Winner
Diverse in Unity
By 1945 and until 1948 famine was a reality all over Eurasia. Even the UK, which was barely touched by war, went into rationing, and things got especially bad in 1945-48. Rationing didn't end there until 1953.
The reality, which you refuse to see, was that the UK was even more exhausted that the USSR by 1945. You think they'd have left India go if they weren't? Or lost their grip on the Middle East? France was KO also until the 1950s, and so was occupied Germany. The USA did had more resources and manpower, but it was also politically impossible that they'd mobilize those.
In 1945, it was perfectly possible since the US army wasn't demobilized yet. Only after that had sending troops overseas become a problem. The situation of the UK and France is pretty irrelevant, since most of the fighting would have to be done by the US anyway and they could keep Britain afloat indefinitely.
You also keep discounting the fact that fighting a war overseas is more difficult, both militarily and politically. Hell, they failed to win the Korean War in 1950-53 - which had political support - and you're raving about how they, by themselves, would win a Third World War 3 in 1945?!
Calm down, buddy

Korean war was entirely different type of conflict than this hypothetical war with the Soviets. Moreover, it was fought in the Cold War environment, which simply dictated how far both sides could go, due to emerging nuclear capabilities of the USSR. It was a limited war, not an all out struggle.
In 1945, US was fully mobilized for war. After it demobilized and switched back to peacetime economy and mentality, it was indeed difficult to think about conventional war with the Soviets, but this is not what this scenario is about.