The US had transport by ship tens of thousands of troops, personnel, and equipment all while fighting the Japaneses for thousands o miles just to get to the battlegrounds of the pacific. Simultaneously doing the same thing to invade Northern Africa AND building THOUSANDS of miles of roads through Canada just to get to the fight up in the fight on AMERICAN soil (Aleutian Islands). All this while rebuilding not only your own army, navy, and air force from almost nothing. And while all this is going on we also had to provide tanks, Airplanes, Trucks, Ships, Trains, Weapons, Equipment and millions of tons of supplies to various countries all over the world; INCLUDING the damn commies. All this on a whim with little to no warning that we would be involved in the war.

On the other side. Russia had more then TWO YEARS to create an war machine and the logistics to support it while it helped Hitler wage war against the Baltic States. And when Hitler did turn against Russia, Russia was only fighting on its own soil with VAST amounts of help from The Allies.