Why did the US and Soviet Union get involved with the Cold War?
The Soviet Union and the US got involved in the Cold War because they had different economic and political systems. Their systems were completely opposed to one another. Each system taught that the other system was evil. This caused them to be suspicious of one another.
From this initial suspicion, Cold War tensions soon arose. The Soviets feared the Americans would use things like their initial monopoly over the atomic bomb to destroy them. The Americans became more and more opposed to the Soviets as the Soviets did things like blockading Berlin. These sorts of actions confirmed the suspicions that each side had about the other. In this way, the Cold War began.