Donald Trump emerged the victor from his debate Sunday night with Hillary Clinton, which means he slightly exceeded expectations by not spontaneously combusting on stage, which means his ardent loyalists have again absolved him of sin. “Congrats to my running mate @realDonaldTrump on a big debate win!” tweeted Mike Pence as soon as it ended. “Proud to stand with you as we #MAGA.”

That’s “Make America Great Again,” though at this stage in the campaign it could equally mean “Mount Another Genital Assault.”

The Indiana governor is supposed to be the sober side of Trump-Pence, the guy who keeps cool, knows his policy brief and imposes ideological discipline on a ticket that would otherwise blow whichever way Mr. Trump puffs. But that misreads Mr. Pence’s role in this disastrous GOP season. Mr. Pence isn’t his boss’s junior political partner. He’s his moral enabler.

I use “enabler” in the psychiatric sense, meaning, as Merriam-Webster has it, “one who enables another to persist in self-destructive behavior (as substance abuse) by providing excuses or by making it possible to avoid the consequences of such behavior.” The enabler gets the kids to school when you’re passed out drunk, mops up the mess in the bathroom, pays the bills, and makes things seem OK when they aren’t. Enablers like to think of themselves as altruists or heroes. In truth they’re accomplices.

Mr. Trump doesn’t have substance-abuse issues: His problem is the emission, not ingestion, of poison. As we learned from Friday’s disclosure of his 2005 exchange with Billy Bush, it gushes out of him at nearly every turn, not least in the patter of casual conversation. In the most hideous of Mr. Trump’s now-infamous sentences, it’s hard to decide which part is most repellent: the predatory verb “grab,” the dehumanized object “them,” or the pornographic prepositional phrase “by the p—.”