holds that appeasement policy is extremely irresponsible, especially for a major country like the United States that has international obligations. However, new perspectives suggest that appeasement policies can also be a viable means at certain times, although they may be unethical. Therefore, the answer to this question will undoubtedly have a certain impact on people’s views on the policy of appeasement.

This paper argues that the United States’ president Franklin Roosevelt, as a liberal internationalist, had no reason to ignore Japan’s expansionist actions. On the contrary, his implementation of this appeasement policy was aimed at overcoming domestic isolationist tendencies, in order to intervene the war. Specifically, Roosevelt wanted to be prepared to launch a war against Japan, but the isolationist ideology at home limited the Roosevelt administration’s war preparations. In order to reverse the isolationist trend and provide a better domestic political environment for the United States’ war preparations, the Roosevelt administration implemented a policy of appeasement towards Japan, stimulating Japan’s aggressive ambitions and thereby reversing the domestic isolationist trend, making public opinion support the United States’ war preparations. More generally, this example shows that the policy of appeasement is one of the means by which national leaders influence domestic politics by changing the international situation.

In the remainder of this paper, current arguments will be discussed initially. A systematic description of a new theory will then be provided and compared with existing theories. Following this, empirical verification of the new theory will be conducted. The paper concludes by reiterating the argument and providing implications.

2. Literature review

As a hot topic exploring the origins of the Second World War, the appeasement policy of the United States towards Japan before the Pacific War has been discussed by many scholars. Generally speaking, scholars’ evaluations of this policy in the past can be divided into two factions: one faction believes that the US appeasement policy towards Japan before the Pacific War was to prepare for a possible US-Japan war in the future. The other faction holds a completely opposite view, believing that the implementation of this policy was to avoid war with Japan. This section will briefly analyze and explain the viewpoints proposed by these two factions of scholars, and point out the shortcomings of these related research.

2.1. Prepare for war

Some scholars believe that the appeasement policy implemented by the United States towards Japan in the 1930s was based on the clear judgement that war would inevitably break out between the United States and Japan. Under this premise, the policy of appeasement was the result of comprehensive consideration of domestic and international situations, with the aim of obtaining better conditions for the United States to join the war.

Norrin M.Ripsman and Jack S.Levy argued that the purpose of the Great Britain’s appeasement policy towards the Nazi Germany was to buy time for joining the war, in order to reorganize the military. They analyzed the military situation of Britain before and after the Munich Conference and the proposals of British political decision-makers, and found that Britain’s military had significantly strengthened during this period. It can be concluded that the purpose of Britain’s appeasement of the Nazi Germany was to appease Germany in order to buy time for rearmament. One of the implications of their conclusion is that the purpose of the United States’ appeasement policy towards Japan in the 1930s was also to buy time for rearmament. At the same time, they also reclassified the theory of appeasement policy, dividing it into three categories: one to resolve grievances, one to diffuse secondary threats, and the last one to buy time.[1]

Their theory does provide a new perspective for people to understand the appeasement policies of Britain and the United States towards Germany and Japan, as well as the origins of the Second World War. However, their understanding of appeasement policies still has certain limitations. They discussed more about the more defensive side of the appeasement policy, but rarely talked about the passive side. It also ignored the different impacts of appeasement policies on domestic politics. This does not fully comply with all appeasement situations.

2.2. Avoid war

Some other scholars argued that the purpose of the United States’ policy towards Japan in the 1930s was to avoid the war with Japan. Tang Qing analyzed the evaluation of the US policy towards Japan before the Pacific War and concluded that the core of the United States’ policy towards Japan from 1931 to 1941 was to avoid assuming obligations and getting involved in the war.[2]

Scott D.Sagan believes that the US policy towards Japan before the Pacific War was a purely deterrent policy. He examined the changes in pre-Pacific War US Japan relations from this perspective and believed that the unintentional provocation by the United States in crisis management and underestimation of Japan’s willingness to wage war were significant factors in the failure of deterrence and triggered the Pacific War.[3]

Daniel Treisman mainly explored whether appeasement policy (a policy of avoiding conflicts through unilateral concessions) is always disastrous in international relations. He demonstrated through a series of models that appeasement may be a rational choice in situations where resources are limited and multiple challenges are faced.[4] From this conclusion, it can be inferred that the United States had limited resources to face threats from Germany and Japan in both Europe and Asia. Therefore, the appeasement policy of the United States towards Japan was also a rational result, with the aim of temporarily suspending direct conflicts with Japan and concentrating resources on contradiction with Germany.

