I offered to help prep Chris Christie for the debate with Donald Trump.

Christie helped prep Trump in 2016, saying he played Hillary Clinton very aggressively so that Trump would think the real thing was “a cakewalk.”

And now, sitting at a table in the Times cafeteria with the former New Jersey governor, I figured I could play Trump.

We have both known the blackguard for decades. And let’s be honest. We want Christie on that wall. After years of watching Republicans cower before Trump, it’s bracing to see the disgraced former president finally meet his mean match.

Even my Republican sister, who does not want to vote for Trump — but may if it’s Trump versus President Biden — sent Christie money to help him secure a spot on the debate stage.

Trump has boasted that he’s so far ahead of his Republican rivals that he might not bother to show up for the first debate in August, hosted by Fox News in Milwaukee.

“I think that he’ll show up at the debates because his ego won’t permit him not to,” Christie said. “He can’t have a big TV show that he’s not on.” He smiled, adding: “He’s on Truth Social going bonkers, and no one’s paying attention? He won’t deal well with that.”

I warned that Trump is an asymmetrical fighter, so it’s hard to know how to go at him. Clinton tried to rise above him, and Marco Rubio imitated his crude style.

“You just brought up two of the most unskilled politicians I’ve ever met,” Christie said, noting about Trump: “I don’t think he’s ever gone up against somebody who knows how to do what he does. He’s never run against somebody from New Jersey who understands what the New York thing is and what he’s all about. For people like me, who’ve grown up here and lived my whole life in this atmosphere, he’s just one of a lot of people I know who have that personality. He knows I know what his game is.”

He said he isn’t running to get back at Trump for giving him a horrible case of Covid. Trump came to debate prep in September 2020 without telling Christie or anyone else that he had tested positive the day before, and Christie ended up in the I.C.U. for seven days. And he said he isn’t seeking payback because Trump didn’t make him attorney general. (Jared Kushner was still nursing a grudge because Christie put Kushner’s father in prison.)

But even for a guy who could be plenty nasty as governor, trying to overturn democracy was a bridge too far.

“The idea that somehow everyone’s going to stand around and wait for him to collapse of his own weight and then say, ‘Oh, I didn’t say anything bad about him,’” he said. “He’s never fallen of his own weight. The only time Donald Trump’s ever backed off in his life is when he’s been beaten to back off. I saw it happen in Atlantic City. He was bankrupt three times. He had to finally give in and close down.”

Christie mocked Ron DeSantis responding to Jan. 6 by saying he was not in Washington — “Was he alive?” Christie asked Kaitlan Collins on CNN. He thinks DeSantis has already lost the authenticity contest: “If you say to Tucker Carlson that Ukraine is a territorial dispute and then a few days later you go to Piers Morgan and you call Putin a war criminal, well, it’s one or the other.”

What about the end of the love affair with Fox News and Trump?

“I’ve known Rupert for a long time,” Christie said. “I suspect Rupert’s view is, ‘Enough is enough.’”

Is Trump, as his former chief of staff John Kelly said, scared to death?

“He’s scared,” Christie said. “Look, a guy like him, the last place you ever want to be in life is in jail because you give up all control, and he’s a complete control freak.” Trump is playing checkers, not chess, Christie said, just scrambling to make that next jump.

Christie is the ultimate Jersey guy. (His relationship with his idol, Bruce Springsteen, which shattered over his stint as a Trump sycophant, is “a work in progress,” he said.) So I wonder how he feels about Jack Smith zeroing in on vivid scenes at the golf club at Bedminster, N.J., with Trump waving around classified documents and then telling reporters it was simply “bravado” and the documents were merely plans for a golf course.

“Yes, because look, for Donald Trump, it is better to be called a liar than to go to jail,” Christie said. “If what it buys him is a get-out-of-jail-free card, he’ll take that trade every day.”

Trump has been peppering Christie with insults about his weight — “slob,” “Sloppy Chris Christie” and a phony video showing Christie feasting at a fried food buffet.

“I’m not going to say it never bothers me,” Christie said, noting that, whenever you’re hit for “a weakness or a failure,” it depends on your mood how hard you take it. But, he added, Trump is no Adonis, so “coming from him? Who cares? Look in the mirror. I always thought it was very funny that he has this vision of himself. He told me one time the reason he ties his ties so long is that it slenderizes him and I should do the same thing.”

Trump is also the one, back in 2005, who first suggested to Christie that he get lap-band surgery, which he eventually did. So, I ask, Trump used to be concerned about your health and now he viciously insults you about your weight?

“That’s, in part, the magic of him,” Christie said. “He’s got it in him to do either. It’s not like he’s unable to be charming. He can be. But only when he’s looking for something from you.”

What about the Biden age debate?

“I think he’s beyond his sell-by date, and I think Trump is, too, by the way,” Christie, 60, said, adding about Biden, “I think his family should let him go home.” He asked, “Are they actually motivated by love for this guy, or is it motivated by the grift?”

And Hunter Biden’s appearance at the state dinner for the Indian prime minister, two days after his plea deal?

“Look, that also shows you Joe Biden’s not in control, because if he were of right mind, I don’t care how much you love your kid, he doesn’t have to be at the state dinner,” Christie said. “It’s not like you’re saying, ‘You can’t come to the White House. I can’t see you. I can’t visit with you. You’re toxic.’”

He believes Kamala Harris is “a problem for Biden, and it will hurt him,” saying, “I don’t think Dan Quayle hurt George Bush 41. But George Bush 41 wasn’t 82 years old.”

Since we’re heading into the Fourth of July, I wonder if Christie is having any acid flashbacks to the Fourth of July weekend of 2017 when, as governor, he was photographed sunning himself on a closed public beach during a state government shutdown.

“My mistake,” he said. “I blew it. But no acid flashbacks.”