When a politician finally goes down, the loyalists extricate themselves and write their memoirs. 

Lis Smith, who worked for Spitzer and Cuomo, is doing that in a high-profile way with her book. Anything you needed to know about her can be summed up in this excerpt.

Political strategist Lis Smith casts Bill de Blasio as a “gross unshowered guy” who had good reason to be “pissed” about her romantic fling with Eliot Spitzer — exposed by The Post — especially after he failed to woo an endorsement from the ex-governor while running for mayor in 2013.

“Both of us had tried to get in bed with Eliot, but only one of us had been successful,” Smith writes in in her new book “Any Given Tuesday,” an excerpt of which was shared with New York Magazine.

So there’s no particular reason to take Smith’s supposed agonizing about playing defense for former Gov. Cuomo, but it does contain an interesting nugget.

Even after the fateful call when we’d told him that his career was “over,” he tried to press on. He called each of us individually to ask our opinions, seeking a sympathetic ear or some way out of the situation he found himself in. He didn’t find one. The sole exception was former President Bill Clinton, who told him that he needed to go out and address the people of New York directly: to state that his fate was in their hands, not the politicians’. The consensus — among advisers, at least — was that unless Clinton, with his legendary political skills, was willing to do the mea culpa himself, it would do more harm than good.

That is very… Clintonesque indeed.

It’s striking how much Bill Clinton has vanished, a former president who signs his names to bad novels and appears on late late night shows to discuss UFOs. Bill has been overshadowed by Obama, by Hillary and by history. He belongs to another era, a time with very different worries, concerns, and culture.

And yet he’s still around.

Count on Bill Clinton, a guy who has been accused of sexual assault, to be the last man standing behind Cuomo. While Smith and some of Cuomo’s advisers seemed to mull over having Bill do it, considering his famous finger-wagging performance, that doesn’t seem like it would have helped.

Cuomo’s strategy of staying on seems to have been adapted from Virginia’s Gov. Northam and was pegged to a black female constituency. It worked for Northam and partially worked for Cuomo, but the man who originated the strategy was Bill Clinton.