World War II Background
The Interwar Years, 1920-1939
Copyright © Henry J. Sage, 2010, 2017

In the aftermath of the Great War, as American troops came home from Europe, the United States became permeated by a sense of disillusionment as people observed the turmoil in Europe in the years following the terrible conflict. Americans turned away from international affairs as the roaring twenties swept over the nation.  The old Victorian ways went out as people embraced new feelings of freedom from the strictures of the past. Movies, radios, cheaper automobiles and new music were part of the new American landscape.  Through those years and the Depression years that followed America was focused inward. Then, in the late 1930s, America was forced to once more look outward.


United States Diplomacy in the 1920s: The Aftermath of the Great War

America’s participation in the First World War came relatively late. Nevertheless, by the time the war was over and President Wilson had participated in the writing of the Treaty of Versailles, America was more connected with the rest of the world than it had ever been before. The American acquisition of Puerto Rico, Guam, and the Philippine Islands as an outcome of the Spanish-American War and President Roosevelt’s sponsoring of the Treaty of Portsmouth also contributed to America’s new international standing. But Americans did not readily embrace their new position, feeling, as one U.S. Ambassador to Great Britain put it, that we were well out of the “European mess.”

The issues of ratification of the Versailles Treaty and America’s participation in the League of Nations were important in the election of 1920. The United States was still technically in a state of war with Germany into the Harding administration, but a joint resolution of Congress declaring an end to hostilities was followed by treaties negotiated by Secretary of State Charles Evans Hughes with Germany, Austria and Hungary in 1921. The separate question of America’s participation in the League of Nations remained a significant issue throughout the 1920s, and opinions were sharply polarized. President Harding, believing that his electoral majority of 7 million votes was a vote against American participation in the League, was in no mood to support the organization.

The question of whether American participation in the League of Nations would have had a significant impact on subsequent world events has been debated widely. Although it is impossible to say what impact such participation might have had, it is clear that the absence of the most powerful nation in the world detracted from the League’s ability to reduce any potential conflict. Whether World War II might have been averted is, of course, moot; nevertheless, the ease with which Hitler aroused the German people in order to carry out his aggressive foreign policy, along with the inability of the other nations of Europe to deter his threatening behavior, must be laid in part at the doorstep of American non-involvement. America’s powerful economy and potentially powerful military establishment might have served as an effective deterrent to aggression; instead, the United States chose disengagement while reducing her arms precipitously during the interwar years.

During those postwar years Great Britain struggled to regain a peacetime footing as her economy recovered from the terrible costs of the Great War. Northwestern France was in ruins, and political turmoil dominated the French nation for twenty years. Germany established the Weimar Republic, an experiment in democracy that might have succeeded in less turbulent times, but terrible inflation and a proliferation of small political parties kept the fledgling republic unstable. (Inflation in Germany during the 1920s far outstripped anything ever seen in America. Workers had to be paid twice daily, for their wages would be practically worthless after a few days, or even hours. In 1922-23 prices rose 18,000%.) The door was open for radicals who were quick to criticize the victorious nations for the humiliation of Versailles. Soon after the negotiations had closed in Paris, it became apparent that the peace achieved was really only an armistice; war was more than likely to erupt once more.

See section on “The Rise of Nazi Germany.”

The Washington Naval Conference. President Harding called the conference—the first international arms control conference in history—and Secretary of States Charles Evans Hughes convened the the opening session in November 1921, accompanied by congressional leaders. Nine major nation attended; the Soviet Union was not invited. In his opening address Secretary Hughes gave a candid speech in which he declared that “the way to this arm is to disarm,” and that the time to begin was immediately. Thus he proposed a 10 year holiday in the construction of capital ships—battleships and heavy cruisers—and he also recommended the scrapping of other ships. One British reporter claimed that Secretary Hughes had in 15 minutes “sunk more ships than all the admirals of the world have sunk over the centuries.” Although Hughes’s proposals were welcomed by many peace advocates, traditional naval powers such as Great Britain were less than enthusiastic. Nevertheless, the pressure for disarmament and avoidance of war was such that three important yreaties were agreed upon.

