Why Vivek Ramaswamy got the most 'boos' at the Republican debate as he went after Haley, Christie

On the fourth Republican debate stage, with just weeks to go before the Jan. 15 Iowa's caucuses begin the 2024 primary, Vivek Ramaswamy's night kicked off with a question about whether he can unify the country despite having a bit of a self-professed "know-it-all" demeanor.

"I think there's a time and place for everything," he told moderator Megyn Kelly, who had noted his penchant for personal insults. "We need somebody in the White House who absolutely is going to be a fighter when it counts."

And for the entrepreneur-turned presidential hopeful, Wednesday night's debate was the time and place for doubling down on his fiery criticism of his opponents -- though he received multiple boos from the audience and and a sharp reprimand from rival Chris Christie as a result.

During one back and forth with the former New Jersey governor, Ramswamy said that Christie was "spewing nonsense."

Christie replied, "This is the fourth debate that you would be voted, in the first 20 minutes, as the most obnoxious blowhard in America. So shut up for a little while."

In total, Ramaswamy was booed at least four times on the stage, underlining his relatively divisive role in the field. He has built a national profile through his presidential campaign but his polling numbers peaked months ago, according to 538's average -- right around the first primary debate, in late August.

Since then, Ramaswamy's support with the GOP base has continued to soften. By the third debate, a 538/Washington Post/Ipsos poll of likely primary voters found he was rated as giving the worst performance on stage.

His first "boos" of the night at the fourth debate came after he described former South Carolina Gov. Nikki Haley -- with whom he has feuded multiple times -- as "the only person more fascist" than the Biden administration. He claimed she believes the government should identify everyone with an identification, referring to her since walked-back comment in November that "every person on social media needs to be verified."

At the debate, Haley defended herself: "We need social media companies to go and fight back on all of these bots that are happening."

Ramaswamy was booed again after insisting she can't name three provinces in eastern Ukraine even as she supports assisting the country in its war against Russian invaders.

"Look at the blank expression," Ramaswamy continued to gibe as Haley stood silent, before he was cut off by Christie, who shouted from across the debate stage -- "enough." Christie went on to slam Ramaswamy for, he said, insulting Haley's intelligence.

Ramaswamy was booed for the third time when he told Christie to leave the stage, and the presidential race, altogether.

The two had a heated exchange after Christie attacked Ramaswamy in defense of Haley,

"If you want to disagree on issues, that's fine, 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 ever started to vote in a Republican primary," Christie said.

"This is a smart, accomplished woman -- you should stop insulting her," Christie continued, prompting Ramaswamy to shoot back: "Chris, your version of foreign policy experience was closing a bridge from New Jersey to New York. So do everybody a favor, just walk yourself off that stage, enjoy a nice meal and get the hell out of this race."

Ramaswamy faced his fourth and loudest boos after holding up a handwritten sign equating Haley with corruption as he questioned her "authenticity" -- a stunt that summed up his opinion of the former U.S. ambassador to the U.N.

"Nikki, I don't have a woman problem; you have a corruption problem," Ramaswamy said.

At the second debate, Haley had admonished him: "Every time I hear you, I feel a little bit dumber." In the days following the third debate, she said that he "may have a girl problem."

Speaking with ABC News Live anchor Linsey Davis after the fourth debate, Ramaswamy doubled down on his attacks against Haley, again claiming she can't name regions of Ukraine -- though she ultimately did on the stage -- calling it an "intellectual fraud."

Asked by reporters in the spin room if she felt that Ramaswamy calling Haley corrupt and fascist was justified, campaign spokesperson Tricia McLaughlin said "it's absolutely justified" after saying Haley's "been pretty hard on him."

Christie was the only other presidential hopeful booed on Wednesday night, when he told the audience during his closing remarks that Trump will be convicted of felonies before Election Day. Trump has denied wrongdoing and pleaded not guilty in his four criminal cases.

"Here is the bottom line -- you can boo about it all you like and continue to deny reality," Christie retorted. "But if we deny reality as a party, we'll have four more years with Joe Biden."