The USA didn't even need to get involved in the war..the Russians still would have won, and likely taken most of Europe. Total killed for the Americans and British combined was about 250,000. Total killed in the Soviet Red Army was 8.5 MILLION. Over 30 Million served in the Red Army during the second world war. The Russians shot or imprisioned more of their own people for "cowardice", desertion etc that the combined British and American losses. By 1945, as they were entering Germany and laying waste to the country in horrific revenge there was no way that the Germans could have kept up the manpower drain. The Russians were mass producing tanks, artillery guns, small arms, airplanes on their own by then. They were a juggernaut, a titanic force compared to the American and British armed forces at the time. Some of the greatest battles, in fact, almost all of the greatest battles of the war, with the most horrific losses of lives and massive numbers of soldiers and equipment were fought on the Eastern Front.
The reason we in the west usually think so much less of the East front is because we are indoctrinated by hollywood and our history books, taught to think that the British, Commonwealth, American armies were the be all and end all and the war was mainly fought for Western Europe/France. How many have heard of Operation Bagration for example. That was the Soviet surprise attack to push the Germans out of Belorussia in June 1944. It was overshadowed by the D-Day at the same time and we never learn in our history that it was a bigger operation, required much more planning and manpower and was a by far larger and much more momentous outcome than D-Day.
So no, the USA was not the biggest and baddest back then, by 1945, the Soviet Red Army was.
