▶ No.489660
The Kent State massacre was a regular crime. Had it been committed as part of, or under the auspices of, the "war effort," or had it been committed in or anywhere near the battlefield, or had it been committed by occupying soldiers in the place they were occupying, then it would have been a war crime.
Obviously Mai Lai and things like that were war crimes. Mai Lai is crazy - growing up I don't remember hearing as much about how the American soldiers were gang raping women and children during that.