A new United States Congress convenes in Washington, DC, on January 3. But for the first time in 18 years, a key Republican leader will no longer be at the helm: Senator Mitch McConnell.
McConnell has led the Republican Party in the Senate since 2007, guiding his caucus through numerous legislative challenges and four different presidencies.
According to experts, his leadership as the Senate’s longest-serving party leader will ultimately serve as a turning point for both Republicans and Congress as a whole.
Under McConnell, US politics moved away from the back-slappers and consensus-builders of earlier eras. Instead, McConnell helped to usher in a period of norm-breaking, hyper-partisan politics that paved the way for figures like incoming President Donald Trump, the leader of the Make America Great Again (MAGA) movement.
“First and foremost, he extended a trend in minority obstruction in the Senate”, Steven S Smith, professor emeritus of political science at Washington University in St Louis, told Al Jazeera.
McConnell, who served as Senate leader for only six of his 18 years, had a Republican majority, according to Smith. The majority of his time has been used to mobilize a Senate minority to stymie the Democratic Party’s agenda.
“Second, he will be known for deepening partisan polarisation in the Senate”, Smith said. “While McConnell is not a conservative or MAGA extremist by today’s standards, he was a deeply partisan leader”.
Some view McConnell as a potential ally for figures like Trump, with whom he has previously had disagreements, despite his support for the Republican Party.
McConnell intends to serve as the Senate’s leader for the remainder of his six-year term despite his resignation. However, it’s still to be seen how much McConnell will support Trump’s ambitious second-term goals.
“I’d be surprised to see him make a public provocative comment. His influence is going underground”, Al Cross, a veteran reporter and columnist who covered McConnell’s tenure, told Al Jazeera.
“I usually play the villain,” I say.
McConnell has served in the Senate for a distinguished career. In 1984, he made his first bid for a seat in the chamber, ousting an incumbent Democrat.
Since then, he hasn’t lost. In 2020, he won his seventh straight term.
Without much opposition, he rose to the top of the Senate. The 2007 retirement of the previous Senate Republican leader, Bill Frist, left the position vacant.
But even from his first days as a Senate leader, McConnell cultivated a reputation as a hardliner and obstructionist.
During his first year as Republican leader, The New York Times described him as operating with “near-robotic efficiency” to smack down Democratic policies, despite leading a minority in the Senate.
According to reporter David Herszenhorn, “Mr. McConnell and his fellow Republicans are playing such tight defense, blocking nearly every bill proposed by the sluggish Democratic majority.”
McConnell quickly embraced his visibility as a partisan warrior, a self-described “grim reaper” for progressive proposals.
For refusing to work across the aisle, he was given the nickname “Senator No.” McConnell himself greeted reporters once by saying, “Darth Vader has arrived”.
“Over the three decades I have been a US Senator, I’ve been the subject of many profiles”, McConnell wrote in the opening lines of his 2016 memoir. “I usually play the villain”.
Smith, the Washington University professor, described McConnell as sparking a “transformation” in the Senate as a result of his hardline approach.
Before McConnell’s leadership, Smith said the Senate only saw “occasional minority obstruction”. But afterwards, the chamber became known in political circles as the “60-vote Senate”.
That nickname is a reference to the 60 votes required to overcome a minority obstruction, otherwise known as a filibuster.
Under McConnell, Smith explained, “acting on legislation of any importance would face minority obstruction and require 60 votes for cloture”.