Akira Iriye believed that after Japan invaded China, although Roosevelt continued Hoover’s non-recognition policy, he did not want to directly challenge Japan’s position. The president hoped to break out of the existing treaty and agreement framework and try something new. However, he did not show a serious inclination to boldly handle Asian affairs. Until the eve of the outbreak of the Pacific War, the Roosevelt administration was still unwilling to reconstruct the policy foundation of the United States in the Asia-Pacific region.[5]

Paul Kennedy and Paul Schroeder both analyzed the political situation of Britain since the 19th century and the domestic and international situation in Britain in the 1930s from a historical perspective. They concluded that the appeasement policy of Britain towards Germany at the Munich Conference was a continuation of Britain’s century old politic tradition, which is to maintain the balance of power in Europe and ensure the security of Britain as an island country.[6,7] Based on this, it be also believed that the United States’ policy of appeasement policy towards Japan in the 1930s was a continuation of the Anglo-American political tradition, aimed at supporting a great power in the Asia-Pacific region, balancing power relations in the region, and protecting US national security.

Their analysis is trying to prove that the United States is not preparing for war, but rather avoiding it. However, they all underestimated the influence of domestic politics, viewing certain crucial decisions of American decision-makers as accidental outcomes, while ignoring the role of structural factors in decision-making.

3. Taking retreat as progress

This paper argue that a country’s domestic politics can influence the international situation through foreign policies, and changes in the international situation can in turn affect domestic politics. Therefore, when national leaders are unable to overcome the opposition through domestic measures, he can change the international situation through the foreign policy, change domestic politic through the international situation, and shape a better domestic environment for policy implementation.

In terms of US Japan relations in the 1930s, Roosevelt wanted to go to war with Japan, but domestic isolationists hindered his efforts to prepare for war. Therefore, he implemented a policy of appeasement towards Japan, temporarily helping Japan expand and constantly stimulating its aggressive ambitions, causing American public opinion to shift towards a direction favorable to war preparation due to the perceived threat from Japan, thus paving the way for Roosevelt to implement war preparation.

In this section, a brief description of the new theory, encompassing its foundational principles and the underlying logic, will be presented. The new theory will also be compared with other existing theories. Empirical verification of the theory and demonstration of its explanatory power will be conducted in the subsequent section.

3.1. Theoretical foundation

This theory mainly discusses the domestic impact of appeasement policy, especially the influence of appeasement policy on the isolationist ideology in the United States. Generally speaking, foreign policy may be limited by domestic opposition. But at this point, leaders can use foreign policy to shape the international environment, and changes in the international environment can trigger changes in domestic politics, affecting the domestic environment and achieving an ideal foreign policy.

This theory is supported by many scholars. Steven Lobell believed that the pressure from the international system and the interactions between domestic political alliances determine how a country responds to challenges to its international status.[8] Robert Putnam pointed out that the complexity of domestic politics has a significant impact on international negotiations. International pressure also greatly affects domestic politics.[9] Jack Snyder proposed a theoretical framework to analyze how domestic political alliances affect a country’s foreign policy and international aspirations[10]. Peter Gourevitch explored how the international system and international national system affects domestic political structures and advocating that the international national system and international economy can influence domestic political development.[11]

The general theories and scholarly debates referred above form the intellectual foundation and rationale behind the following theory on the policy of appeasement.

3.2. Theory on appeasement

In the specific context of US-Japan relations during the 1930s, the confrontation between the United States and Japan emerged as the central theme of the Pacific situation. As Japan's influence in the Asia-Pacific region continued to expand and the power of militarism within Japan grew stronger, it became increasingly inevitable that greater disputes would arise between the two nations.

Led by President Franklin D. Roosevelt, the liberal internationalists in the U.S. administration were acutely aware of this looming conflict. They recognized that to counteract Japan's aggressive expansion, a fundamental solution would likely involve the use of military force. However, the domestic political landscape, particularly the prevailing sentiment of isolationism, posed significant challenges to the realization of their international agenda.

