McConnell’s Early Decision to Step Aside Fuels G.O.P. Fight to Succeed Him

The decision by Senator Mitch McConnell to step away from leadership at the end of the year has thrown Senate Republicans into an extended, potentially disruptive nine-month battle to succeed him in the middle of a presidential race and a campaign for control of the chamber.

A contest that had been simmering in the background was suddenly thrust front and center this week by Mr. McConnell’s earlier-than-expected announcement that he would not seek to remain his party’s leader. The contenders immediately began wooing their colleagues for the chance to become the first new face of their party in the Senate in almost two decades.

“It is a lot of runway,” Senator John Thune of South Dakota, the No. 2 Republican, said about the months remaining before the party’s first seriously contested leadership race since Mr. McConnell took over in 2007. “But it is what it is. So you just have to adapt.”

Congressional leadership contests are the most inside of inside games on Capitol Hill, with the secret-ballot outcomes determined by personal relationships, grudges and who lawmakers see as the best option for their own ambitions as much as serious policy positions or the state of the institution. The true electorate is not even known yet, since those voting for next year’s leader will include anyone who wins a seat in November — and exclude anyone who loses.

That reality was underscored on Friday morning when Senator John Cornyn of Texas, the former No. 2 Republican, enthusiastically endorsed Kari Lake, the Republican front-runner in Arizona’s Senate race. Mr. Cornyn, the only one so far to officially announce that he is running, has tried to get off to a quick start in his drive to replace Mr. McConnell, with an all-out push to his 48 Senate colleagues and beyond.

“I’ve called them all,” Mr. Cornyn said in an interview. “I’ve called them all and met with a number of them personally. Most of them say, ‘Well, you know, we’d like to have a more extended conversation.’”

While Mr. Cornyn intimated that he had already secured commitments, most Senate Republicans are going to hold back on any pledges, hoping to wring the most out of their leadership vote and squeeze the contenders by playing them off against one another. There is a long way to go.

And the shadow of former President Donald J. Trump looms over the race. The decision by Mr. McConnell, who does not speak to Mr. Trump, to step aside was a tacit acknowledgment that he had fallen too far out of step with the MAGA base of the party that reveres the former president to remain as leader. Mr. Thune has also been harshly critical of Mr. Trump, as has Mr. Cornyn — though both have endorsed him in recent weeks.

It is quite possible that the two Johns — Mr. Thune and Mr. Cornyn — will be joined by a third, Senator John Barrasso of Wyoming, the No. 3 Senate Republican who has indicated a strong interest in rising in leadership and has recently positioned himself to the right of his two most likely opponents. Though he has not declared his intentions, he endorsed and appeared in Arizona with Ms. Lake this week. He has maintained strong ties to Mr. Trump.

Another name being circulated is that of Senator Steve Daines of Montana, the head of the National Republican Senatorial Committee, making him responsible for the party’s effort to capture the Senate. A strong showing in November could make him a viable candidate with a built-in base of support from those he helped secure seats as well as other grateful colleagues. He, too, is close to Mr. Trump.

The far-right reaches of Senate Republicans may also put forward a candidate — or at least try to leverage their bloc of votes to win concessions from the others, as archconservatives in the House did in the leadership struggle across the Rotunda. Some want to see another try by Senator Rick Scott of Florida, whom Mr. McConnell easily dispatched in a leadership election in 2022.

“I ran 14 months ago because I think we have to have change,” Mr. Scott said, though he did not declare his own candidacy. “I think there’s going to be a lot of people.”

The leadership fight promises to be a distraction at a minimum as the contenders jockey for position and could be more if matters get testy — though the candidates say they expect to stay civil, at least publicly.

“I don’t expect any animosity between the members,” Mr. Cornyn said. “I respect my colleagues. I think John Thune will be in the race, and John’s a good senator and a friend of mine.”

Given the time remaining until the election, some senators have suggested that it would be better if Mr. McConnell gave up the leadership reins more quickly and forced the internal contest sooner. But so far that seems unlikely as he appears determined to wait until after the election.

The traditionally conservative Mr. Thune is considered a straight shooter and was seen as doing a capable job when Mr. McConnell was sidelined last year after a fall. Mr. Cornyn, a former head of the Senate campaign organization, is known for his fund-raising prowess. Allies say he has already amassed $13 million for Republican candidates this election cycle.

All the contenders and their colleagues say they are interested in ways to respond to widespread unrest about how the Senate works — or does not work — and better empower individual senators after much of the decision-making has been concentrated for years in the leadership suite of Mr. McConnell, where he reigned supreme.

“It’s a lot of listening,” Mr. Thune said about his meetings with colleagues. “Obviously it’s a new era and a reset. People have a lot of ideas about how to make the place work better and improve the work we do around here.”

“A lot of the anger and the frustration you hear from senators is because they’re basically being treated like potted plants,” Mr. Cornyn said. “They don’t get to participate either in the committee markups or in an open amendment process on the floor. And I’d like to change that.”

Whoever emerges from the leadership battle is in for a tough job in what will almost certainly remain a Senate narrowly split between Democrats and Republicans, with a widening divide between those on the G.O.P.’s far right and those who remain right of center.

“I admire people who want to do it, because it takes time away from your family and is hard,” said Senator Lindsey Graham, Republican of South Carolina, who said he had no interest in leadership. “I’d rather fight a polar bear with a knife.”