The Five-Power Naval Treaty was signed in February 1922 and was to remain in effect until 1936. It limited limit the ratio of capital ship tonnage among the five major powers: the United States (5), Great Britain (5), Japan (3), France (1.67), and Italy (1.67.) The treaty placed a limitation on the numbers and sizes of major warships, although it did not affect smaller vessels such as destroyers, submarines, and cruisers, but those vessels were limited to 10,000 tons displacement. The treaty called for a construction “holiday” of ten years. The aircraft carrier, which would become the dominant naval vessel of World War II, was still being developed and was not mentioned in the agreement.

The Four Power Treaty. The conference also agreed on a four-power treaty in which Great Britain, the United States, Japan, and France agreed to respect each other’s interests in the Pacific. It was an extension of an earlier Uited States treaty with Japan. Finally, the Nine-Power Treaty endorsed the Open Door policy in China. Those who signed it agreed to respect the “sovereignty, independence, and territorial and administrative integrity of China” and to uphold the principles of the Open Door. The Washington Conference was a landmark event, and it was followed by other attempts to reduce armaments and control the forces that tended to lead to war.

Locarno. In 1925 a meeting was held in Locarno, Switzerland, and was attended by representatives of Great Britain, France, Belgium, Italy, and Germany. Under the leadership of Gustav Stresemann, the German foreign minister, the meeting settled a number of security issues involving France, Belgium, and Germany. Germany also signed agreements with its eastern neighbors. Just as important was the so-called “Spirit of Locarno” that emerged, an indication that the major powers intended to try to settle future differences peaceably. Following the signing of the Locarno Pact, Germany was admitted to the League of Nations. Along with Friedrich Ebert, president of the German (Weimar) Republic, Stresemann showed great statesmanship. Unfortunately for Germany and the rest of the World, Hitler and the Nazis were on the rise in the 1920s.

The Kellogg-Briand Pact. The Washington Conference and the Locarno meeting made progress toward extended peace, and attempts to reduce armaments and corral the forces that tended to make war continued. In 1927 with rumblings of discontent in Germany, France approached the United States with a proposal that the two nations enter into a defensive alliance. It was an obvious attempt to provide protection in advance in case of German retaliation. Secretary of State Kellogg, not wanting the U.S. to become snarled in an alliance, suggested a wider pact that would “outlaw” war. The resulting Kellogg-Briand Pact was signed in 1928, though many realized that its goals were illusory; its intent was indeed to declare war illegal. One U.S. senator claimed it was “not worth a postage stamp”; another called it “worthless but harmless.” Nevertheless, the Pact was signed initially by fifteen nations, including France, the United States and Germany. It was eventually signed by 62 nations. (Kellogg-Briand Pact)

Further disarmament conferences were held at Geneva and London, and the League of Nations offered the possibility of defusing international tensions that might lead to war. But ultimately none of the agreements ever prevented anything significant. It was true that they were invoked from time to time to exert moral pressure on aggressive actions; in the end, however, it became apparent that moral force alone was of little use against dictators who had no qualms about violating or renouncing outright international agreements.

The Good Neighbor Policy. The United States had a history of intervention in Latin America going back to the time of Andrew Jackson in Florida, when it still belonged to Spain. Both Presidents Harding and Coolidge had to deal with growing “Yankee-phobia” south of the border. President Hoover rejected Wilson’s interventionist policies and went on a goodwill tour after the 1928 election. While giving a speech during the Sixth Pan-American Conference in Havana, he said, “We have a desire to maintain not only the cordial relations of governments with each other, but also the relations of good neighbors.” The Clark memorandum of 1930, formulated by Undersecretary of State J. Reuben Clark, rescinded the Roosevelt Corollary to the Monroe Doctrine.

