What factors led the wartime alliance between the United States and the Soviet Union to disintegrate into the Cold War?
What would be a great short answer?
http://www.history.com/topics/cold-war/cold-war-history
Yes,
The factors that led to the disintegration of the wartime alliance between the United States and the Soviet Union into the Cold War can be attributed to ideological differences, competing geopolitical interests, and mistrust between the two powers.
Suspicion had always troubled the relationship between the Western powers and the Soviets. The Soviets didn't trust the West in anything, especially Stalin, though he gave them reasons that they couldn't trust him, either, when his armies began gobbling up Eastern Europe for the "security" of the USSR. Stalin, Roosevelt, and Churchill had very different ideas on what post-war Europe was to be like.
Is this a good answer?