https://en.wikipedia.org/wiki/Lend-Lease
After a decade of neutrality, Roosevelt knew that the change to Allied support must be gradual, given the support for isolationism in the country. Originally, the American policy was to help the British but not join the war. During early February 1941, a
Gallup poll revealed that 54% of Americans were in favor of giving aid to the British without qualifications of Lend-Lease. A further 15% were in favor of qualifications such as: "If it doesn't get us into war," or "If the British can give us some security for what we give them." Only 22% were unequivocally against the President's proposal. When poll participants were asked their party affiliation, the poll revealed a political divide: 69% of Democrats were unequivocally in favor of Lend-Lease, whereas only 38% of Republicans favored the bill without qualification. At least one poll spokesperson also noted that "approximately twice as many Republicans" gave "qualified answers as ... Democrats."
[18]
Opposition to the Lend-Lease bill was strongest among isolationist Republicans in Congress, who feared the measure would be "the longest single step this nation has yet taken toward direct involvement in the war abroad". When the
House of Representatives finally took a roll call vote on February 8, 1941, the 260 to 165 vote was largely along party lines. Democrats voted 236 to 25 in favor and Republicans 24 in favor and 135 against.
[19]
The vote in the Senate, which occurred on March 8, revealed a similar partisan difference: 49 Democrats (79 percent) voted "aye" with only 13 Democrats (21 percent) voting "nay". In contrast, 17 Republicans (63 percent) voted "nay" while 10 Senate Republicans (37 percent) sided with the Democrats to pass the bill.
[20]
President Roosevelt signed the Lend-Lease bill into law on March 11, 1941. It permitted him to "sell, transfer title to, exchange, lease, lend, or otherwise dispose of, to any such government [whose defense the President deems vital to the defense of the United States] any defense article." In April, this policy was extended to China,
[21] and in October to the Soviet Union, which was
attacked by Germany on 22 June 1941. Roosevelt approved $1 billion in Lend-Lease aid to Britain at the end of October 1941.