Former New Jersey Gov. Chris Christie and businessman Vivek Ramaswamy went after each other Wednesday in one of the most contentious fights yet at one of the Republican presidential debates.

The fight broke out after Ramaswamy mocked former South Carolina Gov. Nikki Haley’s intelligence, saying both she and President Joe Biden couldn’t name “three provinces in eastern Ukraine that they want to send our troops to actually fight for.”

“She has no idea what the hell the names of those provinces are, but she wants to send our sons and daughters in our trimmings and our military equipment to go fight it,” said Ramaswamy, who has criticized Haley’s foreign policy views as too hawkish.

“Look at the blank expression,” he added. “She doesn’t know the names of the provinces.”

Before Haley could respond to Ramaswamy’s missive, Christie took aim at the 38-year-old presidential contender, first blasting him as a flip-flopper who backs away from certain comments he has made previously on the campaign trail.

“This is the fourth debate,” Christie said, “that you will be voted in the first 20 minutes as the most obnoxious blowhard in America.”

“We’re now 25 minutes into this debate, and he has insulted Nikki Haley’s basic intelligence, not her positions, her basic intelligence,” he added.

He pointed not just to Ramaswamy’s comments about Ukraine, but about Ramaswamy’s three-year-old child’s ability to tell the difference between Israel and the U.S. on a map — a difference he suggested Haley could not make.

“Look, if you want to disagree on issues, that’s fine,” Christie said. “And Nikki and I disagree on some issues, but I’ll tell you this. I’ve known her for 12 years, which is longer than he’s even started to vote in the Republican primary.”

“And while we disagree about some issues, and we disagree about who should be president … well, we don’t disagree on this,” he continued. “This is a smart, accomplished woman. You should stop insulting her.”

Christie and Ramaswamy both are long-shots for the nomination — they trail Trump by even more in the early states and nationally than Haley and DeSantis, who trail by more than 20 points across the board. Should Christie drop out of the race and back Haley, though, it could give her a meaningful boost, particularly in New Hampshire, where he enjoys his strongest support.

But the fight between Christie and Ramaswamy did not end there.

Snapping back, Ramaswamy pointed to the “Bridgegate” scandal, saying Christie’s “version of foreign policy experience was closing a bridge from New Jersey to New York.”

Bridgegate was a scandal in New Jersey during Christie’s stint as governor, in which his appointees conspired to create a massive traffic jam in Fort Lee, N.J., by closing lanes on the George Washington Bridge as political payback.

“So do everybody a favor, just walk yourself off that stage, enjoy a nice meal and get the hell out of this race,” Ramaswamy said, adding that Christie and Haley want to send “your sons and daughters to go die in Ukraine.”

“Neither of them could even name for you the provinces that they actually want to protect,” he continued. “And [these are] the people who have been touting their so-called foreign policy experience. It is intellectual fraud.”

He went on, calling Christie and Haley “toxic” neoconservatives, adding that while “you can put lipstick on a Dick Cheney,” name-checking the former vice president, they are “still a fascist neocon.”

Christie responded, saying he was serving as U.S. attorney in New Jersey during the Sept. 11, 2001 terror attacks, dealing with the aftermath of terrorism at the same time Ramaswamy was “sitting with a smart a– mouth at Harvard.”