Nothing more or less. Churchill knew that all along, he realized that it was a pact with the devil, and he held his nose closing the deal. Roosevelt was more naïve and we have paid ever since. I am not bashing Roosevelt as I see him as the most successful President that we have ever known, but he did not read Stalin very well.
That said, no matter how rotten Russia is today, you can not ignore their peoples sacrifices in WWII. The fact is that if WWII was a movie, the credits would be something like this: Starring the USSR and Germany. Also appearing, in order of appearance, Poland, England, France, the US, Japan, and a cast of hundreds of millions.
Hitler sealed his defeat when he launched Barbarossa; he had made the fatal military mistake of underestimating his enemy. Hitler sealed the deal by being a horrible warlord; he may have been a fine corporal, but he was a horrible general. The Germans lost over 2,000,000 men killed, wounded or captured on the Eastern Front. Had those armies been available for defending Fortress Europa all of Europe would be speaking German today.
The Soviets lost somewhere in the range of 27,000,000 people during the war. (military and civilian, killed, wounded, captured, missing and deaths by hunger and disease) Those numbers fueled their post war paranoia; is it any wonder? In comparison, total American causalities, Killed, wounded, MIA and captured were just over 1,000,000 in both Europe and the Pacific. (about a third in the Pacific theater)
American industry and agriculture and shipping certainly helped the Soviet Union, but it was not a critical element to their final victory. It surely shortened the war, but it was not decisive. Germany, much like the American South in the Civil War, just did not have the resources to compete with the Russians, and just like the Confederacy, they did not realize it at the start.
I know that someone will want to misconstrue this post as being pro Russian. I assure you, I am not pro Russian, but I am pro history.