WASHINGTON (AP) — Texas Sen. John Cornyn has informed his colleagues that he intends to run for Senate Republican leader, becoming the first senator to announce a campaign after Sen. Mitch McConnell said he will step down from the post in November.

Cornyn, who served as McConnell's No. 2 in leadership before he was term-limited out of the job five years ago, is citing his experience in that role in a statement Thursday to fellow senators announcing his run. But he also is trying to distinguish himself from McConnell, saying, "I believe the Senate is broken -- that is not news to anyone."

"From experience, I have learned what works in the Senate and what does not," Cornyn said. "And I am confident Senate Republicans can restore our institution to the essential role it serves in our constitutional republic."

There has long been speculation that Cornyn, South Dakota Sen. John Thune and Wyoming Sen. John Barrasso -– the "three Johns" -– would vie to replace McConnell, R-Ky., if and when McConnell were to step down. But the longtime leader's surprise announcement on Wednesday that he won't run again for Republican leader after the November elections has jump-started the campaign earlier than expected, almost nine months before GOP senators are expected to gather and choose a new leader behind closed doors.

Cornyn, a former Texas attorney general who was first elected to the Senate in 2002, is a prominent member of the Senate Judiciary Committee and a popular member of the GOP conference who is seen as a steady hand. He has managed to bridge some of the caucus' deep divides in recent years while also occasionally negotiating with Democrats, as he did on bipartisan gun legislation in 2022.

He is also a prolific fundraiser for the party, having raised a total of $13 million for incumbents, the party's Senate campaign arm, and Senate Republican nominees already in the 2024 cycle.

In his statement, Cornyn said he believes he has "built a track record of listening to colleagues and seeking consensus, while leading the fight to stop bad policies that are harmful to our nation and the conservative cause."

Cornyn said he would work to improve communication, try to move spending bills individually and make an effort to include every member in decisions. That's a response to frequent complaints from some senators about massive year-end spending bills and McConnell's top-down leadership approach.

Both Thune, the current No. 2 Republican, and Barrasso, the chairman of the Senate GOP conference, have left the door open to runs after McConnell's announcement. Neither has officially announced a campaign for the job.

Thune told reporters that McConnell's departure leaves "big shoes to fill," but that now is a time "to reflect on his service and and honor him for that. And then we'll we'll go from there." After Cornyn's announcement, a spokesman for Thune said the senator is reaching out to colleagues to discuss "the future of the Senate Republican Conference and what they would like to see in their next leader," but intends on keeping those conversations private.

Barrasso said Wednesday he's focused on the November election and getting a Senate majority. In terms of leadership decisions, "I'm going to talk to members of the conference, hear what they have to say, listen to them in terms of what direction they want to take."

Much of the race for leader is likely to take place through phone calls, one-on-one meetings and private gatherings over the next several months. Unlike the House, where both parties vote for speaker in a public -– and recentlymessy -– spectacle, Senate party leadership is chosen in closed-door conference meetings by secret ballot. Cornyn was already making calls and reaching out to his fellow senators in the hours since McConnell's announcement.

Republican senators haven't chosen a new leader since 2007, when McConnell was elected. That's before most current GOP senators took office.

It is unclear which of the three "Johns" would have an advantage among their peers.

While Cornyn is well liked and has drawn attention for his fundraising, Thune could have the advantage of incumbency, as McConnell's current deputy. Barrasso has tracked furthest to the right of the three, becoming the first of them to endorse former President Donald Trump for the GOP presidential nomination.

Thune and Cornyn have criticized Trump in the past, especially since the Jan. 6, 2021, attack on the Capitol by Trump's supporters. But each eventually endorsed him as it became more likely that he will be the party's presidential nominee this year.

There are certain to be other candidates, as well, including from the wing of the party that is closest to Trump.

Florida Sen. Rick Scott challenged McConnell in 2022 at Trump's urging, winning 10 votes, and he could run again. Scott has said he is focused on his own reelection bid this year, but has appeared open to a run after that.

"I think there's a better way to run the Senate," Scott said after McConnell's announcement. "So we'll see what happens."

On Thursday, Scott said that he and Sen. Ron Johnson, R-Wisc., will soon call for a special conference meeting to discuss the future of the party.

The sudden scramble for the next leader comes as McConnell, 82, had faced louder and increasing criticism from some within his party who have said it is time for a change in leadership. They have criticized McConnell's support for the huge end-of-year spending bills and, most recently, his outspoken backing for aid for Ukraine. A growing number in his conference has opposed the assistance, saying it would be better spent on the U.S.-Mexico border or elsewhere within the U.S.

The Republican leader was also at odds with Trump, whom he has said was " practically and morally responsible " for the Capitol attack. The two haven't spoken since before then, and Trump frequently bashes him publicly.

McConnell acknowledged his critics in his Senate floor speech announcing that he would step down from that role.

"Believe me, I know the politics within my party at this particular moment in time," McConnell said. "I have many faults, misunderstanding politics is not one of them."

He also echoed his critics, calling for a "new generation" to take over.

In the hours after the announcement, as the surprise wore off, many senators praised McConnell's legacy, including his role in the Senate confirmation of three conservative Supreme Court Justices who tilted the court to the right.

Others were more focused on the future.

"This is a good development," said Missouri Sen. Josh Hawley, a frequent McConnell critic. "My question is: Why wait so long?"