It should no more be necessary to write this article than to prove that there were Jews killed in the World Trade Center on 9/11. And yet the mythology refuses to die. Just last week, two well-educated and well-known writer acquaintances of mine remarked in passing on the "fact" that those who serve in the U.S. military typically have no other career options. America's soldiers, they said, were poor and black.

They don't mean this to denigrate their service—no, they mean it as a critique of American society, which turns its...