Museum of Science and Industry

U.S. Neutrality and the Lend-Lease Act

The U.S. remained neutral for the first year and a half of the war. Then, on March 11, 1941, U.S. President Franklin Delano Roosevelt signed the Lend-Lease Act, authorizing U.S. ships to carry supplies across the Atlantic Ocean to Britain and other countries fighting the Axis Powers. Hitler had ordered his forces to destroy supply lines to Britain, but he expressly forbade the sinking of American ships—hoping to keep the U.S. out of the war for as long as possible. 

Japan Attacks the U.S.

On December 7, 1941, Japanese planes and submarines carried out a devastating surprise assault on the U.S. Navy base in Pearl Harbor, Hawaii. The U.S. declared war on Japan the next day. On December 12, 1941, Germany and Italy declared war on the U.S. The Atlantic was no longer safe for American ships.