The US and USSR competed in the cold war, clashing over political and economic ideology. The US was a democratic, capitalist nation, while the USSR was a communist nation. The US was willing to do whatever it took to prevent the spread of communism, including fighting in wars in other countries (Vietnam War). Once nuclear weapons were developed, the constant threat of nuclear warfare was constant between the two nations, although dropping bombs on each other could wipe out most of the world.
