World War 2 ended with the unconditional surrender of both Germany and Japan. There were no negotiations.
There were negotiations
But we were brutal
It will be hard to get an unconditional surrender from Russia, Harder still to get one from the United States. This will be like WW I a war not of mobile armies but a war of attrition. Slow, pounding death grip, How many years can we fight? How many need die? Two million? Five Million? wait till American start to die? Happy New Year!