The gradual removal of all American occupying forces  in Latin America soon began and was completed by 1934. The United States also renounced its right to intervene in Cuban affairs by terminating the Platt Amendment. Many problem areas still existed, and the United States had difficult issues to resolve with various individual nations, but the Good Neighbor policy improved relations enormously, so that by World War II the Western Hemisphere was reasonably unified, even though the United States was still seen as the “colossus of the North.”

In 1932 President Franklin Roosevelt affirmed the good neighbor policy in his inaugural address. He said he would “dedicate this Nation to the policy of the good neighbor—the neighbor who resolutely respects himself and, because he does so, respects the rights of others.” In 1936 Roosevelt attended the Buenos Aires Inter-American Conference. FDR’s address to the delegates was well received—he called himself a “traveling salesman for peace” and preached “mutual safety.” The Lima Declaration adopted at the International Conference of American  States in 1938 reinforced inter-American solidarity.

America in the 1930s: The Triumph of Isolationism: A “gloomy, pessimistic, negative pacifism.”

Henry L. Stimson was one of the most remarkable public servants in American history. He served in the Justice Department under Theodore Roosevelt and was William Howard Taft’s secretary of war. He served in World War I and later became governor general of the Philippines. Following that position he served as Secretary of State under President Herbert Hoover. He remained active in public affairs during the 1930s, and at age 73 he was appointed by President Franklin Roosevelt to be the Secretary of War, serving in that capacity until the war concluded in 1945. A lifelong Republican, he nevertheless worked harmoniously with men of both parties whom he respected and trusted.

stimsonIn his autobiography, On Active Service in Peace and War, written in 1947 with McGeorge Bundy, Stimson carefully outlined the events leading up to World War II, in which he was a vigorous participant and observer.

Unlike many who believed that the Kellogg–Briand pact was a useless exercise in paper diplomacy, Stimson argued that it gave moral force to the peace-loving nations and might have been used to resist aggression. Like virtually all observers, he found fault with the Treaty of Versailles and held France responsible for contributing to international tensions by refusing to ameliorate some of the treaty’s harsher provisions. Although he was a political opponent of Woodrow Wilson, Stimson argued that the failure of the United States to ratify the Treaty of Versailles, join the League of Nations or participate in the World Court contributed to the chaos of the interwar years. Stimson claimed that as the most powerful nation in the world, the United States could have been a force for good, but instead turned her back on the world and retreated into sterile isolationism.

The Rise of Imperial Japan. Henry Stimson claimed that the events leading up to World War II began with the Japanese incursion into Manchuria in 1931. Militarists in the Japanese Army had grown resentful of what they perceived as the westernization of Japan and vowed to return Japan to its traditional feudal samurai warrior culture. Seeking inroads into China, with whom Japan had had troubled relations for some time, army officers manufactured an incident in Manchuria. An explosion on a Japanese-owned railway was used as justification for the invasion of Manchuria, which Japan occupied. They renamed the territory the nation of Manchukuo under Japanese protection. Japan later bombed the city of Shanghai in retaliation for Chinese protests against the Manchuria invasion.

Secretary of State Stimson argued for a policy of non-recognition of any territorial acquisitions achieved by force. That policy, which became known as the Stimson Doctrine, was recognized by the League of Nations. In response, Japan withdrew from the League. In addition to her aggressive behavior toward China, Japan rejected the Nine Power Treaty, a reaffirmation of John Hay’s Open Door policy with regard to China, which was achieved during the Washington Conference of 1922. Thus, while the great democracies blindly pursued their own self interests, the fascists and militarists in Germany, Italy, Spain, and Japan were allowed to pursue their courses more or less unmolested. Thus they gained encouragement for their aggressive policies which ultimately led to the terrible holocaust of World War II.

