Conditions in Europe rapidly deteriorated between 1936 and 1939. In March 1936, Germany violated the Treaty of Versailles and reoccupied the Rhineland. In November 1937, Italy joined Germany and Japan in the Anti‐Comintern Pact,
which united the three countries against the Soviet Union. Germany then annexed Austria in March 1938 and, at the Munich Conference
in September 1938, Great Britain and France agreed to give Germany the German‐speaking part of Czechoslovakia (the Sudentenland) in return for “peace in our time.” By March 1939, Hitler annexed the rest of the country, and an independent Czechoslovakia ceased to exist. The August 1939 signing of the Nazi‐Soviet Nonaggression Pact,
in which Germany and the Soviet Union agreed not to attack each other, gave Germany a green light to invade Poland on September 1. This aggression in turn caused Great Britain and France, who had formed a military alliance with Poland that guaranteed Poland's independence, to declare war on Germany on September 3. The Second World War had begun.
American response to the war. Although Roosevelt quickly announced that the United States would remain neutral, he did not ask the American people to be neutral in thought, as Wilson had done in 1914. Although most Americans still wanted to stay out of the war, they had little sympathy for Nazi Germany or Fascist Italy. Americans' attitudes were reflected in the change of policy that occurred with the Neutrality Act of 1939, which repealed the 1935 arms embargo on belligerents and provided for the export of military equipment on a cash‐and‐carry basis.
In the spring of 1940, after a seven‐month lull known as the Phony War, the German army began its march again. Denmark and Norway were invaded in April, the Netherlands, Belgium, and Luxembourg fell in May, and France sued for peace in June. Any pretense of American neutrality ended as Great Britain stood alone. Defense spending and military production accelerated, with the focus on airplanes and motorized equipment. In September, Britain and the United States entered into the “destroyer‐naval‐base deal” — the exchange of 50 aging American destroyers for leases to British naval and air bases in Newfoundland, Bermuda, and British Guiana. The first peacetime draft was provided for in the Selective Training and Service Act, which registered men between the ages of 21 and 35 and planned to train more than 1.2 million troops and 800,000 reserves within a year.
The election of 1940. Germany's aggression and British requests for aid convinced Roosevelt to be “drafted” by the Democrats to run for an unprecedented third term. Even anti‐New Deal Democrats believed the president was the best person to respond to the volatile international crisis. To give his foreign policy a more bipartisan appeal, Roosevelt appointed Republicans Henry Stimson and Frank Knox to Secretary of War and Secretary of the Navy, respectively, in June 1940. Meanwhile, the Republicans nominated Wendell Willkie, a young, wealthy New York businessman, who had voted for Roosevelt in 1932. Both Roosevelt and Wilkie were internationalists who supported military preparedness and advocated providing as much assistance to Great Britain as possible. They also repeatedly stressed a determination to keep the United States out of the war. Diehard isolationists believed that Roosevelt's and Wilkie's internationalist outlook would eventually drag the country into another European conflict. The America First Committee, whose most noted spokesperson was aviator Charles Lindbergh, argued that a Nazi victory would not directly threaten U.S. national security. American public opinion, however, strongly favored backing the British “in their finest hour.” Although the popular vote was the closest since 1916, and Willkie ran considerably better than either Hoover or Landon, Roosevelt won an easy electoral victory, 449 votes to Wilkie's 82.
The “arsenal of democracy.” In a fireside chat after the election, Roosevelt called on Americans to become the “arsenal of democracy” — remaining out of the war but giving the British what they needed to fight. To implement this idea, he submitted the lend‐lease bill to Congress in January 1941. It gave the president the authority to lend, lease, sell, transfer, or exchange military equipment and other supplies to any country whose defense was deemed vital to American security. Although the isolationists opposed the legislation, the Lend‐Lease Act passed the House and the Senate in March, and the initial appropriation of seven billion dollars went primarily to Great Britain. Not long after the unexpected German invasion of Russia in June 1941, lend‐lease aid was also extended to the Soviet Union. During the spring and summer of 1941, the United States steadily prepared itself for the possibility of war. Providing direct aid to the British and the Russians meant transporting supplies on merchant ships across the Atlantic Ocean. Because German U‐boats (submarines) sank millions of tons of shipping during the Battle of the Atlantic in 1941, the U.S. Navy began escorting ships further from American shores. American troops were sent to both Greenland and Iceland to forestall Germans from occupying and using these locations as bases of operations against the Western Hemisphere. British and American military planners met secretly to map out strategy for the war, agreeing that if both countries were fighting Germany and Japan, the defeat of Germany would take precedence. In August 1941, in a more public show of solidarity, Roosevelt and British Prime Minister Winston Churchill issued the Atlantic Charter, a joint statement of their war aims that called for self‐determination, free trade and freedom of the seas, equal access to raw materials, and a new system of collective security.
By the fall of 1941, the United States and Germany were already fighting an undeclared naval war in the Atlantic. When a German submarine fired upon an American destroyer in September, Roosevelt ordered the Navy to “shoot on sight” any enemy warships in the western Atlantic. After the destroyer Reuben James was torpedoed on October 31 with the loss of 115 lives, Congress approved the president's request to arm merchant ships and to allow them to sail through combat zones to the ports of belligerents. The sinking of the Reuben James effectively scrapped the Neutrality Acts, and any further incident could have led to a formal declaration of war against Germany.