Consequently, the government of the United States adopted a policy of appeasement towards Japan. This strategy was designed to deceive the existing isolationists and to create an illusion of peace while actively shaping the international environment. By continuously altering the international landscape, especially by temporarily helping Japan expand and constantly stimulating its aggressive ambitions, the United States aimed to manipulate external circumstances in a way that would indirectly influence and shift domestic politics, mainly overcome the isolationist tendencies. This paved the way for the United States to implement measures to prepare for war, including supporting China's resistance, imposing sanctions on Japan, and restructuring its military.

This calculated approach was aimed at reversing the tide of isolationism within the United States. By doing so, the administration sought to prepare the nation for the eventuality of entering the war. The strategy hinged on the belief that a change in the international situation could galvanize public opinion and garner support for a more active and internationalist foreign policy.

In essence, the United States’ policy of appeasement towards Japan in the 1930s was a complex and multifaceted approach. It was not merely a passive response to Japan's aggression but a deliberate strategy to influence domestic politics through the manipulation of international affairs. This strategy underscored the administration's commitment to overcoming the constraints imposed by isolationist tendencies and to positioning the United States for a more active role in global affairs, ultimately leading to its involvement in the Second World War.

3.3. Counter argument

Undoubtedly, one of the problems with this theory is that implementing a policy of appeasement towards an expanding militaristic regime is a very dangerous policy. Once the crisis of the situation is not properly controlled, it will backfire and harm the United States’ core interests. So why did the United States still implement a policy of appeasement towards Japan?

Overall, this is because for the United States, Japan's threat is generally controllable, and it is also necessary to implement a policy of appeasement.

3.3.1. Controllable threats

Although implementing a policy of appeasement towards Japan may increase Japan’s power and fuel its threat to the United States, this threat can be controlled for the United States, mainly for four reasons.

Firstly, the industrial level and national resources of the United States were far stronger than those of Japan, and a large part of the materials needed for Japan’s aggressive war still had to be imported from the United States. The United States retained the ability to control Japan’s economic lifeline. Secondly, China was still persisting in its war against Japan’s aggression, holding back most of Japan’s war forces and preventing Japan from using its national strength to confront the United States in a short period of time. In addition, the Asia-Pacific region was not only dominated by the United States. Thirdly, western countries such as the United Kingdom, France, and the Netherlands have colonial interests in the region. If Japan wants to further expand in this area, it will inevitably provoke reactions from many other countries, putting greater international pressure on Japan and increasing the cost of Japan’s expansion. Fourthly, due to the protection of the Pacific Ocean, Japan's direct threat to the United States will be limited to the Western Pacific region and will not exceed the Hawaiian Islands and the Aleutian Islands at most. Therefore, the United States can control the threat from Japan at a distance far from its homeland.

3.3.2. Necessity

This measure was taken in a situation where domestic policies could not change the isolationist ideology, and adopting appeasement policies was a necessary outcome

As mentioned earlier, the Roosevelt administration envisioned the war against Japan, aimed at preventing the power balance in the Asia Pacific region from shifting in a direction unfavorable to the United States. The structural contradictions between the United States and Japan lead to the failure of other containment strategies, as the bellicose Japanese authorities resist all peaceful solutions to the problem. However, the domestic isolationist ideology has become an obstacle for the United States to prepare for preventive war. The many events that occurred after World War I have shown that changing the domestic isolationist trend solely from the perspective of domestic policies is doomed to be futile, and can only be changed by improving domestic politics through external factors. If the government adopts a relatively aggressive policy towards Japan, it will face a dual backlash both domestically and internationally: the United States will be forced to go to war with Japan if it cannot prepare enough for war, or will be impeached by isolationists. Therefore, adopting appeasement towards Japan became a necessary means: it would not provoke intense reactions from domestic isolationists, but could also stimulate Japan's aggressive ambitions, ultimately achieving the goal of going to war with Japan.

3.4. Summarize the differences

When juxtaposing the above theory against the existing theory, a stark contrast emerges in the interpretation of historical policy objectives. The avoid-war theory posits that the policy was aimed at circumventing war with Japan, with observable implications such as a lack of American preparedness for war with Japan, an unwillingness of the American people to engage in combat, and a conciliatory or compromising American stance up until the outbreak of war. These implications suggest a passive and peace-maintaining stance by the United States. Another theory suggests that the goal of the appeasement policy is to buy time for rearmament, with observable implications such as a reorganization of the United States’ military and a shift from appeasement to confrontation of the United States’ policy towards Japan.