Bending norms
One of McConnell’s most divisive moments came in 2016, with the death of Supreme Court Justice Antonin Scalia.
Normally, when a justice dies, the sitting president is entitled to nominate a replacement. But Scalia’s death came 11 months before a pivotal presidential election. And Barack Obama, the president at the time, was approaching the end of his last term.
McConnell made a stunning — and swift — political gamble. Within hours of Scalia’s death, the Republican leader announced he would refuse to call a vote to confirm Obama’s chosen replacement.
The American people should be able to choose their next Supreme Court Justice, the statement read. Therefore, this vacancy should not be filled until we have a new president”, McConnell said in a statement.
Left-leaning publications like The Nation decried McConnell’s decision as an assault on the US Constitution. “This refusal exploded norms”, journalist Alec MacGillis wrote in the publication ProPublica.
However, McConnell’s plan altered the court’s power balance for generations to come.
Trump, a political newcomer, was elected in the US in November, setting the stage for even more fundamental changes in Washington.
In the end, Trump announced three right-wing Supreme Court nominees, including one to succeed Scalia. That established a conservative super-majority on the bench, which was anticipated to influence American law for generations to come.
Trump later credited McConnell as his “ace in the hole” and “partner”.
“Mitch recognized, as did I, that since judges enjoy life tenure, the impact of judicial nominations can be felt for thirty years or more”, Trump wrote in a forward to McConnell’s memoir. The ultimate long game is to transform the federal judiciary!

A Trump rivalry
But in the lead-up to a new and emboldened Trump administration in 2025, McConnell has increasingly spoken out against the president-elect and his isolationist “America First” platform.
The two Republican leaders have repeatedly argued heads, which is particularly frosty in their relationship.
Trump has openly called McConnell an “old crow” and vilified his “China-loving wife” Elaine Chao, a slap at her Asian heritage.
McConnell, meanwhile, has countered with his own fighting words, implying parallels between Trump and isolationism in the 1930s.
“We’re in a very, very dangerous world right now, reminiscent of before World War II”, McConnell told the Financial Times in December. “Even the slogan is the same. ‘ America First. ‘ That was what the 1930s were all about.
McConnell is expected to assume the chairmanship of the Senate Appropriations Subcommittee on Defense when he leaves his position as leader in January.
In his new role, he is likely to advocate for expanding the US military in an effort to fend off adversaries like Russia, Iran, and China.
However, experts say McConnell is unlikely to face much resistance from the incoming Trump administration at the age of 82, despite health issues like a recent fall.
I don’t anticipate much in the way of sustained opposition from Senator McConnell because he has left his position of authority and is physically frail, according to Harvard University political scientist Daniel Ziblatt, who spoke to Al Jazeera.
He may cast a dissident vote in a few places that might make a difference, for example. But his track record doesn’t leave me holding my breath”.

No greater institutionalist
Still, Herbert Weisberg, a professor of political science at The Ohio State University, anticipates that McConnell may act as an occasional dissenting voice, particularly as the Senate weighs some of Trump’s controversial nominees for high-level government posts.
“He’d normally want to defer to a Republican president on appointees, but he’ll be cautious on the unusual Trump nominees. He might be willing to vote against a few, but not all of them”, Weisberg told Al Jazeera.
Already, McConnell — a childhood polio survivor — issued a public warning to incoming administration officials to “steer clear of” efforts “to undermine public confidence” in “proven cures”, lest they scuttle their Senate confirmation hearings.
Robert F. Kennedy Jr., the nominee for Trump’s health, was immediately linked to an effort to revoke the polio vaccine’s approval, according to The New York Times.
But a single Republican is unlikely to stall a nomination or piece of legislation, as Steven Okun, an analyst on US politics, government and trade, pointed out.
In the incoming Senate, Republicans have a majority of 53 members. And many in the party are firmly behind Trump’s leadership.
According to Okun, “four Republican senators would be required to stop anything that a future President Trump proposes to the Senate would require,” if there was a united Democratic opposition.
McConnell, Okun said, is unlikely to play the dissident position, “only when Donald Trump takes the most aggressive actions that would be against the US national interest.”
After all, party loyalty has been a key tenet of McConnell’s leadership. And the journalist Cross believes McConnell won’t want to miss a chance to influence presidential policy using the Senate’s authority.
“I can’t think of any greater institutionalist than Mitch McConnell”, Cross said. “He loves the Senate, it’s what he’s aspired to. He doesn’t want to give up its role in advice and consent”.