Isolation after World War I

In 1938, twenty years after World War I had ended, 70% of Americans polled believed that the United States' participation in that war had been a mistake. The United States had only been involved in the final nineteen months of the bloody conflict, between April 1917 and November 1918. But the war and the influenza epidemic that immediately followed resulted in the deaths of more than 116,000 American soldiers.

After the Paris Peace Conference in 1919, President Woodrow Wilson lobbied extensively for US support for the League of Nations, believing that an international representative body would prevent future wars. The US Senate, however, refused to approve participation in the League. The United States never joined the League of Nations, nor ratified the Treaty of Versailles.

In the 1920s, the US government took measures to reduce the threat of foreign conflict. The US signed treaties limiting naval construction, and signed the Kellogg-Briand Peace Pact, outlawing aggressive war. The United States also sought to lessen foreign influence by reducing immigration. The Emergency Quota Act of 1921 and the Johnson-Reed Act of 1924 limited overall immigration and set country-specific quotas. These laws privileged immigrants from northern and western Europe, and discriminated against those from southern and eastern Europe where there were large Jewish and Catholic populations. This marked the end of a period of mass immigration to the United States. The number of arrivals immediately fell to less than 20% of the pre-World War I totals.


International unrest in the 1930s, including Japan’s occupation of Manchuria, Italy’s invasion of Ethiopia, Nazi Germany’s remilitarization and territorial seizures, and the outbreak of the Spanish Civil War, threatened US isolationism. In response to these conflicts, the US Congress passed a series of Neutrality Acts, designed to prevent American involvement in these conflicts. Longstanding diplomatic practice held that countries unwilling to become involved in a conflict had to maintain strict neutrality; even economic sanctions, or selling arms to one belligerent but not the other, could be considered acts of war. The Neutrality Acts, therefore, defined the terms of American neutrality to the world.

The Neutrality Act of 1935 prohibited exporting arms and ammunition to any foreign nation at war. In 1937, a new neutrality act prohibited Americans from traveling on ships owned by any belligerent nation, and declared that American-owned ships could not carry any arms intended for war zones. At Roosevelt’s request, however, the Neutrality Act of 1937 removed impartiality, allowing the President to distinguish among nations at war when enforcing neutrality. Favored nations could purchase non-military products in the United States, provided they paid with cash and transported the goods on their own ships, an arrangement known as “cash and carry.”

Cordell Hull signs neutrality proclamationOn September 1, 1939, Germany invaded Poland, leading Great Britain and France to declare war on Germany. Americans who were polled immediately after the war began overwhelmingly hoped for the defeat of Germany, but more than ninety percent opposed getting involved in the war. A majority did not want to join the fight even if Nazi Germany defeated Great Britain and France.

In November 1939, two months after the beginning of World War II, Congress passed the Neutrality Act of 1939, which lifted the 1935 arms embargo and placed all sales to belligerent nations on a “cash and carry” basis.

The America First Committee and other Non-Interventionist Groups

Numerous groups advocated against American involvement in World War II. Some, like the National Council for the Prevention of War (founded in 1921 to promote neutrality) and Keep America Out of War Congress (founded in 1938 to oppose Roosevelt’s foreign policy), predated the war. Others united multiple constituencies after the war began to lobby more effectively. Mothers who did not wish to send their sons to war, Americans of German or Italian descent, Americans of Irish descent (who opposed helping Great Britain), socialists, students, pacifists, and a host of prominent businessmen, intellectuals, and average citizens took action to prevent US intervention. Though more Republicans than Democrats advocated non-intervention, these groups were not split along partisan lines. Many antiwar advocates did not appreciate the term “isolationist” commonly used to describe them. They often argued for a strong national defense and broad economic spheres of influence, even as they tried to persuade the United States to stay out of the war.

