I mean, it's not 100% true but the actions of Russia during WW2 make this pretty true, and the fact that it seems the US intentionally stayed out of the way to inflict as much damage on Soviet Russia as it could before we got involved. There is no situation where you look at the number of deaths in the war and judge their massive suffering of the Soviet people as anything other than key in the defeat of Nazi Germany.

I'm not about to say that the non aggression pact wasn't a problem, but WW2 finds lots of organizations in the same boat that we can attack in the same way. It was an old system where bodies and land meant power, a system that is really dying.

The Americans chose a master of logistics (Eisenhower) as the supreme commander in Europe, and indeed delayed invasion by a year to minimize casualties and retain control of territory once conquered. That it caused more privation for the Russians was considered a convenient side effect, not a primary aspect.

The US was hardly hurt by the war at all, suffering comparatively few casualties; as their states were never actually attacked their primary contribution in Europe was to ship material from their factories to Russia and the other allies. Factories which after the war switched back to making commercial goods.

The war in the Pacific was a different matter, but again, only some US colonies were attacked and civilian suffering even in those territories was nothing compared to what other countries had to deal with.

I'm not a history expert at all but I think this is a massive over simplification, that ignore context of the time. My understanding is that the US was woefully unprepared (particularly the Army) for WW2 due to its non interventionist stance in the years prior, and had to be reconstituted first. Moreover the U-boats were sinking large numbers of ships in the Atlantic that had to be dealt with.