In contrast, theory of this paper examines a policy objective with far-reaching implications: to transform the long-standing isolationist public sentiment in the United States through provocation of Japan. The causal logic behind this policy is meticulously orchestrated, with policymakers attempting to rile Japan through diplomatic or military actions, thereby stimulating nationalist sentiments among the American populace, reducing opposition to involvement in international affairs, and preparing for potential military conflicts.

As this policy is gradually implemented, several key societal and political changes can be observed. Firstly, the isolationist ideology in the United States experiences a significant transformation. This shift is reflected in the public's attitude towards international affairs, moving from non-intervention and disengagement to a more proactive and supportive stance towards government actions on the global stage.

Secondly, the domestic political landscape in the United States begins to evolve in a direction conducive to war preparedness. This is evident not only in the discussions and decisions among policymakers but also in the increase of defense budgets, the intensification of military training and readiness activities, and the heightened public awareness of national security threats. These changes reflect the nation's preparation for potential conflicts and its emphasis on protecting national security and interests.

Lastly, Japan's willingness to go to war with the United States significantly increases. This change may be a direct response to American provocations, indicating that Japan's foreign policy may become more aggressive, and the tension between the two countries could escalate. This heightened tension not only increases the risk of war but also poses a threat to regional stability and international peace.

These observable implications suggest that policymakers have adopted a complex and dynamic approach to foreign policy. They are not only preparing for potential military conflicts but also working to influence and shape public opinion. Although the implementation of such policies may appear conciliatory and compromising on the surface, there is a strategic depth to them, readying the nation for the possibility of war. The execution of this strategy provides people with a new perspective to reassess and understand the historical events and their outcomes, revealing the complex motives and objectives behind policy-making.

It is worth to be mentioned that unlike other views advocating a preparation for the war, the above theory holds that the direct purpose of appeasing Japan by the United States was to overcome the isolationist ideology within the country, rather than simply rearming its military. Rearmament is a measure that can only be taken after the isolationist ideology has been overcome, rather than the direct goal of appeasement by the United States.

4. Purpose of the United States’ policies towards Japan

In this section, the argument is presented that the purpose of the US appeasement policies towards Japan was to overcome domestic isolationist tendencies. This claim is supported by an examination of domestic isolationism, the policies of appeasement, Japan's response, the change in domestic attitude, and the development of new foreign policy and war preparations.

4.1. Isolationism tendencies

Anyone studying US Japan relations during this period would mention the powerful isolationist forces within the United States at that time. The history of isolationism in the United States can be traced back to the beginning of its founding. In George Washington’s farewell speech, he clearly stated that Americans cannot interweave the fate of the United States with Europe. The geographical location of the United States indeed provided convenience for this ideology, as the vast Atlantic Ocean could block any political turmoil and prevent the United States from being disturbed by the European revolutions and international disputes of the 19^th century. This remained unchanged during the Second Industrial Revolution, even as the United States’ influence spread across the entire American continent and even extended to Southeast Asia as far as the Philippines.

The outbreak of the First World War exacerbated the spread of isolationism. For the first time since its founding, the United States sent troops to Europe to participate in a global war. Although it laid the foundation for the United States to join the ranks of the five major powers at the Paris Peace Conference, the side effects were also evident: the US military paid a great price. The heavy losses and casualties in the war shook the United States of America and greatly increased the psychological aversion of the people to war. In fact, this isolationist ideology had a huge impact shortly after the end of the First World War, to the point where the US Congress decided to refuse to join the League of Nations created by President Woodrow Wilson.

