When Melania Trump stood by her man-child the other night on CNN over the lewd comments to Billy Bush on a hot mic, she told Anderson Cooper that her husband “was led on — like, egged on — from the host to say dirty and bad stuff.’’

She was offering her best defense. But it was actually the best damnation.

At the final debate tonight in Las Vegas, Donald Trump once more showed how easily egged on he is.

Continuing to deploy lethal darts from her team of shrinks, Hillary Clinton baited Trump into a series of damaging nails-in-the-coffin statements. And it was so easy. The one-time litigator prosecuted the case against Trump, sparking another temperamental spiral, as effectively as Chris Christie once broke down Marco Rubio.

In Trump’s warped fun-house mirror of a psyche, every rejection is a small death. That is why he harps on humiliation, that America is being humiliated on the world stage, that we are losing potency — a theme that resonates with angry voters who feel humiliated by their dwindling economic fortunes and angry about illegal immigrants and refugees swarming in who might be competition.

She once more proved adept at getting her rival’s goat: She again contended that he’s not a self-made man but a spoiled rich kid who was underwritten by his father and she accused him of choking on bringing up the issue of who would pay for the wall when he met with the president of Mexico.

Trump tried to stay calm, but he can never let go of a slight.

He defended himself on groping charges by saying, “Nobody has more respect for women than I do.’’ But he ended up, after Clinton’s hazing — “Donald thinks belittling women makes him bigger” — blurting out as she talked about entitlements: “Such a nasty woman.’’

No doubt it is hard for a man — whose lovely, sphinx-like wife rarely talks at dinners with friends to make room for more talking by Trump — to listen to an opinionated woman speak dismissively to him over 90 minutes.

When Clinton called Trump a Putin puppet, he unraveled, once more proving how malleable he is with anyone from Vladimir Putin to Clinton, who either praises him or pokes him.

“No puppet. No puppet. You’re the puppet,’’ he said, going into what the former Obama chief speechwriter Jon Favreau tweeted was “a full Baldwin.’’ Talking about Putin, Trump once more offered the simple reason he has flipped his party’s wary stance toward the Evil Empire, subjugating his party’s ideology to his own ego: “He said nice things about me.’’ Similarly, he reduced a debate about the Supreme Court to the fact that Ruth Bader Ginsburg had attacked him and had to apologize.

He was so unnerved, he said one of the most shocking things ever heard in a debate, putting his ego ahead of American democracy. Asked by the admirable debate moderator, Fox News’ Chris Wallace, if he would accept the results of the election or reject it as rigged, Trump replied coyly and self-destructively: “I will tell you at the time,’’ adding, “I will keep you in suspense.”

The inanity continued, naturally, when Trump spinners talked to the press after the debate.

As The Washington Post’s Robert Costa tweeted, Sarah Palin told reporters that Trump will accept only a “legitimate” election, and anything else would betray those who “died” for freedom.

And the Post’s Phil Rucker tweeted that “Giuliani just predicted Dems will ‘steal’ the election in Pennsylvania by busing in people from out of state to pose as dead people to cast ballots.’’

Trump tried to give what one of his biographers, Timothy O’Brien, calls his “Clint Eastwood ‘High Plains Drifter’ glare’’ and spaghetti Western talk. “We have some bad hombres here and we’re gonna get ’em out,’’ he said about illegal immigrants who commit crimes.

But he was all hat, no cattle. He gets so easily distracted by belittling statements — even though he dishes them out so easily — that he could not focus to make points in areas where Hillary is vulnerable.

In order to stop losing, he would have to stop losing it.

But he didn’t. He got egged on. Bigly.