WASHINGTON ― Mitch McConnell’s withdrawal from Republican Senate leadership completes Donald Trump’s dominance over the Republican Party as he barrels toward the 2024 GOP presidential nomination despite facing 91 criminal charges across several jurisdictions.

It also reflects the sharply diminished state of the establishment GOP, which for decades advocated for traditional conservatism in the mold of Ronald Reagan and a muscular U.S. foreign policy abroad. Now it’s controlled by the ascendant Trump wing that favors isolationist populism.

McConnell, the longest-serving Senate GOP leader in history, found himself increasingly at odds with the former president’s faction. He faced growing resistance over his support for U.S. aid to Ukraine as it continues to struggle against a Russian military campaign seeking to wipe it off the map. And he was constantly dogged by complaints about his leadership by newcomers who favored more hard-charging tactics.

“Believe me, I know the politics within my party at this particular moment in time. I have many faults ― discerning Senate politics is not one of them,” the 82-year-old senator acknowledged in an emotional speech on Wednesday.

“One of life’s underappreciated moments is to know when it’s time to move on to life’s next chapter. This will be my last term as Republican leader in the Senate,” he added.

The Kentucky Republican stands alone as the highest-ranking elected GOP holdout on endorsing Trump. That will change with the selection of his successor in November. Likely candidates include Senate Minority Whip John Thune (R-S.D.), Senate GOP Conference chair John Barrasso (R-Wyo.) and Sen. John Cornyn (R-Texas). All three men have endorsed Trump, but Barrasso is viewed as more aligned with the former president and the conservatives in the conference.

Although there are still Republicans in the Senate who align more with McConnell’s thinking, they tend to be older than the more recent arrivals in the chamber, underscoring the generational transformation in ideology.

“He has been the standard-bearer of the Reagan era. I’ve appreciated that about him because I am a child of the Reagan era,” Sen. Kevin Cramer (R-N.D.) told reporters on Wednesday. “Our party’s shifted a little bit from that. So I think Mitch is more of a reflection of that change in our party than sort of leading that change.”

McConnell’s critics, meanwhile, celebrated his announcement on Wednesday.

“This is a step in the right direction,” Sen. Josh Hawley (R-Mo.) told reporters. “This conference has got to get back to basics. We’ve got to get back to representing the people who actually elected us. We’ve got to put them ahead of the military-industrial complex.”

“Senator McConnell, one of his great legacies will be the avalanche of corporate money that has disfigured our politics. I hope that we can turn that geyser off,” Hawley added, referring to McConnell’s opposition to campaign finance reform.

McConnell’s tenure as GOP leader has been hugely consequential. He reshaped the federal judiciary and ensured a shift in the balance of power on the Supreme Court, which allowed conservatives to repeal Roe v. Wade. He also shielded Trump from conviction in his impeachment trial after the Jan. 6, 2021, attack on Congress, despite having called the then-president morally responsible for inciting the riot.

McConnell may still announce his support for Trump’s campaign before November, however. His advisers have been in touch recently about a potential endorsement, according to The New York Times.

Democrats weren’t exactly cheering McConnell’s announcement on Wednesday, expressing concerns about who could replace him.

“I’ve disagreed with Mitch McConnell a whole lot more than I’ve agreed with him, but he mostly has fought to keep government functioning,” Sen. Elizabeth Warren (D-Mass.) told HuffPost.

Jennifer Bendery contributed reporting.