While Nikki Haley has, until recently, run a fairly positive campaign, she has endured relentless criticism from Donald J. Trump and others in his orbit. Her 22-year-old son, Nalin Haley, is not so inclined to pull his punches.
Mr. Haley, who has become a more familiar presence on the trail with his mother, introduced her at events over the weekend, taking some pointed jabs at her onetime Republican rivals.
He has a nickname for Senator Tim Scott: Senator Judas. Another former rival who went full-bore for Mr. Trump, Vivek Ramaswamy, draws Mr. Haley’s comparisons (derogatory) to Pennywise, the clown from “It.”
Ms. Haley, for her part, has been deferential: At one event she ran through “thank you’s” for the other speakers before jokingly saying, “Nalin, I will deal with you later.”
On Saturday, while introducing his mother in Gilbert, S.C., he acknowledged that he was in “the state that raised me,” and “the state that took a chance on my mom.” The current moment, he said, was “like history repeating itself — it feels like 2004, 2010, where the establishment is up against her,” he said.
Then, he got personal.
“We had a lot of them go up to New Hampshire, and I saw Trump standing side by side, he was next to Senator Judas — excuse me, Senator Scott,” he said to “oohs” from the audience. “Ouch,” someone in the crowd said.
(Ms. Haley appointed Mr. Scott to the Senate in 2012 when she was governor of South Carolina, and Mr. Scott is now a key surrogate in their home state for Mr. Trump.)
While Mr. Scott has not responded to the jab, Nathan Brand, a spokesman for the senator, said, “You’d never hear Ms. Frances or anyone from the Scott family talk like that,” referring to Mr. Scott’s mother, Frances Scott.
In the early months of his mother’s campaign, Mr. Haley was relatively neutral, largely re-sharing posts from or positive commentary about the Haley campaign. On occasion, he joined her on the trail, playing games at the Iowa State Fair and attending debates.
But his tone notably shifted after the third debate, when Mr. Ramaswamy, the tech entrepreneur, who was still in the race at the time, mentioned Ms. Haley’s daughter on the debate stage as a means of criticizing Ms. Haley’s stance on TikTok.
“Vivague Ramaslimey backpedaling more than his receding hairline,” Mr. Haley wrote on X, reposting a comment that called Mr. Ramaswamy’s remarks “despicable.”
Shortly after, Mr. Haley went further: He posted a picture of Mr. Ramaswamy next to an image of Pennywise, alongside the caption, “Someone help me spot the difference I’m having trouble.”
Onstage on Tuesday in Summerville, S.C., he revisited those comments. “My mom had a talk with me, and I was like, you know what? I feel awful, and I would like to take this chance to apologize to Pennywise,” he said. “Because Pennywise is a lot less creepy, a lot less of a clown, and he has a much better hairline than he does.”
A spokeswoman for Mr. Ramaswamy, Tricia McLaughlin, responding to the insults, said, “In most cases of campaign banter, I give credit where credit’s due, but in this case, I hope he can develop his trash-talking arsenal to include something that’s mildly funny.”
Compared to her rivals, not to mention the troll army supporting Mr. Trump, Ms. Haley’s internet operation has been rudimentary. She has been critical of social media platforms — at one point calling for all social media accounts to “be verified, by their name” — and has stuck to traditional outreach: posting images of her events and occasionally videotaping “get out and vote” asks.
But Mr. Haley, a senior at Villanova University, has been game to engage, hitting back at her rivals on social media platforms with memes and quips.
In December, while Ms. Haley often sparred with Gov. Ron DeSantis of Florida, Mr. Haley wrote on X that Mr. DeSantis “wants to be Trump so bad it’s embarrassing.”
And in January, he responded to a lengthy post from Mr. Trump, which declared that anyone who supported Ms. Haley would be “permanently barred from the MAGA camp,” saying, “In that case, he should be ‘barred from MAGA’ cuz he’s been our biggest fund-raiser yet with this post!”
His lighthearted remarks on the stump go beyond insults. In Gilbert, he recalled how Ms. Haley, during her run for governor, used to offer him and his sister a quarter for every hand they shook. “Fourteen years later, I’m back — not because I’m getting paid, because I’m not, but because we have serious problems in this country,” he said.
Ms. Haley has praised her adult children’s presence on the trail with her, telling reporters in Elgin, S.C., that with her husband deployed overseas, “they really are trying to step up where they can, and I’m proud.”
Ms. Haley’s campaign declined to arrange for Mr. Haley to participate in an interview.
But in January, after helping collect Iowa caucus registration cards, he told The New York Times that his mother had always let him and his sister participate in her campaigns as often as they wanted. He said she was aware they were in the public spotlight and wanted them “to have as normal a life as possible.”
“She has always been a mom first,” he said.
Jazmine Ulloa contributed reporting.
