I might go a bit further and claim that Russia would have collapsed without the convoys to Murmansk and to their Pacific seaport Vladivostok.
https://en.wikipedia.org/wiki/Pacific_Route
I think my answer is correct, but I'm not sure.
How did the Lend-Lease Act help the Allied war effort?
A: The Lend-Lease enabled the United States to lend or lease more than $40 billion in weapons, vehicles, and other supplies to those involved in the Allied war effort.
2 answers
http://en.wikipedia.org/wiki/Pacific_Route
1 answer