Although Simpson as a conservative Republican found much he did not like in Franklin Roosevelt’s New Deal, he nevertheless established cordial relations with the incoming Secretary of State Cordell Hull and with President-elect Roosevelt during the transition months of 1932-33. He maintained that good relationship with Secretary Hull through 1940, when the president wisely chose him as Secretary of War, along with another Republican, Frank Knox, as Secretary of the Navy. Although both men were criticized by some members of their party for participating in a Democratic administration, both of them placed duty to country above politics and served their commander-in-chief with remarkable loyalty and distinction, thus contributing heavily to the successful prosecution of the war.

During the crisis years of 1931–1939, Americans found themselves in the depths of the Great Depression and did not want to think of further war, so the country retreated into a deeper position of isolationism. Americans saw themselves as “innocent bystanders” in world affairs and began to feel as trouble arose in Europe that America’s participation in the First World War may have been a waste. In 1933 the United States finally recognized the Soviet government and established formal relations with the U.S.S.R—primarily for business reasons. By 1936, as Hitler was beginning to menace Europe, Americans wanted to stay out of it, but how? Former Secretary of State Henry Stimson claimed: “The only sure way to stay out of war is to prevent it.” But how was the United States, which had refused even to join the League of Nations and had reduced its armaments to a dangerously low level, supposed to accomplish that?

The Nye Committee Hearings. In 1934 Senator Gerald Nye of North Dakota began a series of hearings that tried to show that munitions makers had made “huge” profits during World War I and were therefore somehow responsible for America’s involvement in the conflict. They were called the “Merchants of Death.” Arms manufacturers called to testify readily admitted that they had made large profits during war, wondering in the process why anyone should find that surprising. Although the results of the Nye Committee investigation were inconclusive, the isolationists nevertheless won the day; several Neutrality Acts were the result. The Committee also concluded that American freedom of the seas doctrine had become unreasonable because of the submarine. Neutrals, they concluded, should keep out of war zones and not traffic with nations at war.

The Neutrality Acts. As the hearings went forward, the isolationists firmed up their positions. Reading the political winds, President Roosevelt asked the Nye Committee to prepare legislation, which Congress subsequently passed. The Neutrality Act of 1935 forbade sale of arms to belligerents. Civilians would enter war zones on belligerent ships at their own risk. FDR signed the bill in August 1935. The arms embargo on all nations portion of the bill was opposed by FDR because it made it impossible for the U.S. to influence the action. The Act was nonspecific on trade. Cordell Hull called it a “moral embargo,” but there were problems in execution of the Act. The Neutrality Act was invoked in 1935 when Italy invaded Ethiopia. No citizens of neutral countries were allowed on belligerent ships. Italy was insulted. Historian A. J. P. Taylor said of that action: “Fifty two nations opposed Italian aggression, and all they accomplished was that Haile Selassie lost all of his country [Ethiopia] instead of only half.”

Lesson learned: Don’t go around insulting belligerents when trying to stay out of war. Half-hearted sanctions make things worse, a lesson that may be useful in more modern conflicts, whether in actual wartime or not.

Further neutrality acts were passed in 1936 and 1937, and the net result of those laws was to handcuff the United States, even if it had a legitimate desire to assist nations that were victims of international aggression. President Roosevelt made no attempt to block this legislation, but refused to invoke the laws when Japan invaded China, thereby allowing China to buy arms from the United States.

The Lure of Pacifism and Isolationism

When Americans looked back back at World War I and judged it a meaningless effort, many Americans sought security in pacifism or isolationism as well as in legal neutrality. They wanted a way to ensure that the United States would not be drawn into another European conflict. From the nYe Committee hearings and newspaper editorials most Americans suspected that they had been duped by the politicians, munitions makers, and bankers into going to war in 1917, and resolved never again to fight a meaningless war. Romantic notions of pacifism were not exclusive to the United States; in Great Britain college students pledged that they would never again fight in any kind of war. (Many of those same young men would die during World War II.)

A gradual breakdown of attempts at international cooperation developed as militaristic nations asserted their will with no regard for consequences or for maintaining the peace—conquest and revenge were their motives. The concept of collective security was, in effect, the same idea as the old “Concert of Europe.” Yet the toothless League of Nations brought nothing but head-in-the-sand optimism, not action. Aggressor nations ignored the League.

