The Republican National Committee says it will require candidates to pledge to not participate in debates run by the Commission on Presidential Debates. What would replace them, if anything, was unclear.The Republican National Committee is preparing to change its rules to require presidential candidates seeking the party’s nomination to sign a pledge to not participate in any debates sponsored by the Commission on Presidential Debates.Republican committee officials alerted the debate commission to their plans in a letter sent on Thursday, a copy of which was obtained by The New York Times. If the change goes forward, it would be one of the most substantial shifts in how presidential and vice-presidential debates have been conducted since the commission began organizing debates more than 30 years ago.The nonprofit commission, founded by the two parties in 1987 to codify the debates as a permanent part of presidential elections, describes itself as nonpartisan. But Republicans have complained for nearly a decade that its processes favor the Democrats, mirroring increasing rancor from conservatives toward Washington-based institutions.The move by the R.N.C. was an outgrowth of those long-held complaints and came after months of discussions between the commission and party officials. According to the R.N.C.’s letter, the chairman of the party’s temporary presidential debate committee, David Bossie, began discussions last year with the debate commission’s co-chairman, Frank Fahrenkopf, a former Republican official.The Republican Party chairwoman, Ronna McDaniel, had demanded that changes be made to the commission and how the debates were held, writing in a letter to the commission in June that the party and its voters had lost faith in the commission.The change requiring candidates to refuse participation in the commission’s debates is to be voted on at the R.N.C. winter meeting in Salt Lake City in February. If the R.N.C. moves forward with it, it is unclear what that would mean for future debates. But it would change the approach to be similar to what happened before the commission existed, when the two parties or campaigns had to negotiate directly and agree on terms, or no debates would take place.Commission officials have privately complained that R.N.C. leaders have conflated the processes around primary debates with those in the general election, which are the only ones the commission is involved with. They have also complained that the commission historically deals with campaigns and not with party committees. While the eventual nominee could decide to debate, there’s far more energy in the G.O.P. base behind abandoning institutions than there used to be.Circumstances could always change and the R.N.C. could choose not to go ahead with the planned rules change. But Ms. McDaniel has walked far out on a limb with her latest letter, and the commission, which usually negotiates with the nominees’ campaigns, is showing no sign of making the R.N.C. a negotiating partner.“The C.P.D. deals directly with candidates for President and Vice President who qualify for participation,” the commission said in a statement. “The C.P.D.’s plans for 2024 will be based on fairness, neutrality and a firm commitment to help the American public learn about the candidates and the issues.”One major concern for the R.N.C. was the timing of the first debate in the 2024 election cycle.In 2020, more than one million ballots were cast before the first presidential debate on Sept. 29 that year, after some states changed their election rules because of the coronavirus pandemic and expanded both absentee and early voting. The party has been pushing the commission to host a debate before early voting begins in 2024.Former President Donald J. Trump has criticized the commission since his first campaign, against Hillary Clinton in 2016, when he complained that one of its co-chairs, Mike McCurry, was a White House press secretary under President Bill Clinton. He also complained then that the debates were being held at the same time as N.F.L. games. Mr. McCurry later condemned Mr. Trump’s attacks on the media as president.Officials with the commission told the R.N.C. in December that one of the party’s demands in particular was unacceptable: having nonvoting representatives of either the R.N.C. or the Democratic National Committee at the commission’s board meetings. The commission wrote that it was still studying that and other concerns the R.N.C. had raised, including the choice of moderators, as part of its review before the 2024 campaign cycle.“We take the R.N.C.’s observations and suggestions seriously and, as we have said previously, we will give them careful consideration,” the commission’s letter read. “In furtherance of our position as a nonpartisan, neutral body, which neither favors nor disfavors any party or candidate, we do not negotiate the terms or conditions of our operations with anyone.”But in her letter on Thursday, Ms. McDaniel replied that the commission’s response seemed designed to “delay any reform until it is too late to matter for the 2024 election.”She added that the Republican National Committee’s duty was to ensure that its candidates debated their opponents on a level playing field.“So long as the C.P.D. appears intent on stonewalling the meaningful reforms necessary to restore its credibility with the Republican Party as a fair and nonpartisan actor, the R.N.C. will take every step to ensure that future Republican presidential nominees are given that opportunity elsewhere,” Ms. McDaniel wrote.Accordingly, she added, the R.N.C. would start the process of amending its rules at the winter meeting “to prohibit future Republican nominees from participating in C.P.D.-sponsored debates.”It remains to be seen what, if any, new entity the Republican Party will choose as a host for debates and whether Democrats will agree.Republicans have long complained about how the commission handles debates, going back to the 2012 campaign, when Senator Mitt Romney of Utah was the Republican nominee against the incumbent Democrat, President Barack Obama. The moderator of the town hall-style debate, Candy Crowley, then with CNN, fact checked Mr. Romney in real time about a claim he made about Mr. Obama, prompting an outcry from conservatives.But the intensity of frustration with the commission has increased since Mr. Trump first became the Republican nominee in 2016.Mr. Trump’s adviser, Rudolph W. Giuliani, argued with the commission at the second debate with Mrs. Clinton, when he tried to seat women who had accused Bill Clinton of sexual misconduct near the stage. Mr. Trump has also complained about moderators repeatedly, insisting that both the former Fox News anchor Chris Wallace and the NBC News reporter Kristen Welker were biased against him (Mr. Trump said after the debate that Ms. Welker had been fair).Mr. Trump announced three days after the first presidential debate in 2020 that he had been infected with the coronavirus. He had appeared sick to some onlookers at the first debate, and his former White House chief of staff, Mark Meadows, wrote in a book about the presidency that Mr. Trump had in fact had one positive coronavirus test in the days before the debate, followed by a negative one.The commission changed the second presidential debate to a virtual format, prompting Mr. Trump to withdraw from it after a contentious debate with the Democratic nominee, Joe Biden, for which Mr. Trump was heavily criticized.Mr. Trump’s campaign manager at the time, Bill Stepien, wrote a blistering letter to the commission after the second debate format was changed, accusing the commission, among other things, of omitting the topic of foreign policy to try to help Mr. Biden.Mr. Romney, who is Ms. McDaniel’s uncle, said that it would be “nuts” to go ahead with withdrawing from the commission debates. “The American people want to hear from the nominees of the two respective parties,” he told HuffPost. “It’s a good chance to understand their views and to see them in a high-pressure situation. It’s a great service to the public.” More