Though President Roosevelt was firmly convinced that an Axis victory would be disastrous, isolationism in Congress and the electorate compelled him to proceed with caution. In December 1940 Churchill told him of the damage done by German submarines, and warned that the time was approaching when Britain would not be able to pay for munitions. The Lend-Lease bill, introduced into Congress in January 1941, empowered the president to transfer any defense material to any nation whose defense he believed vital to United States’ interests. Although isolationists fought hard, the bill became law in March, and proved a key turning-point in US foreign policy.
Although the Thompson sub-machine gun was not an ideal military weapon (above), its American symbolism, arising from prewar gangster films, made it another propaganda coup. The British soon replaced it by the cheaper and lighter Sten, though it remained in limited service.