Ive been in a few arguments between friends over US involvement in the war, and it's a common circlejerk that the US didn't do much at all in scale to the Soviets or even the British, and i'd like to know historian's viewpoints on the matter.
When asked this question, my response is generally that the US industrial complex won the war for the allies. The statement that the US did do as much as the Soviets or the British is true in some contexts and false in others.
We lost far fewer soldiers than the Soviets, however we supplied just as many considering the population of the US was significantly smaller than that of the USSR. Prior to our direct involvement against the Soviets, we supplied them with a substantial amount of resources necessary for waging their war against Germany. Trains and trucks, tanks, money, food and basic resources were among the many things that the US supplied. Without our support, it is likely that Hitler's army would have claimed a significant more land and that the Soviet army would have been unable to defend against further invasion.
The same goes for the allied powers. The US provided resources for the western front as well.
Once we became involved after Pearl Harbor, we eventually mobilized over 12 million men for the war efforts. We carried out attacks simultaneously in the Pacific/Japan and German. We had troops on the Pacific islands, Italy, northern Europe and Africa. And this all happened at the same time, we covered a large amount of area in support of the allies. We also had the largest, best and most well-supplied air force in the war. Not to mention the ability to drop nuclear bombs, something no one else could do at that point.
Back to my original claim about the industrial complex... the Soviets were incapable of producing munitions and equipment quickly--or in the case of planes and ships, at all. Germany destroyed a huge percentage of Soviet tank forces in 1941. The US led the world in steel production and manpower in the mills here quickly adapted to war-time production. The men and women at home stepped up their efforts and greatly assisted our forces around the world. We sent equipment and ammunition to the British for their forces.
Therefore, the argument that US did little is invalid. If it hadn't been for the forces on the ground and in the air, the industrial complex at home and the full support of the American people - the outcome might have been quite different.
Always more than can be said on a topic, but this previous answer will likely help satisfy your curosity.