The largest and most influential non-interventionist group was the America First Committee, founded in September 1940 by a group of Yale University law students. The students, led by R. Douglas Stuart Jr., gathered prominent Americans to serve on the organization’s board, including: the president of the American Olympic Committee Avery Brundage; Hormel Foods chief executive Jay Hormel; Ford Motor Company founder Henry Ford; late President Theodore Roosevelt’s daughter Alice Roosevelt Longworth; and General Hugh Johnson, who had been the director of the National Recovery Act, one of President Franklin Roosevelt’s early New Deal programs. Democratic senator Burton Wheeler (Montana), and Republican senators Gerald Nye (North Dakota) and Robert Taft (Ohio) also served as important spokesmen for the organization.

The America First Committee (AFC), which may have had some 800,000 members and at least 450 local chapters, encouraged civic engagement, such as letter-writing campaigns to elected officials, and sponsored rallies and speeches throughout the country. Charles Lindbergh, who achieved international fame in 1927 for piloting the first solo nonstop flight across the Atlantic Ocean, became the committee’s most prominent speaker. Even before AFC’s founding, Lindbergh had given radio speeches opposing US involvement in the war and warning of Germany’s military superiority. During a September 11, 1941, speech in Des Moines, Iowa, Lindbergh warned listeners that “the Jewish people” had too much influence on American media and government and were “war agitators.” Newspapers throughout the country denounced Lindbergh’s speech as antisemitic. Even though the America First Committee did not officially promote antisemitism, the organization tolerated these sentiments among its members.

Interventionist Groups

In contrast to non-interventionist or isolationist groups, interventionist groups often advocated a variety of different policies, but generally agreed that the United States should actively support the Allied war effort economically and militarily.

The Committee to Defend America by Aiding the Allies (CDAAA) was founded in May 1940 by William Allen White, a prominent Republican publisher in Kansas, and was directed by Clark Eichelberger, the head of the League of Nations Association. The CDAAA, which ultimately boasted 750 local chapters and an estimated membership of 750,000, staged rallies and performances, took out full-page newspaper ads, and handed out flyers in an effort to gain support for aiding Great Britain. After Nazi Germany invaded the Soviet Union in June 1941, the committee dropped “by Aiding the Allies” from its name since many members opposed communism.

Fight for Freedom (FFF), founded in April 1941 and headed by journalist Ulric Bell, aggressively advocated entering World War II to defend both Great Britain and democratic values. Fight for Freedom had many prominent supporters, including journalists, writers, movie stars, and politicians. Walt Disney Studios produced a program cover for a FFF rally featuring Mickey Mouse, Donald Duck, and Goofy.

The Committee to Defend America and Fight For Freedom frequently worked together, and often coordinated with Roosevelt’s aides or British propagandists to rally public support. These organizations also informed Americans that the Axis powers were murdering civilians in the countries they occupied. In November 1941, for example, the CDAAA sponsored rallies throughout the country, protesting the Nazi regime’s mass murder campaign.

Destroyers for Bases

On May 10, 1940, Winston Churchill became the prime minister of Great Britain. Five days later, he cabled President Franklin D. Roosevelt to explain that the British military was in serious trouble. Churchill asked the United States to support Great Britain with all aid short of declaring war, including providing older naval destroyers, new aircraft, and anti-aircraft equipment. After several months of negotiations, Roosevelt announced the “destroyers for bases” deal on September 2, 1940, exchanging 50 old destroyers for a 99-year lease to place American military bases on British-controlled territory in Canada and the Caribbean. This deal was one in a series of important measures that helped tilt the United States from a policy of isolation from world affairs to intervention in the war against the Axis powers.

The Committee to Defend America by Aiding the Allies produced and distributed flyers proclaiming “Destroyers Today or Destruction Tomorrow.” The St. Louis Post-Dispatch, published by non-interventionist Joseph Pulitzer, called Roosevelt a dictator committing a war crime: “If this secret deal goes through...we all may as well get ready for a full-dress participation in the European war.”

