Why was the u. s involved with the cold war

Because both countries had the atomic bomb it was impossible for them to go to war against each other.

They were engaged in a Cold War between 1945 and 1989 – a war without actual fighting between American and Russian soldiers. Since, they can't actually go to war against each other because both countries have the atomic bombs.

Accumulating more land so that your country can continue expanding without running into problems such as overpopulation