On July 25, Republicans in Grundy County, Tenn., gathered to hear the candidates in the state’s Senate Republican primary hold forth ahead of Thursday’s election. Most of them kept their comments polite and predictable — and then came Bill Hagerty.
Though there are 15 names on the ballot, Mr. Hagerty, the race’s Trump-endorsed front-runner, singled out his main opponent, Manny Sethi, with an attack-filled tirade, claiming the Mr. Sethi, an orthopedic surgeon, had an “abysmal” record of supporting the Trump agenda and a soft spot for “socialized medicine.”
Amid a chorus of boos from Mr. Sethi’s supporters, Bill Lee, the governor of Tennessee, who has remained publicly neutral in the race, nudged Zach Wamp, a former congressman from the area. “Have you ever seen anything like this?” he asked.
“No,” Mr. Wamp, who has endorsed Mr. Sethi, recalled, responding, “I haven’t.”
Mr. Hagerty, a former private-equity executive who served as President Trump’s first ambassador to Japan, was long considered a shoo-in to replace Lamar Alexander, a much-admired former governor who has served in the Senate since 2003. But Mr. Sethi has run an insurgent-style campaign, casting Mr. Hagerty as insufficiently Trumpian and pulling within a few percentage points of the lead — a sudden turn that has pushed the race in an intensely negative direction, with both candidates accusing the other of such sins as supporting the Black Lives Matter movement or being friends with Senator Mitt Romney of Utah.
The increasingly toxic primary, in a state once known for its genteel politics, highlights the transformation of the Republican Party since Mr. Alexander first captured this seat nearly two decades ago. Whereas Mr. Alexander, 80, centered his first Senate primary message on electoral experience and education policy, his would-be successors have defined their pitches almost entirely in terms of Donald Trump — campaigning not on ideas and vision but on a blanket promise to support the president, and to spurn those who cross him.
In a state where 94 percent of Republican voters support Mr. Trump, it’s not a bad strategy. But for some observers, the lead-up to Thursday’s election has signified the undignified demise of the longtime centrist flavor of Tennessee Republicanism. Politicians who might have once aspired to the bipartisan statesmanship of Senator Howard Baker are now happy to contort themselves to the ideological and dispositional demands of Trumpism.
On paper, neither Mr. Hagerty nor Mr. Sethi are obvious fits in Mr. Trump’s Republican Party, and their campaigns have at times appeared less like efforts to introduce themselves to voters in full than attempts at reinvention.
“The weirdness of how this particular primary has unfolded is that you have two fellows sort of running away from their records — and I mean, they’re good records — in order to show no daylight between themselves and President Trump,” said Keel Hunt, the author of two books on Tennessee politics.
Mr. Hagerty, 60, has the sort of résumé that would make any establishment Republican proud. He served as an economic adviser to President George W. Bush before becoming national finance chair for Mr. Romney’s presidential campaign in 2008. He and Mr. Romney had been friends since the 1980s, when Mr. Hagerty worked for the Boston Consulting Group and Mr. Romney for Bain Capital.
In the 2016 presidential election, Mr. Hagerty first served as a delegate for Jeb Bush, then moved his support to Marco Rubio; only after Mr. Trump sealed the nomination did he come on board with the future president, serving as Tennessee finance chairman of the Trump Victory Committee. Mr. Trump later appointed Mr. Hagerty ambassador to Japan.
The president was among those who encouraged Mr. Hagerty to run for Mr. Alexander’s seat, tweeting in July 2019 that Mr. Hagerty was “strong on crime, borders & our 2nd” Amendment and had his “Complete & Total Endorsement!”
Mr. Hagerty resigned from his ambassadorship four days later.
And when he launched his campaign in September 2019, he did so as a staunch Trump loyalist. He hired the same consultants who ran Marsha Blackburn’s successful, Trump-centered Senate bid in Tennessee in 2018, made the president’s endorsement the cornerstone of his message — and rarely invoked his pre-Trump political experience on the campaign trail.
He also began distancing himself from old friends. The day after Mr. Hagerty announced his candidacy in September, according to filings with the Federal Election Commission, Mr. Romney’s Believe in America PAC contributed the maximum allowed amount to Mr. Hagerty’s campaign — $5,600. Bank records indicate that Mr. Hagerty’s campaign deposited the check. But in October, Mr. Hagerty surprised Mr. Romney by quietly returning the donation in full.
