The US decided to go into Vietnam in order to stop the spread of communism, which would imply that there was justification for going to war in Vietnam. However, this is not the case. The US took it upon itself to crush communism and spread capitalism but did so in arguably the worst way possible: bringing in heavy weaponry, destroying land, and killing innocents. So, was the US justified in going to WAR? No. Was the US justified in trying to diplomatically intervene? Maybe.
