Tanner Ainge, left, addresses the crowd as John Curtis and Joe Buchman listen during a debate in Provo, Utah, for candidates vying for the House seat vacated by Republican Jason Chaffetz. (Leah Hogsten/AP)

The mayor of Provo, Utah, won the race for the Republican nomination Tuesday to fill the seat vacated by retired Rep. Jason Chaffetz against a pair of GOP rivals who portrayed themselves as more ardently conservative.

John Curtis is now well positioned in Utah’s conservative 3rd Congressional District ahead of the Nov. 7 general election, where he will face a Democrat and several third-party candidates.

Curtis faced hundreds of thousands of dollars in negative super PAC ads that sought to portray him as insufficiently committed to lowering taxes and cutting government spending. Many of them highlighted his 2000 run as a Democrat for a state legislative seat.

But Curtis has won plaudits since taking office as mayor in 2010, and polls showed he enjoyed an early lead in the race that the attack ads were unlikely to overcome.

Quin Monson, a Brigham Young University professor and political consultant who advised Curtis, said his win was “entirely attributable to his strong performance as mayor of Provo.”

(Jenny Starrs/The Washington Post)

“He had solved some major problems in the Provo area and had the city pretty united around what he was trying to do,” Monson said. “He has stayed pretty positive. He’s run on his record as mayor.”

Although the race generated hundreds of thousands of dollars in spending and unusually heated political attacks in a state known for its relatively subdued politics, it has flown under the national political radar — largely because President Trump has not been a major factor in the contest.

Unlike other House races decided this year, Democrats are not seriously contesting the heavily GOP district, and unlike in Tuesday’s Senate primary in Alabama, the Republican candidates’ postures toward Trump have not been a crucial factor.

Curtis was ahead with a 41 percent plurality in early returns, outpacing former state lawmaker Chris Herrod and lawyer Tanner Ainge, who both polled around 30 percent with around 77 percent of votes counted.

Herrod won the endorsements of conservative Sens. Ted Cruz (R-Tex.) and Rand Paul (R-Ky.) and positioned himself as the most keenly conservative candidate in the race, targeting the GOP activist base in the special election that was called after Chaffetz announced his retirement in May.

The Club for Growth, a Washington group that calls for lower taxes and spending, poured about $300,000 into supporting Herrod and attacking his opponents — particularly Curtis, with ads lambasting him for supporting fee hikes as mayor and for once running for office as a Democrat. Curtis held a commanding lead in early published polls, but the race tightened after the spate of outside spending.

The special election was conducted primarily by mail in five of the seven counties that make up the 3rd District — including in Utah County, where more than half of the voters in the district reside. Only registered Republicans are eligible to vote in the race, but Utah County elections officials mistakenly sent congressional ballots to unaffiliated voters, as well.

Those voters were notified of the flub, and had the option of appearing in person at a voting center Tuesday to register as Republicans. But the mail ballots in question were segregated and were set to be counted only after all other ballots were counted.

Herrod, who won his place on the ballot at a convention of party activists, emerged as the candidate most openly supportive of Trump — openly touting his vote for the president, while Curtis explained in numerous public forums that he was “unable to support” Trump and chose to write in a candidate instead.

Ainge is the son of Danny Ainge, a household name in the Beehive State because of his basket­ball stardom at Brigham Young University and long careers as an NBA player and executive. The 33-year-old was making his first run for public office with the help of a super PAC, Conservative Utah, that received the bulk of its $290,000 war chest from his mother, Michelle Toolson Ainge.

Both Herrod and Ainge, as well as their super PAC allies, took special aim at what they consider Curtis’s most egregious political sin: his past registration as a Democrat, made ahead of an unsuccessful challenge to a sitting Republican state legislator in 2000. Curtis switched back to the GOP before another run in 2007; his mayoral post is non­partisan.

Curtis sought to play off the attacks, casting them as desperate ploys from outside agitators and setting up a website to offer a detailed rebuttal of their claims. He also won the endorsements of key GOP figures in the state, including popular Gov. Gary R. Herbert.

Chaffetz, who gave up his post as House Oversight and Government Reform Committee chairman when he retired and now serves as a Fox News Channel commentator, did not make an endorsement in the race for his successor.

Monson said the negative ads may have backfired in a state known for relatively genteel campaigning.

“Negative campaigns are effective, but I do think that tone and factual context also matters,” he said. “I do think the negative ads overplayed the hand that they were dealt.”

Curtis will face Democratic nominee Kathie Allen, a physician selected at a party convention, as well as Jim Bennett, the son of the late GOP senator Robert F. Bennett, who is among several third-party candidates running in the Nov. 7 general election.

According to the nonpartisan Cook Political Report, Republicans enjoy a 25-point advantage in the district, putting it among the top 20 most-GOP-leaning seats in the country. Although Allen has raised nearly a half-million dollars after challenging Chaffetz this year, national Democrats have shown no sign of getting involved in the race.

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