The isolationist impulse of the 1930s had various roots. One was that the Depression had been caused by World War I. The Bankers and “merchants of death” had dragged America into the conflict, which had left Europe in economic chaos, which in turn spread to the rest of the world. Thus America’s entry into the war had been a tragic mistake, as demonstrated by the political turmoil in Europe during the 1920s and 1930s. Although the United States had suffered relatively few casualties during the Great War, the magnitude of the carnage was widely known. The answer for many was pacifism, whose appeal was understandable. Unfortunately, American pacifism on the 1930s was hardly a deterrent to military aggression elsewhere in the world.

Chief reasons for isolationism:

  • Belief that the depression had been caused by W.W.I.
  • Belief that Europe was unworthy of our support
  • Pacifism—people who hated and abhorred war
  • Belief that arms manufacturers, bankers had caused war
  • Belief that W.W.I. had been a tragic mistake for the U.S.

Further events leading to World War II:

In 1936 the 1935 Neutrality Act was extended to 1 May 1937 and forbade loans or credits to belligerents. Again, the action hindered attempts by President roosevlt to influence affairs in Europe. On August of that year The president made a strong speech at Chautauqua, New York. In the speech he referred to his visits to the front lines during World War I and claimed, "I hate war." In the speech he held out for discretionary power, but his words still pleased the isolationists. The American people felt (correctly, as it turned out) that Europe was going to go up in flames and that America should stay out. Foreign leaders criticized America's position, but France and Great Britain did very little to avoid the war that many people saw coming.

Link to FDR Chautauqua Speech, 1936.

In 1937 a new neutrality act restricted arms sales, prohibited travel and neutral ships, and forbade arming of American merchantman. The cash and carry provision of the act on items other than munitions allowed profit-taking by exporters without getting involved overseas. The president was granted considerable discretion to list other items not affected. The neutrality act was never invoked against Japan because they never declared war on China. By not invoking the neutrality act President Roosevelt in effect aided China, but he also helped Japan because of their large merchant marine.

The year 1937 was the peak year of American isolationism. A Gallup poll reported that 94% of Americans said that we should keep out of foreign wars rather than try to prevent foreign wars. A widespread boycott of Japanese goods followed their incursion into China. A constitutional amendment was proposed that would require declarations of war to be approved by a referendum, except in case of actual invasion by a foreign power.

By late 1937, President Roosevelt was struggling to find a way to influence the events unfolding both in Asia and in Europe. Germany and Italy were behaving aggressively and were threatening world peace, but there was no question of which side the United States would eventually support. President Wilson had faced that dilemma when world war broke out in 1914, but the German decision to use unrestricted submarine warfare along with the Zimmerman telegram settled the issue for Wilson. Roosevelt clearly wanted to help the nations that were victims of aggression, but he also needed to keep the antiwar contingent in the United States at arms length. But Hitler's belligerence, his rejection of the restrictions of the Treaty of Versailles, his rearming of Germany, and his militant rhetoric, along with the participation of Italy and Germany and the Spanish civil war and the Italian invasion of Ethiopia, made it clear that if there was to be an enemy, it would be a fascist states of Germany and Italy.

Still, the spirit of isolationism was strong in the United States. The American military establishment was pitifully small, and the neutrality acts that Congress had recently passed limited America's ability to support nations with whom President Roosevelt was sympathetic. His quarantine speech was a step in the direction of taking a position that made it clear on which side the United States stood but at the same time was not warlike enough to arouse Roosevelt's political opponents.

Link to President Roosevelt's Quarantine Speech.

The next section will discuss events leading up to December 7, 1941, and America's entry into the war, some 2 years and 3 months after it had begun in Europe. The “America First” movement, arguing that the United States should not become involved in Europe's mess, disappeared almost instantly, and within hours of the Japanese attack, young men were flocking to the recruiting stations.

America Enters the War

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