The United States were very panicked by the spread of communism which was under the guidance of the Soviet Union. In order to stop the process, and not allow further influence and spread of the communism in territories of their interests the United States undertook multiple actions.
Their actions ranged from diplomacy, threats, military offensive, infiltrating people, sponsoring coups, militarizing certain groups.
That led to lot of conflict in Asia and Africa, with the the conflicts always being on the territories of the countries that were in between the United States and the Soviet Union. Both of these countries were sponsoring and directly supporting the military forces of other countries and of course, as always, the most affected were the ordinary people.