Was the Vietnam War a true civil war between North and South Vietnam, or was it more than that?

North Vietnam was communist and South Vietnam was non-communist. Communist countries supported North Vietnam while non-communist countries supported South Vietnam.

The war was more than a civil war between this divided country. There were factors involving other nations that started the war. Between 1945 and 1954, Vietnam had waged an anti-colonialism war against France, and in turn the United States gave Vietnam over two and a half billion dollars in support. It was the intention of France to restore its colonial dominion after WWII. In 1954, Vietnam gained its independence from France and consequently was temporarily divided into North Vietnam and South Vietnam. South Vietnam refused to attend unification elections and the United States supported them.

So all of these events led to the conflict.