Without Western intervention, The Nazis would have defeated the Commies. The Nazi state then would have had everything west of the Urals. That would have been a nightmare for generations at the very least.
The time for the US to stay out of European affairs was WWI. There were no Nazis, the Germans were not seeking territorial aggrandizement and were not seeking to take over. They were fighting a defensive war. It was the Russians/French who wanted to upset the apple cart, not the Germans. Had we stayed out of that war, very likely it would have ground to a reasonable negotiated settlement. There would have been no Versailles Treaty and no Hitler (at least politically) and no WWII.
With a Kaiser whose stated goal was to form “a United States of Europe against America”, that was never going to happen.
And remember, Wilson’s re-election slogan was “He Kept Us Out Of War”.
Not much of a difference really. Same cold war but with the Third Reich instead of the USSR. Same same.