Pressure on Curtis Sliwa to drop out of the New York City mayor’s race is mounting as the candidates prepare for their first televised debate on Thursday.

The debate could be a make-or-break event for Mr. Sliwa and former New York State governor and Democrat-turned-intendent candidate, Andrew Cuomo, both of whom are trailing the Democratic nominee, Zohran Mamdani, in the polls. This is the first time all three major candidates will share a stage. Early voting starts in nine days.

Sources tell The New York Sun that President Trump called billionaire grocery magnate, John Catsimatidis, as recently as last week to pressure him to get Mr. Sliwa out of the race. Mr. Catsimatidis’ radio station has long employed Mr. Sliwa as a WABC host and Mr. Catsimatidis has deep connections to the state GOP, though he is not backing the Republican in this race.

“I think if he doesn’t break 15 to 17 percent in the next seven days he has to make the tough decision,” Mr. Catsimatidis told the Sun by text. He did not respond to a text about the president, but when asked how he plans to convince Mr. Sliwa to drop out, Mr. Catsimatidis replied, “We don’t want to lose our city to socialist [sic].”

Mr. Sliwa says the only way he’d leave the race is “in a pine box.” Mr. Cuomo got a chance to debate Mr. Mamdani in the primary — when he failed to do adequate opposition research on the 33-year-old Democratic Socialist — and lost the election by 13 points. Cuomo supporters say this debate is a chance at a redo, and potentially a last stand.

For Mr. Sliwa, the debate is a chance to introduce himself to potential voters who haven’t been paying close attention to the race. The Guardian Angels founder defies GOP stereotypes and is quick with funny soundbites from his years as a talk radio host. He says he won’t be donning his signature red beret on stage.

“No pressure. I’ve made it very clear that I am not dropping out under any circumstances,” Mr. Sliwa tells the Sun. On Mr. Catsimatidis, Mr. Sliwa says he didn’t support his last run either, so this isn’t new. “He has never supported me,” he says. “The people will decide who the next Mayor is.”

“Every debate has a chance to move the needle. Very few do,” a political strategist, E. O’Brien Murray, who registered the first pro-Sliwa super PAC last week, tells the Sun.

Mr. Murray says “the average viewer doesn’t watch the debate,” it’s the viral moments and how the debate is reported on that has the potential to shape public opinion. President Biden’s disastrous debate performance in 2024 torpedoed his reelection bid. Governor Rick Perry tanked his presidential campaign by forgetting the three federal agencies he wanted to eliminate. Ronald Reagan saved his campaign with a quip about Walter Mondale’s “youth and inexperience.”

“Curtis has to be authentic, and people can relate to him,” Mr. Murray says. He says Mr. Cuomo’s challenge is that he has trouble connecting with voters and often sounds condescending. “He’s still behind the podium all the time, lecturing to people like they’re in high school,” he says.

Mr. Mamdani is leading in the latest Quinnipiac poll with 46 percent support to Mr. Cuomo’s 33 percent and Mr. Sliwa’s 15 percent. This is the first major poll to be released since Mayor Eric Adams suspended his reelection campaign, and it shows Mr. Cuomo gaining 10 points from one month prior — virtually all of Mr. Adams’ base.

Cuomo supporters say if Mr. Sliwa drops out and his 15 percent support goes to for Mr. Cuomo, the former Empire State governor could win.

That’s a big if. “I don’t think we should assume that,” Democratic strategist, Michael Hardaway, tells the Sun.

“I actually don’t think that tonight’s debate will move the needle much,” Mr. Hardaway says. “I just don’t see Curtis as really having a chance here, and Cuomo has such a significant mountain to climb.”

Strategists say a catastrophic gaffe by Mr. Mamdani is the only potential wild card for the debate. The state assemblyman, though, has proved adept at taking incoming fire. He survived his first Fox News interview unscarred on Wednesday.

For Mr. Sliwa to gain in the polls he will have to show that he can transcend his image as a shock jock vigilante and effectively govern from Day One. He earned 28 percent in the 2021 New York City mayoral race. He is now polling at half that, as many Republican business leaders are backing Mr. Cuomo as the pro-capitalist candidate they think has the greatest shot at winning. Mr. Sliwa calls himself a populist, and he has strong support among the outer borough and working-class GOP base.

“Curtis Sliwa is a great guy that’s done a lot of good things with the Guardian Angels. I don’t know if the Republican Party can get the vote out,” a former New York State Republican Party finance chairman, Arcadio Casillas, tells the Sun. He says the numbers show the only way to beat Mr. Mamdani is by mobilizing substantially higher turnout than previous mayoral elections.

Other strategists who’ve spoken to the Sun say Mr. Cuomo’s negatives — higher than any candidate in the race — are his biggest liability. Many of the voters he will need to come out are not enthusiastic about voting for him, according to polls. Mr. Mamdani’s supporters, meanwhile, are committed to their candidate.

“Mamdani has managed to capture the unaffordability issue in a way that the other two candidates have not,” Mr. Hardaway says. “The problem is too many rich New Yorkers live in a bubble, and they have no idea. They didn’t see this coming.”

“The caked has been baked,” he says.