Was the US involvement in the Vietnam War conflict justified?

Its a controversial question, some people say its justified because the US was trying to prevent the spread of communism but others say its not because the US failed, and they lost the lives of many soldiers when they weren't really involved in their conflict anyway

Explanation:

united states reinforcements contributed greatly to three allied victories in france at: cantigny (first major american battle), argonne (the largest in the united states military history, involving 1.2 million american soldiers), and château-thierry (one of the first actions under general pershing).