Why did the united states decide to broaden its overseas commitments? did the soviet threat justify this expansion of america'scommitments?

Since you mentioned the soviet union I'm going to assume it was the time frame where the U. S. became involved in places like Asia to stop the spread of communism. The soviet threat was its power to turn countries communist and this being horrible is more of an opinion. Americans were and are vehemently against communism which in itself suppresses the people but at the same time getting involved abroad caused the Vietnam war which killed countless Americans.