By the 1930s, isolationism had reached its peak. Because of the painful memories of the First World War and the Great Depression, people are more willing to focus on domestic affairs rather than wars thousands of miles away. This trend of staying away from war was comprehensive. Any attempt to expand the US military and military industrial production was seen as increasing the likelihood of the US joining the war. In 1934, the isolationists established the Nye Commission to examine the rationale for United States' participation in World War I. The Commission held that the United States entered the First World War out of selfish interests rather than justice, and referred to politicians who supported joining the European war as ‘merchants of death’. This conclusion shows the actual attitude of the isolationists to the war, they believe that United States’ participation in war would bring another blood bath to the Americans and weaken the country.[12]

The isolationist political power was so great that Franklin Roosevelt, running for president in 1933, had to deny his early support for joining the League of Nations.[13] As a liberal internationalist, the rise of two fascist countries, Germany and Japan, could not help but make him feel anxious. He knew that not only will it inevitably trigger the next war sooner later, but it will also endanger the security of the United States. Therefore, the US must respond to the expansionist behavior of these two countries. However, his interventionism actions was inevitably constrained by isolationism. As president, he can choose interventionists similar to him to hold executive positions, but the power to declare war and finance still belongs to the elected Congress. As long as public opinion does not support war, his efforts are in vain.

The difficulties he faces were objective, as isolationists had significant influence in Congress, the Republican Party, and specific professional groups across various states in the United States.[12] Even in the ruling Democratic Party, isolationism remains the mainstream force. In a Gallup poll in December 1939, 48% of Democratic supporters surveyed believed that the Democratic Party was more likely to avoid war.[14] Nowadays, we cannot know exactly how many people has held an isolationist stance, but one thing is certain: until shortly after the breakout of the European war, avoiding war was a political correctness in the United States.

4.2. Policies of appeasement

The United States’ policy of appeasement towards Japan mainly existed in the form of non-interference. After the outbreak of the September 18 Incident in 1931, Japan directly occupied Northeast China. Faced with this action that directly threatened American interests, the Hoover administration did not make a substantial response at that time. In January 1932, US Secretary of State Stimson issued a series of notes and statements, which are known as “non-recognitionism” in history. On the surface, the United States warned Japan of its aggressive behavior and did not recognize Japan’s occupation of China, but did not take any practical steps to oppose Japan’s expansion. This policy, along with the ‘Lytton Report’ released by the League of Nations in the same year, is known as a representative of the United States’ early policy of appeasement towards Japan.[15]

President Franklin Roosevelt, who came to power in 1933, was the successor of President Wilson’s internationalist route, actively intervening in international affairs and striving for a better external environment for the United States. In order to confront Japan and Germany, the Roosevelt administration even put aside ideological grievances and established diplomatic relations with the Soviet Union. However, Roosevelt faced attacks from isolationists in his direct policy towards Japan. This became even more evident after Japan expanded its invasion of China in July 1937. Roosevelt delivered the famous ‘Isolation Speech’ on October 5,1937, in Chicago, the center of isolationist forces, advocating against treaty breaking actions that were causing international anarchy and instability.[16] This was strongly opposed by isolationists, and under their fierce attacks, Roosevelt had to temporarily compromise, telling reporters that the sanctions against Japan had “been abandoned”.

As the president of the United States, Roosevelt could not ignore the advancing Japanese Imperial Army and its potential harm to American interests. However, he cannot directly respond to Japan’s actions with Internationalist reactions due to the pressure of isolationists. This had led to a peculiar phenomenon: before the outbreak of the Pacific War, the United States’ policy towards Japan seemed contradictory, ostensibly condemning Japan’s actions but actually ignoring them. For China, which was experiencing Japanese aggression at the time, this was undoubtedly a form of appeasement. As a liberal internationalist, Roosevelt’s appeasement seemed unreasonable, but in fact it was his attempt to deal with isolationism. The purpose was clear: he wanted Americans to understand that isolationism was no longer appropriate in the present world.

The Roosevelt administration’s appeasement policy towards Japan was different from Britain’s appeasement policy towards Germany. It was mainly manifested as surface condemnation and actual indulgence. Japan launched a full-scale invasion of China with the aim of turning China into its exclusive colony. This inevitably damaged the privileges and interests of the United States. In order to take care of the feelings of China and neighboring countries, maintain the diplomatic reputation of the United States, and to some extent protect the interests of the United States in China, the US government had expressed opposition to Japan’s actions to the certain extent. After the Japanese army invaded North China, on December,1935, US Secretary of State Cornell Hull issued a statement accusing Japan of causing significant changes in the political status and situation of several provinces in northern China, posing a threat to US interests in these areas. Therefore, the US government was “closely monitoring what is happening in the region”.[17] Japan’s smuggling operations against China in 1936 also faced multiple protests from the US government.

