Question

Why was there good reason to fear a war between the United States and the Soviet Union?

Answer 1

The United States being so afraid of communism and its beliefs would be part of it. Another part would be the strength of the USSR, or even, how many people struggled to defeat it.

Answer 2

Both sides owned nuclear weapons, and if there was a war, both sides would use whatever weapons they have, which would include the nuclear weapons. As seen in Nagasaki and Hiroshima, the nuclear weapons were devastating, and if there were to have a nuclear war, the whole world would become ruins and have radiation.

hope this helps