US Senate Minority Leader Senator Mitch McConnell, Republican of Kentucky, walks to his office from the Senate floor after announcing he is stepping down as the Republican leader at the US Capitol
US Senate Minority Leader Senator Mitch McConnell, Republican of Kentucky, walks to his office from the Senate floor after announcing he is stepping down as the Republican leader at the US Capitol AFP

Mitch McConnell, the veteran and powerful US political tactician who has advanced conservative causes for years and been a strong defender of aid to Ukraine, announced abruptly Wednesday that he would leave his post as leader of the Republicans in the Senate later this year.

His speech to the chamber came as a surprise and prompted lawmakers from both parties to give him a standing ovation, though he did not say if he was giving up his seat from the state of Kentucky, which he has held since 1985.

"I stand before you today, Mr. President and my colleagues to say this will be my last term as Republican leader," McConnell, 82, said as he signaled the end of his tenure as the longest-serving Senate leader in American history.

McConnell has been the largely unchallenged leader of Republicans in the Senate since 2015 and was in the front line of the party's battles against the policies of Barack Obama from 2009-2017.

He was instrumental in bringing Donald Trump to power in January 2017 as the party underwent dramatic changes, before falling out with Trump over the former president's baseless claims to have won the 2020 election.

For years McConnell relished his self-given monicker as the "Grim Reaper" -- one who doomed the hopes of Democratic lawmakers.

In the Senate he waged a fierce fight to enact a right-wing agenda, notably with the appointment of three Supreme Court justices who led the tribunal to end the federal right to abortion in 2022.

A consummate backroom negotiator with a thick, rumbling southern drawl, he also emerged as one of the most outspoken advocates of US military aid to Ukraine after the Russian invasion.

But he has had to grapple with a fractured, Trump-dominated party that came to shun cooperation and the traditional US leadership role on the international stage, opting to look inward and put American interests first and foremost.

The shift turned more pronounced in recent weeks as President Joe Biden's request for $60 billion for Ukraine stalled in Congress as Republicans in the House demanded action first on an immigration crisis at the border with Mexico.

McConnell projected an image of quiet austerity that clashed with his reputation as a tough political operator and strategist.

Under the presidency of Biden, with whom he served in the Senate for years, McConnell also worked for the passage of bipartisan legislation on infrastructure and other issues backed by both parties.

Last summer however concerns arose about McConnell's health, as several times he froze up while speaking in public and fell awkwardly silent.

In March he was hospitalized after he fell during a dinner and suffered a concussion and a broken rib, forcing him to leave his job for six weeks.

The incident reignited criticism that Congress is dominated by white men in their 70s and 80s who cannot bear to retire.

But McConnell had steadfastly refused to resign and rejected suggestions that he was no longer healthy enough to serve.