However, during this period, the United States’ policy towards Japan was still dominated by compromise and indulgence. On July 12, 1937, the counselor of the Chinese Embassy in the United States informed the US State Department of the North China Incident and requested the United States to mediate. US Secretary of State Hull stated that the United States maintains a “fair and friendly attitude” towards both China and Japan. If the United States attempts to mediate, it will “anger” Japan. He hoped that both sides will exercise restraint and reject China’s demands.[18] On July 16th, he issued another statement, emphasizing the importance of maintaining peace, advocating for the abandonment of force, and renouncing interference in the internal affairs of other countries.[19] But the principles discussed in it were all abstract, cleverly concealing the essence of the Sino-Japanese issue and actually favoring Japan’s aggression against China. As expected, this statement was immediately welcomed by Japan.

In addition to politics, the United States also appeased Japan economically. The United States sent a large amount of strategic materials to Japan, providing convenience for Japan to expand its aggressive war. In 1938, the United States supplied nearly 44 percent of Japan’s imports and purchased 27.9 percent of Japan’s exports.[20] Most of the crude oil, copper alloys, scrap steel, car and parts used by Japan in the war against China were provided by the United States. These materials accounted for 58.8 percent of all American exports to Japan in 1937. In 1938, it was 66.3 percent. By 1939, this number had risen to an astonishing 81 percent. In the first half of 1937 alone, the United States exported as much as 13 million tons of scrap steel to Japan, and Japan imported 35 million barrels of American crude oil in the same year. Many strategic materials were transported to Japan, objectively playing a role in providing a blood transfusion to Japan and greatly assisting Japan in its aggressive war against China.

For businessmen, they can maintain world peace through trade and investment. This also means that they will not oppose the continued trade between the United States and Japan. In the memoirs of Secretary of State Cornell Hull, Under-Secretary of State Sumner Welles, Secretary of the Treasury Henry Morgenthau and Ambassador to Japan Joseph Grew, there was almost no record of direct protests by businessman against State Department policies. They were pleased with the neutral policy of the State Department, and the US government has not responded to this phenomenon.[21] On September 14, 1937, Roosevelt issued a statement, prohibiting US government merchant ships from transporting military supplies such as weapons and ammunition to both China and Japan. Private merchant ships transporting the aforementioned items should bear their own responsibility. This has brought great convenience to Japan. Because Japan is a naval power and has already blocked the coast of China at this time. In this situation, American private merchant ships heading to China would take risks, but heading to Japan would not take any risks. It can be seen that this measure is only beneficial to Japan.

The appeasement policy of the United States towards Japan basically continued until the second half of 1939 and early 1940, which actually strengthened Japan’s strength and stimulated its aggressive ambitions. Since then, Japan’s desire to challenge the United States had greatly increased.

4.3. Japan’s response

The conflict between the United States and Japan can be traced back to the period of the Russo-Japanese War, when Japan, which won the war, attempted to exclude American interests in Northeast China. After World War I, the political and economic power of both the United States and Japan was strengthened, laying the foundation for their imperialist expansion. However, the expansion of the two countries in the Asia-Pacific region inevitably led to conflicts. The Treaty of Four States and the Treaty on the Limitation of Naval Armaments, which were formed at the Washington Conference in 1921, were the main achievements of the United States in suppressing Japan's expansion. Japan's gains and losses in the Washington Conference are not worth it, which is unacceptable for Japan seeking expansion in the Asia Pacific region. Shortly after the conference, Japan regarded the United States as its top hypothetical enemy.

Although external expansion had always been the mainstream of Japan’s foreign policy, its internal political situation had been unstable. The two factions within the Imperial Japanese Army and Imperial Japanese Navy finally reached a consensus respectively in 1936 and 1933. Both factions in power advocated the use of force to change the international situation^.[22] With the gradual rise of the militarists, war between Japan and neighboring countries had become inevitable.

