We know Mr. Trump’s early transgressions by heart: the female reporter who had “blood coming out of her whatever”; the mocking of a physically impaired reporter; the maligning of a judge because of his Mexican parents; the insulting dismissal of the grieving, Gold Star-parent Khans; the promised mass deportation of eleven million—or two million—undocumented immigrants, and more. Each of these remains a disqualifier for a candidate who will represent every one of us, should he win, but we now are almost willing to turn them into colorful little impairments. “Oh, that’s ol’ Donald—that’s the way he is.”

But I stick at a different moment—the lighthearted comment he made when, in early August, an admiring veteran presented him with a replica of his Purple Heart and Mr. Trump said, “I always wanted to get the Purple Heart. This was much easier.” What? Mr. Trump is saying he wishes that he had joined the armed forces somehow (he had a chance but skimmed out, like so many others of his time) and then had died or been scarred or maimed in combat? This is the dream of a nine-year-old boy, and it impugns the five hundred thousand young Americans who have died in combat in my lifetime, and the many hundreds of thousands more whose lives were altered or shattered by their wounds of war.

I take this personally, representing as I do the last sliver of the sixteen million Americans who served in the military in my war. I had an easy time of it, and was never in combat, but, even so, as I have written, I experienced the loss of more than twenty close friends, classmates, and companions of my youth, who remain young and fresh in memory.