Why did Congress pass the Lend-Lease Act in 1941?

Basic Info: Passed on March 11, 1941, this act set up a system that would allow the United States to lend or lease war supplies to any nation deemed "vital to the defense of the United States."

Why: Proposed in late 1940 and passed in March 1941, the Lend-Lease Act was the principal means for providing U. S. military aid to foreign nations during World War II