Cut off the lend lease gravy train to the USSR and they would be hurting in short order.
That being said, such an effort would certainly face unforeseen issues and be painful for all involved by the time it was completely finished. The US swept the floor with all others when it came to logistics, but this is still an invasion of Russia we are talking about.
Also the will of the American People to continue the fight would also have to come under serious consideration. I have always wanted to find a source that spoke about what level of dissatisfaction there was among Americans leading up to V-J day (if anyone knows any, please suggest them!)
God only knows what the long term political ramifications would be, but if WWI’s effect on the European psyche is any guide, I can’t imagine they would be positive.
“I have always wanted to find a source that spoke about what level of dissatisfaction there was among Americans leading up to V-J day (if anyone knows any, please suggest them!)”
However, if it would have been a situation where it looked like the Russians tried to “Pearl Harbor” us, I’m thinking that the reaction would have been something like “well, let’s finish off that Stalin bastard, too, and then be done with war.”