Peacetime Military Draft

Four days after Roosevelt announced the “destroyers for bases” deal, Congress approved the Selective Training and Service Act of 1940. The act, which instituted the first peacetime military draft in US history, required men between the ages of 21 and 36 to register for the draft. The number of selected draftees was capped at 900,000 men, who would be enlisted for one year of training and service, and could only serve in the Western Hemisphere or in US territories.

Though there were anti-draft protests on college campuses nationwide, in December 1940, 78% of Americans polled favored the military draft.

1940 Presidential Election

In July 1940, the Democratic Party nominated President Franklin Roosevelt for an unprecedented third term in office. His opponent, Republican nominee Wendell Willkie, agreed with Roosevelt that the United States should lend active assistance to Great Britain. As the election drew closer, Willkie began to give speeches warning Americans that a vote for Roosevelt was a vote for entering the war. As the polls narrowed in the weeks prior to the election, Roosevelt told voters that, “We will not participate in foreign wars and we will not send our army, naval or air forces to fight in foreign lands outside of the Americas except in case of attack.” Ultimately, Roosevelt won reelection with fifty-five percent of the popular vote and an electoral college victory of 449-82. With the election behind him, FDR was able to take more decisive actions during his third term to prepare the United States for war.


In December 1940, Churchill informed Roosevelt that Britain would soon run out of cash to pay for transporting necessary war supplies. In response, Roosevelt told Americans during a fireside chat on December 29 that the United States “must be the great arsenal of democracy,” putting every effort towards manufacturing planes, ships, guns, and ammunition for Great Britain. “The sole purpose” of supplying Great Britain, he reassured them, “is to keep war away from our country and our people.” But by the time FDR began his third term in 1941, fewer Americans believed the United States would be able to keep out of war.

In January 1941, Roosevelt’s Congressional allies introduced HR 1776, a bill which granted the president the power to “sell, transfer title to, exchange, lend, lease, or otherwise dispose of...any defense article” to another country. America First Committee members referred to HR 1776 as the “War Dictatorship Bill,” but most Americans knew it as “Lend-Lease” for short. Polls showed that 68% of Americans approved of the lend-lease proposal. However, the Chicago chapter of the America First Committee claimed to have collected 700,000 signatures and 328,000 protest telephone calls in opposition of “the dictator bill." Despite the efforts of non-interventionists, the bill passed easily, and Roosevelt signed Lend-Lease into law on March 11, 1941.


After Lend-Lease passed and American factories began to convert their operations to war-related manufacturing, interventionist and non-interventionist groups argued over the US role in transporting war supplies to Europe. After President Roosevelt declared an American-controlled security zone around the East Coast, non-interventionists charged him with baiting German submarines and secretly hoping for an attack that would force the United States into war. 

Public opinion polls between 1939-1941 consistently showed that Americans did not favor declaring preemptive war on Germany, but they also revealed that Americans changed their priorities over time. In May 1940, 60% of Americans believed that keeping out of war was more important than aiding Great Britain, but by November 1941, 68% said that aid to Britain was more important. In essence, the American public understood by late 1941 that it would have to go to war to help defend Britain against Nazi Germany. Yet it was ultimately an attack by Japan, a member of the Axis Alliance and thus an ally of Nazi Germany, that ended Americans’ debate about whether to intervene in the war.

America Attacked

Japan attacks Pearl Harbor On December 7, 1941, the Imperial Japanese Navy launched a surprise aerial assault on the US Pacific fleet at Pearl Harbor, Hawaii, destroying eight battleships, numerous other boats and planes, and killing 2,400 Americans. The next day, the United States declared war on Japan but not on Germany. Three more days passed before Nazi Germany declared war on the United States on December 11. President Roosevelt was able then to portray war against both Japan and Germany as defensive measures.

The vast majority of Americans rallied to defeat the Axis powers as soon as the United States entered World War II. Most of the student-founders of the America First Committee and its military-age supporters joined the US military; the organization formally voted to disband on December 10, 1941. Only days after the United States entered World War II, no mainstream isolationist movement remained. As President Roosevelt told Americans two days after the attack on Pearl Harbor:

“We are now in this war. We are all in it—all the way.”