Most Americans condemned German aggression and favored Britain and France, but isolationism remained powerful. Roosevelt feared that if Congress did not repeal the arms embargo mandated by the Neutrality Act of 1937, France and Britain would soon succumb to the Nazi onslaught. “What worries me,” Roosevelt wrote a friend, “is that public opinion . . . is patting itself on the back every morning and thanking God for the Atlantic Ocean (and the Pacific Ocean)” and underestimating “the serious implications” of the European war “for our own future.” Congress agreed in November 1939 to allow belligerent nations to buy arms, as well as nonmilitary supplies, on a cash-and-carry basis.

In practice, the revised neutrality law permitted Britain and France to purchase American war materiel and carry it across the Atlantic in their own ships, thereby shielding American vessels from attack by German submarines lurking in the Atlantic. Roosevelt searched for a way to aid Britain short of entering a formal alliance or declaring war against Germany. Churchill pleaded for American destroyers, aircraft, and munitions, but he had no money to buy them under the prevailing cash-and-carry neutrality law. By late summer in 1940, as the Battle of Britain raged, Roosevelt concocted a scheme to deliver fifty old destroyers to Britain in exchange for American access to British bases in the Western Hemisphere, the first steps toward building a firm Anglo-American alliance against Hitler.

While German Luftwaffe (air force) pilots bombed Britain, Roosevelt decided to run for an unprecedented third term as president in 1940. But the presidential election, which Roosevelt won handily, provided no clear mandate for American involvement in the European war. The Republican candidate, Wendell Willkie, a former Democrat who generally favored New Deal measures and Roosevelt’s foreign policy, attacked Roosevelt as a warmonger. Willkie’s accusations caused the president to promise voters, “Your boys are not going to be sent into any foreign wars,” a pledge counterbalanced by his repeated warnings about the threats to America posed by Nazi aggression.

Once reelected, Roosevelt maneuvered to support Britain in every way short of war. In a fireside chat shortly after Christmas 1940, he proclaimed that it was incumbent on the United States to become “the great arsenal of democracy” and send “every ounce and every ton of munitions and supplies that we can possibly spare to help the defenders who are in the front lines.”

In January 1941, Roosevelt proposed the Lend-Lease Act, which allowed the British to obtain arms from the United States without paying cash but with the promise to reimburse the United States when the war ended. The purpose of Lend-Lease, Roosevelt proclaimed, was to defend democracy and human rights throughout the world, specifically the Four Freedoms: “freedom of speech and expression . . . freedom of every person to worship God in his own way . . . freedom from want . . . [and] freedom from fear.” Lend-Lease started a flow of support to Britain that totaled more than $50 billion during the war, far more than all federal expenditures combined since Roosevelt had become president in 1933.

Stymied in his plans for an invasion of England, Hitler turned his massive army eastward and on June 22, 1941, sprang a surprise attack on the Soviet Union, his ally in the 1939 Nazi-Soviet nonaggression pact. Neither Roosevelt nor Churchill had any love for Joseph Stalin or communism, but they both welcomed the Soviet Union to the anti-Nazi cause. Both Western leaders understood that Hitler’s attack on Russia would provide relief for the hard-pressed British. Roosevelt quickly persuaded Congress to extend Lend-Lease to the Soviet Union, beginning the shipment of millions of tons of trucks, jeeps, and other equipment that, in all, supplied about 10 percent of Russian war materiel.

As Hitler’s Wehrmacht raced across the Russian plains and Nazi U-boats tried to choke off supplies to Britain and the Soviet Union, Roosevelt met with Churchill aboard a ship near Newfoundland to cement the Anglo-American alliance. In August 1941, the two leaders issued the Atlantic Charter, pledging the two nations to freedom of the seas and free trade as well as the right of national self-determination.