The appeasement policy of the United States towards Japan before and after the Second Sino-Japanese War greatly aided Japan’s aggression against China. The long-term export of military supplies from the United States to Japan had further widened the power gap between the already disparate Chinese and Japanese armies. This became one of the reasons why Japan expanded its aggression against China: originally, Japan’s military aggression in China was limited to the Northeast and North China regions, but after the July 7^th Incident in 1937, the Japanese army’s attack on China expanded to the entire northern and eastern coasts of China. In addition, Japan's aggressive policy towards China has also shifted towards a tough stance as a result. In 1935, the Japanese Hirota Koki Cabinet proposed to separate North China as a buffer zone for Manchukuo. This route was once halted by Sato Naotake and restored by Konoe Fumimaro in 1937.[22]

The United States had extensive interests in China, and Japan was once very wary of American power, as evidenced by the USS Panay incident. Although no stricter measure were taken, Washington’s protest against the Japanese government was very effective. Tokyo assuaged American sentiment by quickly issuing an apology and offering full compensation.[22] However, the image of external aggression and internal weakness displayed by the United States in its appeasement policy greatly boosted the confidence of Japan and the United States in going to war. Encouraged by the situation of the war against China, the Japanese Konoe Cabinet announced in November 1938 its commitment to establishing a "New East Asian Order", defining its military operations in Manchuria and the establishment of Manchukuo as a revision of the Washington system.[22] In addition, in terms of economy, Japan has taken many mandatory measures such as seizing customs, controlling foreign exchange, restricting trade, monopolizing operations, and monopolizing shipping to exclude and undermine the economic interests of the United States in China.[15]

This appeasement also strengthened Japan's determination to advance southward. After the outbreak of the European War, Japan issued a manifesto stating that the United States was the main obstacle to Japan's expansion and made demands on other Pacific powers. The second Konoe Cabinet, established in 1940, proposed that Japan must strengthen its political alliance with Germany, prepare for war against the United States and Britain, and solve the Southern issue. Guided by this program, on August 1^st, Japanese Foreign Minister Yokosuke Matsuoka proposed a plan to establish the “Greater East Asia Coprosperity Sphere”, with the vast East Asia and Southeast Asia region as far as Thailand as the goal of the plan. On the same day, Japan asked the French Vichy government to allow the Japanese army to establish air bases in northern French Indochina, and allow the Japanese invaders to pass through and use the airports. The "Nishihara-Martin Agreement," signed on September 4, 1940, allowed Japanese troops to be stationed in French Indochina, and the French authorities did not resist at that time. Subsequently, the Japanese 22nd Army issued an order to stop the offensive and withdraw troops, but on September 22, the Japanese Fifth Division crossed the border into northern Indochina and quickly captured important cities such as Lang Son and Dong Dang. On September 27, 1940, Japan signed an alliance treaty with Germany and Italy, attempting to use this treaty to strengthen its power in competing with the United States for Pacific hegemony. On November 12th, Japan forced the Dutch East Indies authorities to sign an oil and mineral export agreement, stipulating the export of 1.8 million tons of oil to Japan within the next six months; The export of strategic resources such as rubber, tin, bauxite, nickel ore, and scrap iron to Japan has also increased significantly compared to before.[15]

Overall, the US policy of appeasement towards Japan has strengthened Japan's power in a short period of time, creating a favorable situation for it in China and other places. This stimulated Japan's ambition and constantly challenged American interests. Under the challenge of Japanese aggression, public opinion in the United States began to shift towards breaking away from isolationism and supporting war preparations.

4.4. Change of domestic attitude

As time entered 1940, Japan's continued aggression spread throughout the United States through a developed information dissemination system. The American people were unwilling to intervene in wars in Europe and Asia, mainly because the interests of the United States will not be directly damaged by wars thousands of miles away. However, when Japan's expansion gradually developed, showing that it would directly challenge the authority of the United States and compete with the United States for hegemony in the Asia Pacific, especially when directly challenging the interests of the United States, American polls began to support the confrontation with Japan.

In 1939, in order to amend the Central Plains legislation and lift the arms embargo, Roosevelt requested a special session of Congress. At this time, polls showed that 60% of the public supported the motion to lift the arms embargo, over 80 percent sympathized with the warring Allied powers[23], and more than half of the public supported aiding Britain and France. In another Gallup poll in January 1940, 75 percent of the respondents supported banning arms sales to Japan. The February poll showed that as many as 79 percent of people supported Roosevelt’s increase in national defense spending.[14] On December 29, 1940, Roosevelt once again issued the “Fireside Chats” declaring that the United States “must become a great arsenal of democratic institutions”. This speech was in sharp contrast to the “isolation speech”, which was widely supported by the American people, 80 percent of whom were in favor, while only 12 percent were against it.

