It’s rich, as the English would say, that Donald Trump is trying to profit from Anthony Weiner’s latest mortification, because Trump is to his persevering supporters what Weiner was to his long-suffering wife: a scoundrel undeserving of so many second chances; a head case incapable of the redemption that’s supposedly just a few extra measures of discipline away; someone selling himself as a servant of the public although he’s really a slave to his own raging ego and unquenchable needs.

When Trump looks in the mirror, there’s a whole lot of Weiner staring back at him.

The details are tawdrier in Weiner’s case, and the stakes far smaller. But both men are creatures of potent want and pure compulsion who lucked into forgiving audiences. Weiner’s finally stopped forgiving: Huma Abedin announced that she was formally separating from him after six years of marriage.

Trump still has legions by his side. But for how long?

On the home page of The Times’s website on Monday, coincident with the news story about Weiner’s latest sexting and Abedin’s break with him, was a chart documenting when and why 110 G.O.P. leaders gave up on Trump.

The left side of the chart presented a timeline of his apostasies and indecencies, and it alone was transfixing: a reminder that any other candidate at any other time would have been undone by just one or two of these outrages; an illustration of the way they keep coming, no matter how ardently his inner circle pleads with him for calm, no matter how furiously the outside world reacts. He can’t help himself.