The race in Kentucky to succeed Senator Mitch McConnell, an omnipresent force in Republican politics for 40 years, is shaping up to be one of the biggest and most expensive G.O.P. clashes of 2026.
Representative Andy Barr, a Republican who was first elected to Congress in 2012, announced on Tuesday that he was running for the seat that will be vacated by Mr. McConnell’s retirement. Mr. Barr’s candidacy sets up a Republican primary battle against Daniel Cameron, a former state attorney general and a protégé of Mr. McConnell’s.
While Mr. Barr and Mr. Cameron are the only official G.O.P. candidates so far, several other well-known Kentucky Republicans, including Nate Morris, a wealthy businessman with ties to Vice President JD Vance and Donald Trump Jr., have indicated an interest in the seat.
The Republican primary race will revolve around two party titans — President Trump and Mr. McConnell — whose approval among conservatives has sharply diverged. The candidates will feel compelled to demonstrate their pro-Trump credentials as they jockey for the president’s coveted endorsement. That battle is poised to lead to increased public criticism of Mr. McConnell, whose popularity among Republican voters has taken a nosedive.
In a two-minute video on social media announcing his candidacy, Mr. Barr made no mention of Mr. McConnell but brought up Mr. Trump four times.
“I’m running for Senate to help our president save this great country,” he says in the video. He later adds, “Working with President Trump, I’ll fight to create jobs for hardworking Kentuckians, instead of warm and fuzzies for hard-core liberals.”
Public polling in the race’s early, speculative stages has been scant, but a survey released on Monday by Mr. Cameron’s campaign found him leading by a wide margin over the still-undeclared Mr. Barr and Mr. Morris.
That could reflect Mr. Cameron’s stronger name recognition: While Mr. Barr is well-liked in his district around Lexington, Mr. Cameron is better known because of his statewide campaign for governor in 2023, which he lost to Gov. Andy Beshear, a Democrat.
“You can make a plausible case for any of the three winning, but it strikes me that you have to say that Cameron is the favorite,” said Trey Grayson, a Kentucky Republican who lost a primary campaign to Senator Rand Paul in 2010.
Six years ago, an endorsement from Mr. McConnell probably would have ended any primary race for his seat before it began, with the powerful senator who shaped the modern Supreme Court able to anoint a successor and shape the next generation of Republican leadership in the state.
But now it is Mr. Trump’s endorsement that could effectively end the primary contest. He has repeatedly decided Republican races across the country in recent years, and his word will carry great weight in Kentucky, which he won last year by 30 percentage points.
The quickest way to win Mr. Trump’s affection, at least one prospective candidate appears to believe, is trashing the man who currently occupies the Senate seat.
“The last thing Kentucky needs is another puppet for Mitch McConnell running for office,” Mr. Morris said on social media in February. The video remains pinned to the top of his profile.
But while Mr. McConnell’s public image has worsened even in Kentucky, Republican operatives in the state say that voters and local leaders do not share Mr. Trump’s deep hostility toward the senator. Many, if not most, Republican elected officials in Kentucky owe political debts to Mr. McConnell for favors like connecting them with donors and for building the state party into a national force. So despite his unpopularity, bombastic attacks on him could turn off some voters and donors.
Mr. Cameron may have the most difficult task of threading his past support for Mr. McConnell with his assurances to voters that he backs Mr. Trump wholeheartedly.
Well known for years as Mr. McConnell’s preferred heir, Mr. Cameron was reluctant to criticize the senator during his 2023 run for governor. At the same time, he locked up Mr. Trump’s endorsement very early in that year’s Republican primary race.
But almost immediately after Mr. Cameron announced his Senate bid this February, his messaging on Mr. McConnell changed. In a video on social media, Mr. Cameron attacked his former mentor and repeatedly tried to align himself with Mr. Trump.
“What we saw from Mitch McConnell in voting against Pete Hegseth, Tulsi Gabbard and R.F.K. was just flat-out wrong,” Mr. Cameron said, referring to several top Trump appointees. “You should expect a senator from Kentucky to vote for those nominees to advance the America First agenda.”
Mr. Barr’s announcement video includes the famous image of the president after his first assassination attempt, with blood dripping down his face and his fist raised. As the video lingers on the image, Mr. Barr claims that liberals “hate President Trump.” (The would-be assassin’s political views appeared to be muddled, and his motives remain unknown.)
Mr. Trump has not weighed in yet on the race, though he had warm words for Mr. Barr at a White House event this month, saying: “Good luck with everything. I hear good things.”
But Mr. Barr already faces opposition from the Club for Growth Action, a conservative anti-tax group known for spending millions on political campaigns. Even before he announced his campaign, the group broadcast two commercials attacking him as an ally of the president’s enemies and labeling him a “Trump-hating, back-stabbing liberal.”
“Despite promising to bring fiscal responsibility to Washington, Andy Barr has voted to increase federal spending by trillions,” said David McIntosh, the president of Club for Growth Action. “Andy Barr would be a disaster in the Senate, and we will oppose his candidacy.”
In a statement on Tuesday, Mr. Cameron’s campaign echoed the criticism in the Club for Growth Action ads.
“The great Andy Barr rebrand is on, as he now will try and convince Kentucky he’s actually conservative and MAGA,” said Brandon Moody, a consultant for the Cameron campaign. “He’s not. Voters know he went to Washington and sold out Kentucky long ago.”
Mr. Barr enters the race with a sizable war chest, having raised $1.3 million in the first quarter to leave him with more than $5.3 million in cash on hand. Mr. Cameron raised about $500,000 in the month after his announcement and maintained most of that on hand, according to federal records.
His donors also include Kelly Craft, a coal billionaire who ran a bitter campaign against Mr. Cameron for governor in 2023.
On the Democratic side, Pamela Stevenson, the minority leader in the Kentucky State House, is also running for Mr. McConnell’s seat, but she is expected to be a major underdog in the deep-red state.
