BlackStar42 said:
Because it would have cost millions of lives and would have failed miserably. One of the laws of war is: you DO NOT invade Russia. Only one man's ever conquered it, and Russia wasn't even a unified state at the time.
The Russian occupation of Eastern Europe also cost millions of lives, but if we'd managed to win a war against the USSR we at least wouldn't have had to endure half of Europe being taken back to the Dark Age thanks to the wonders of Communism. And I am well aware of the do not invade Russia rule, but I would hope that the allies would have learnt from the failings of Napoleon and the Third Reich (although the US also used their land army in Asia, which is also advised against, so maybe my faith is misplaced). Also you wouldn't necessarily need to invade Russia since you may be able to win the war in Eastern Europe.
halfeclipse said:
Russia would have won, resulting in even more (if not all) of mainland Europe, and possibly Japan under the Soviets. The Russian army wasn't the best equipped, but it was HUGE, and it would have been very hard for the US to effectively attack Russia across both an ocean and most of a continent even if their had been a public will for another long, ugly war.
I disagree that Russia would have won - of all the major countries involved in WW2 the US is more or less the only one that isn't in complete ruins by this stage, they are better armed and have a more powerful industrial base. I don't think it would have been easy and may even have ended in some kind of stalemate, but I don't think the Russians would just completely destroyed the entire US army and whats left of the British commonwealth. Also the allies could have just gone round the Caucasus if they really needed to and capture all the Russian oil fields behind them - that would effectively be war over if the Russians couldn't recapture them. I do agree that the people probably wouldn't have stood for another war though, so it would have been difficult to start one.