People are usually surprised to learn that Vietnam was fought mostly by volunteers while WWII was fought mostly by draftees.
Losses were about 70% draftees in WWII and about 70% volunteer in Vietnam.
During the Vietnam war, myself, my younger brother and stepbrother volunteered for Army while my older brother went Navy.
There are a lot of leftist myths about America and war including claims that only the poor and losers serve in the military.
So many men wanted to fight after Pearl Harbor that the military couldn’t process them and industry couldn’t spare them, so the government told men to wait until their draft number came up.