(Neither the PAC’s contribution nor Mr. Hagerty’s disbursement of the refund appears in the Hagerty campaign’s filings, a potential violation of campaign finance law. A spokesman for the Hagerty campaign said, “Once we realized it was deposited, we alerted the bank and we reversed the transaction, because we do not share Senator Romney’s liberal, anti-Trump political positions.”)
And when Mr. Sethi, trying to position himself as the more authentic ally of the president, called Mr. Hagerty “Mitt Romney’s guy” and erroneously claimed Mr. Romney had endorsed him, Mr. Hagerty attacked his former friend, calling him “indistinguishable from Obama” and one of the “most despised names in Tennessee.”
But for some in the state, such denunciations, along with Mr. Hagerty’s ceaseless promotion of Mr. Trump’s endorsement, have only served to highlight how unnatural a mouthpiece he can seem for Trumpism. “It just reads as kind of a campaign tactic — not a lot of heart and soul in it,” said Tom Ingram, a former chief of staff for Mr. Alexander. “Those of us who know him know he’s not an ultraconservative, he’s not a firebrand.”
Mr. Sethi — an Indian-American, Harvard-educated orthopedic trauma surgeon at Vanderbilt University Medical Center — is hoping his own appeals to Mr. Trump’s agenda appear more convincing. In an interview, Mr. Sethi, 42, said he applauded the president’s ideas for “meaningful immigration reform,” including building a wall along the Mexican border, and he praised his performance during the pandemic, adding that, as a physician, his main advice to the president would be to fire Dr. Anthony S. Fauci, the government’s leading expert on infectious diseases.
And while Mr. Sethi offers masks at his events, he said he did not believe it was the role of the government to mandate that people wear them.
He also proudly highlighted the National Republican Senatorial Committee’s efforts to force him out of the race. “When I started talking to these folks in the early spring of 2019,” he said, “it was all flowers and candy, and they were saying, ‘Oh, it’s great, you should run.’ But as I got more serious, they put up these roadblocks.”
He said prominent lawmakers “basically called me and threatened” to blacklist him with major donors, and reminded him that Senator Mitch McConnell, the majority leader, had already made his choice in Mr. Hagerty.
“I couldn’t care less about what Senate leadership thinks about me,” Mr. Sethi said.
Mr. Trump isn’t the only out-of-state politician looming over the race. The contest has become a proxy war of sorts for Republicans looking to gain a foothold in an early, so-called S.E.C. primary state ahead of the 2024 presidential election, with Senator Tom Cotton of Arkansas stumping for Mr. Hagerty and Ted Cruz of Texas and Rand Paul of Kentucky hosting rallies for Mr. Sethi.
Mr. Hagerty also has high-profile Tennesseans, such as Ms. Blackburn and former Governor Bill Haslam, in his corner. And while Mr. Alexander has not endorsed any candidate, he said in a statement that “there’s not a candidate in the country the president has more respect for than Bill Hagerty.”
But rather than enlist such high-profile surrogates to help articulate the choice before voters in terms of policy and experience, Mr. Hagerty and Mr. Sethi have used their final weeks of campaigning to exploit each other’s perceived breaks from Trumpism to the point of parody.
“Every day, you see another negative ad or some new attack,” said Stephanie Chivers, a longtime adviser to Mr. Alexander. “I think it just goes to show how close this thing is. Three or four months ago, I would’ve had Hagerty winning without a doubt, but not now.”
Mr. Hagerty has relentlessly attacked Mr. Sethi for donating $50 in 2008 to ActBlue, a liberal fund-raising platform. One recent Hagerty ad features a wounded veteran who says the donation shows that voters cannot trust Mr. Sethi to defend the American flag.
Mr. Hagerty has also consistently mispronounced Mr. Sethi’s last name as “Set-ee” in ads and speeches, which some Republicans believe is a cynical ploy to remind voters of the candidate’s Indian heritage.
Meanwhile, Mr. Sethi has attempted to link Mr. Hagerty to the Black Lives Matter protests, launching a web ad that points to Mr. Hagerty’s recent position on the board of an investment firm that issued statements in support of the movement following George Floyd’s death at the hands of police in Minnesota. (Mr. Hagerty resigned from his board seat after a conservative news outlet publicized his position.)
Thursday’s election stands to lay bare whether Mr. Sethi’s attempts to cast Mr. Hagerty as a pawn of the establishment are enough to outweigh Mr. Trump’s endorsement; it will also indicate whether a Senate campaign, absent any other message, can succeed on that endorsement alone.
What is perhaps already clear, however, is that the Republican Party that Mr. Alexander long sought to shape — a “governing party,” he once wrote, that translated “principled ideas” into “real solutions” — is not the one he will ultimately leave behind.