Mitch McConnell of Kentucky will step down as Republican leader in the US Senate at the end of this year, a move that will shake up US politics yet more in a tumultuous election cycle.McConnell is 82 and the longest-serving Senate leader in history. He is also a highly divisive figure in a bitterly divided America and the subject of fierce speculation about his health after recent scares in public.Aides said the decision to step aside, which McConnell announced on the Senate floor on Wednesday, was not related to his health.“One of life’s most underappreciated talents is to know when it’s time to move on to life’s next chapter,” McConnell said. “So I stand before you today … to say that this will be my last term as Republican leader of the Senate.”From the White House, Joe Biden, who was a senator alongside McConnell for more than 20 years, said: “I’ve trusted him and we have a great relationship. We fight like hell. But he has never, never, never misrepresented anything. I’m sorry to hear he’s stepping down.”McConnell was concurrently the subject of reporting about when he will endorse Donald Trump for president in his expected rematch with Biden this year.McConnell and Trump have been at odds since 6 January 2021, when Trump incited supporters to attack Congress in an attempt to stop certification of Biden’s win. McConnell voted to acquit the former president in his resulting impeachment trial, reasoning he had already left office, but excoriated him nonetheless. Trump responded with attacks on McConnell and racist invective about his wife, the former transportation secretary Elaine Chao.Nor did Trump leave the scene, as McConnell apparently thought he would. Withstanding 91 criminal charges, assorted civil defeats and attempts to remove him from the ballot for inciting an insurrection, Trump stands on the verge of a third successive nomination.On Wednesday, Jamie Raskin, a Maryland Democrat and House impeachment manager, told reporters: “I have a lot of feelings about Mitch McConnell from the second impeachment trial because I felt that he was appalled by what Donald Trump had done, he knew the truth about what Donald Trump had done, and yet he couldn’t bring himself to vote to convict along with seven other Republican colleagues who joined the Democrats.”“I understand [McConnell has] been in a tough situation with Donald Trump taking over his party and I think he’s tried to do what he can but he didn’t show the ultimate courage, which would have been to vote to convict him, to find enough other senators so that we wouldn’t be back in this nightmare again with Donald Trump.”Amid gathering warnings of the threat Trump poses to American democracy, all bar one of McConnell’s leadership team have endorsed Trump regardless. The holdout, Joni Ernst of Iowa, has indicated that she could still do so.“Believe me,” McConnell said in the Senate chamber, “I know the politics within my party at this particular moment in time. I have many faults. Misunderstanding politics is not one of them. That said, I believe more strongly than ever that America’s global leadership is essential to preserving the shining city on a hill that Ronald Reagan discussed. As long as I am drawing breath on this earth, I will defend American exceptionalism.”McConnell entered the Senate in 1985, when Reagan was in the White House.“When I got here,” McConnell said, “I was just happy if anybody remembered my name. President Reagan called me Mitch O’Donnell. Close enough, I thought.”McConnell was elected to lead Senate Republicans in 2006. He was majority leader from 2015 to 2021, a momentous term in which he not only coped with Trump but secured three supreme court justices, tilting the court decisively right.He did so by upending Senate rules. First, McConnell refused even a hearing for Merrick Garland, Barack Obama’s nominee to replace the conservative Antonin Scalia, saying the switch would come too close to an election and voters should indicate the sort of justice they wanted. After Trump won the White House, McConnell filled the seat with the Catholic, corporately aligned Neil Gorsuch.McConnell next oversaw the appointment of Brett Kavanaugh, an anti-Clinton operative and aide to George W Bush, to replace Anthony Kennedy. A staunch conservative replaced a frequent swing vote, even after a tempestuous confirmation.McConnell was memorably reported to have said he stood “stronger than mule piss” behind Kavanaugh, despite the claim by Christine Blasey Ford, a college professor, that the nominee sexually assaulted her at a high-school party, an allegation Kavanaugh denied.Finally, at the very end of Trump’s term, McConnell abandoned the argument he used to block Garland and rammed the hardline Catholic Amy Coney Barrett on to the court in place of Ruth Bader Ginsburg, a hero to progressives.On Wednesday, Adam Parkhomenko, a Democratic strategist, told followers they should “never forget” what McConnell “did to the supreme court and this country”.Carl Tobias, a law professor at the University of Richmond, Virginia, said McConnell would “enjoy a tremendous legacy”, not only through his supreme court work, which led to epochal decisions including Dobbs v Jackson, which removed the federal right to abortion, and rulings on gun control and affirmative action every bit as divisive.“McConnell also contributed substantially to Trump’s nomination and confirmation of 54 ideologically conservative appeals court judges and the filling of all 179 appeals court judgeships at one point in Trump’s tenure,” Tobias said. “The last time that the courts had all of the active judges was in the mid-1980s.”McConnell said he still had “enough gas in my tank to thoroughly disappoint my critics. And I intend to do so with all the enthusiasm with which they have become accustomed.”His desire to win back the majority – in a chamber skewed in Republicans’ favour – will fuel his final months as leader. A new leader will be elected in November to take over in January, he said.Leading contenders to succeed McConnell – and to attempt to match his ruthless politicking and powerful fundraising – include his No 2, John Thune of South Dakota, and two more leadership figures, John Cornyn of Texas and John Barrasso of Wyoming. Last November, McConnell defeated a challenge from Rick Scott of Florida.Among Republican tributes, Thune said simply: “He leaves really big shoes to fill.”Among Democrats, Chuck Schumer of New York, the Senate majority leader, said he and McConnell “rarely saw eye to eye … but I am very proud that we both came together in the last few years to lead the Senate forward at critical moments when our country needed us, like passing the Cares Act in the early days of the Covid pandemic, finishing our work to certify the election on January 6, and more recently working together to fund the fight for Ukraine”.Americans, it seems sure, will remember Addison Mitchell McConnell III in very different ways.The Lincoln Project, an anti-Trump group founded by former Republican operatives, said McConnell would “go down in history as a spineless follower who cowered to a wannabe dictator clown. He chose the power of a tyrant over protecting democracy.” More