Can the Second G.O.P. Debate Amount to More Than a Race for Second Place?

The second Republican presidential debate without Donald J. Trump is missing the front-runner’s star power, but the performances of his rivals on Wednesday are still expected to be deeply consequential — forecasting whether the 2024 field of Republicans will consolidate around a single Trump alternative.

For months, Gov. Ron DeSantis of Florida has been the chief challenger to Mr. Trump. But the governor’s downward slope in the polls — some surveys in the early states of New Hampshire and South Carolina have shown him dipping to third place, or worse — have provided a potential opening to wrest that title from him for the rest of the field at Wednesday night’s debate at the Ronald Reagan Presidential Library in California.

Among those watching at home will be some of the Republican Party’s biggest donors who have so far held out from backing any of the candidates. Major contributors are planning to watch the second debate carefully, according to people in contact with several of them, in order to see who, if anyone, they might rally behind in the coming months.

All seven candidates at the debate are facing the dual-track challenge of trying to emerge as a singular rival of Mr. Trump without letting the former president entirely run away with the contest before that happens. His criminal indictments — now at 91 counts across four jurisdictions — have not slowed his momentum, with each week bringing new surveys showing Mr. Trump above 50 percent nationally among Republicans, and no rival registering even half that level of support.

Those who have qualified for Wednesday’s debate are: Mr. DeSantis; former Gov. Nikki Haley of South Carolina; Senator Tim Scott of South Carolina; former Vice President Mike Pence; former Gov. Chris Christie of New Jersey; the businessman Vivek Ramaswamy; and Gov. Doug Burgum of North Dakota. Mr. Trump is skipping the debate to travel to Michigan for an event with union workers.

The most immediate stakes of the debate are likely financial. The last, major public fund-raising deadline before voting in the primary begins is at the end of September. Few events can generate waves of small donations — or help fence-sitting multimillionaires pick a candidate — quite like a powerful showing on the debate stage.

After landing some lines at the first debate, Ms. Haley boasted of raising more than $1 million in the next 72 hours. Mr. DeSantis raised $1 million in 24 hours, his campaign said. And Mr. Scott, who struggled for airtime, was among those not to say anything about his post-debate haul.

For Mr. DeSantis, a superlative showing could quiet the chorus of critics who worry he doesn’t have what it takes to stop Mr. Trump, despite a $130 million super PAC and his standing as the next-most-popular Republican candidate. For others, like Ms. Haley, whom some of the party’s most influential donors are said to be taking a fresh look at after the first debate, it is a chance to try to supplant Mr. DeSantis’s persistent second-place standing.

“You need the field to narrow, so this debate and every debate is important because people are getting to see the options they have,” said Jay Zeidman, a DeSantis donor and fund-raiser in Texas who hosted a recent event for the governor.

Mr. Zeidman’s father, Fred, a veteran fund-raiser in several presidential races, has been an early backer of Ms. Haley, underscoring the divide among donors who would like to see an alternative to Mr. Trump as the nominee.

“Nobody really paid attention to her or knew who she was until the first debate,” said the elder Mr. Zeidman, a fixture in G.O.P. fund-raising circles who was appointed by President George W. Bush as chairman of the U.S. Holocaust Museum.

“I was with her in New York at a fund-raiser last week and it was a room packed with major New York donors who were really hearing her for the first time,” he added. “This is a pivotal week.”

Still, there are questions about how much money will even matter in a race that Mr. Trump leads by so large a margin that many G.O.P. donors have grown fatalistic about the final result.

Campaigning in South Carolina on Monday, Mr. Trump said his opponents “ought to stop wasting their time.” He added: “They’re wasting a lot of time with these ridiculous debates that nobody’s watching.”

Another key factor in shaping the size of the field will be the Republican National Committee’s debate criteria. Candidates must hit a 3 percent polling threshold to be on the stage in California and have amassed 50,000 donors. One candidate at the last debate, former Gov. Asa Hutchinson of Arkansas, failed to qualify on Wednesday.

The debate thresholds will rise to 4 percent in polling and 70,000 donors for a Nov. 8 debate in Miami.

Ms. Haley has ticked up in the polls in both Iowa and New Hampshire in recent weeks but that rise could be as much about a television advertising blitz from her super PAC as her showing in the first debate. In the last two months, her super PAC was the biggest advertiser in both states, spending $6.5 million in Iowa and close to $5 million in New Hampshire — more than her closest competitors, according to data from AdImpact, a media-tracking firm.

She capitalized on the perception of a rising candidate as she went on a fund-raising spree through New York, Florida and Texas, where she has made inroads with some of the same donors who backed Mr. Bush and his father, according to people who have attended her events and are familiar with her fund-raising. She has support from the state’s prosperous Indian American community and from major figures in the energy sector. Texans supporting her include members of the oil-rich Hunt family, the textiles magnate Arun Agarwal and the real estate developer Harlan Crow, who was revealed recently as a longtime benefactor of Justice Clarence Thomas.

Such busy fund-raising trips, however, illustrate an unseen advantage that Mr. Trump holds: He raises all his money online — which requires virtually nothing from the candidate himself — while the rest of the field is making mad dashes across the nation to attend fund-raisers.

Mr. Pence, according to an adviser, spent 15 days in September raising money — more than half the month. And Mr. DeSantis, who had multiple events across Texas last week, is following up the debate with a trip to Northern California to raise more money ahead of the crucial Sept. 30 deadline.

Still, even if Ms. Haley delivers another donor-approved performance on Wednesday night, there’s little chance the field will narrow as much as Republican donors and leaders are hoping. And this is good news for Mr. Trump, who benefits from a large field dividing up the non-Trump vote.

Campaigns have been lobbying aggressively for favorable rules in future debates both publicly and behind the scenes. Mr. Scott, for instance, has argued that stage placement should be determined by a candidate’s standing in early state polling, not national surveys. The DeSantis team has pressed for even higher polling thresholds — even 8 percent — to further narrow the stage as the primaries near.

Debate rules can make a big impact in how television audiences perceive the candidates. In Milwaukee at the first debate, Mr. Christie faced audible boos in the audience after he was critical of Mr. Trump. But the crowd will be much different, and much smaller, in California. A person familiar with the event planning said around 700 people would attend on Wednesday.

Mr. Christie has signaled to several people that he plans to make Mr. Trump more central to his argument at this debate. At the last one, he spent more time trading barbs with Mr. Ramaswamy when the moderators generally avoided mentioning Mr. Trump’s name, calling him “the elephant not in the room.”

Mr. Scott, who had an underwhelming first debate and is polling in the single digits in both national and early state polls, is still raising plenty of campaign cash, including from a New York fund-raising event last week hosted by the billionaire Stanley Druckenmiller. Mr. Scott will be saturating the airwaves over the fall — his super PAC has already reserved $40 million in advertising, the most of any candidate in the primary.

Mr. Scott’s team has signaled he will take a more aggressive approach in the second debate. In the first debate, Mr. Scott declined to take shots at his competitors. Since then, he has called out Mr. Trump, Ms. Haley and Mr. DeSantis over their positions on abortion and has said that Mr. Ramaswamy has taken the “wrong” positions on U.S. foreign policy toward Israel and Taiwan.

But a more confrontational posture would be out of character for Mr. Scott, who told the radio host Hugh Hewitt to expect the “same optimistic, positive approach to debating” in an interview last week. “If we’re going to have a food fight, someone has to bring us back to the issues that are germane to the American people,” Mr. Scott said.

Anjali Huynh contributed reporting.