Before The Cold War!!
Before the Cold War America was at peace with the Soviet Union they actually fought together as allies against the Axis powers. So technically America wasn't at peace because of World War 2; to be exact they had like 2 years for them to re-cover and just to get their lives together after World War 2. If you look at it that's not enough time to re-cover from a 6 year war.
Why Did The Cold War Start??
The cold war started because this battle pitted the world's two greatest power between, the capitalist United States and the communist Soviet Union–against each other. These two countries wanted to see who was more improve with technology, its military firepower and–by extension–its political-economic system.