These polls showed that most American people have been widely opposed to the German Italian Japanese three axis at this time, and sympathized with the resistance struggle of people all over the world. This paved the way for a policy shift and war preparedness in the United States.

4.5. Changes of the foreign policies

After public opinion began to shift towards a direction favorable to war preparation, the policy changes in the United States were mainly reflected in three aspects.

Firstly, The United States increased their war support for China. On September 25, 1940, the United States announced a credit of $25 million to China. After the formation of an alliance between Germany, Italy, and Japan, the United States instructed Britain to reopen the Burma Road on October 17th. On November 30, Roosevelt announced another $100 million loan and 50 interceptor planes to China, and took steps to issue passports to all American pilots and flight instructors who volunteered to come to China.

Secondly, Roosevelt expanded the trade embargo against Japan. As early as July 1939, Roosevelt announced the abolition of the 1911 Japan US Commercial Treaty. On September 26, 1940, Roosevelt ordered a complete ban on exporting scrap steel to Japan and withdrew American investment in Japan. On December 10th, Roosevelt approved an embargo on iron ore, pig iron, steel, and steel products against Japan. By 1941, the conflict between Japan and the United States had further intensified. Japan ignored the warning of the United States and forcibly stationed in southern Indochina. Roosevelt then ordered the freezing of all Japanese assets in the United States on July 26. On August 1st, the United States announced a comprehensive embargo on Japan, prohibiting the export of oil to Japan.

Thirdly, during that period, President Roosevelt took steps to bolster the nation's military readiness. He increased the size of the army and ramped up the manufacturing of military aircraft. In a single day, July 10, 1940, Congress sanctioned an additional $5 billion for defense expenditures. Later, on August 27, legislative authority was given to Roosevelt, enabling him to mobilize the National Guard for active duty readiness. Further, on September 14, Congress enacted the nation's first-ever peacetime draft law, making all males aged 20 to 25 subject to the draft. When registration commenced on October 16, a staggering 16 million young men across the country signed up. In addition, the United States' war plan against Japan, the "War Plan Orange", was constantly revised in the late 1930s. Including beginning to attach importance to Guam's strategic position and enhancing military defense in the Philippines.[24]

5. Conclusion

The appeasement policy of the United States towards Japan in the 1930s was not aimed at avoiding war with Japan or directly buying time for rearmament, as traditional explanations assumed. In fact, the real purpose of the Roosevelt administration’s policy of appeasement towards Japan was to overcome domestic isolationist tendencies, to create a better domestic environment for war preparation.

Roosevelt realized that war between the United States and Japan was inevitable, and the strong domestic isolationist opposition prevented his preparations. The Sino-Japanese War and Japan’s expansion in the Western Pacific proved that brief concessions would not satisfy Japan’s expansionist nature, and Roosevelt did not expect this appeasement to lead to a long-term peace. He needed to take some measures to prepare for the outbreak of war, at least not to make the US defense force too weak, which required him to overcome the domestic isolationist trend as soon as possible. Therefore, for the United States, the policy of appeasement was a means of changing domestic political situations.

More generally, domestic politics is not always determined by domestic policies. When domestic policies cannot overcome the influence of the opposition, policymakers can influence the international situation by formulating foreign policies that are more easily accepted by the opposition, thereby changing domestic politics through the international situation.

To conclude, as an understudied case for appeasement, the US-Japan relationship in the 1930s is less valued than the Anglo-German relationship of the same period. Scholars need to look at the US-Japan appeasement from a different perspective of Anglo-German appeasement, as their domestic and international situations were not the same. In this case, a policy of appeasement was for the hidden agenda behind the facade, the ultimate goal was to change the domestic politics. Furthermore, this paper demonstrates that appeasement policy is one of the means by which national leaders influence international politics by changing the international environment. It provides space for further research on the effectiveness of appeasement policies, and also provides additional explanatory methods for the relationship between the international environment and domestic politics.