President Roosevelt, who favored U.S. intervention in WWII, advocated creating the program as a way to provide indirect support for the Allies without engaging the U.S. in a war for which there was not yet overwhelming public support.

Why was the Lend-Lease Act necessary?

The lend-lease program provided for military aid to any country whose defense was vital to the security of the United States. The plan thus gave Roosevelt the power to lend arms to Britain with the understanding that, after the war, America would be paid back in kind. ... and 37 other countries.

How did the Lend-Lease Act benefit the United States economy?

The Lend-Lease Act gave the president power to sell, transfer, lend, or lease supplies to nations whose defense was vital to U.S. interests. ... Under the program, the United States provided economic and military aid by lending food, tanks, airplanes, weapons, and raw materials to Allied countries.