From left, Tanner Ainge, John Curtis and Joe Buchman take part in a debate. (Leah Hogsten/AP)

A House special election has attracted hundreds of thousands of dollars in spending, a big-name outsider candidate and unusually heated political attacks in a state known for its relatively subdued politics.

But as voters in Utah’s 3rd Congressional District head to the polls Tuesday to start choosing a successor to retired Republican Jason Chaffetz, the race has garnered only a fraction of the national scrutiny given to other contests this year.

That’s largely because the seat is of limited utility as a bellwether for President Trump. 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.

Instead, Tuesday’s GOP primary in Utah is set to be decided along more familiar lines of ideology and sensibility in a state whose Republican voters have long had an uneasy relationship with Trump.

“The short answer is, President Trump has not been much of a factor in this race,” said Jason Perry, director of the Hinckley Institute of Politics at the University of Utah. “The answer from these candidates that has been resonating with Utahns is ‘We hold everyone accountable,’ and that is the extent of the influence of the Trump administration so far on this race.”

The front-runner for the Republican nomination, according to published polls, is Provo Mayor John Curtis, who has built a pro-business record during 6½ years in office and has attracted support from the party establishment in and around the growing high-tech center south of Salt Lake City.

But despite declaring himself “the most conservative mayor that the state’s ever had” in an interview with the Salt Lake Tribune, Curtis’s bona fides have been sharply challenged by former state Rep. Chris Herrod and businessman Tanner Ainge — both of whom have sought to outflank Curtis from the right and have gained on Curtis in recent polls.

Herrod, who won his place on the ballot at a convention of party activists, has emerged as the candidate most openly supportive of Trump — though he has also won the endorsements of Trump’s former presidential primary rivals, Sens. Ted Cruz (R-Texas) and Rand Paul (R-Ky.).

More crucially, Herrod has the backing of the conservative Club for Growth, which has spent nearly $300,000 to support him and attack his foes through mailers, radio spots and TV ads.

One radio spot praised Herrod and then took aim at Curtis’s appearance: “He’s perfectly posed. Shirt carefully untucked. Slick. But his record doesn’t look nearly as good.”

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 is 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, have taken 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 later switched back to the GOP before another run in 2007; his mayoral post is non­partisan.

Like Ainge, Curtis won his spot on the primary ballot by collecting voter signatures, bypassing a party convention dominated by conservative activists. He has won the endorsement of Utah’s popular Republican Gov. Gary R. Herbert and has sought to brush off the super PAC attacks.

In a recent YouTube clip called “#DONTDCMYUTAH,” Curtis called the mailers sent attacking him “junk in every sense of the word” and demonstrated other uses for them — shooting at them in target practice, stepping on them as floor mats and suggesting they can be shredded and used as garden mulch: “Made with real crap but without the smell.”

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

The winner of Tuesday’s GOP primary 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. While Allen has raised nearly a half-million dollars after challenging Chaffetz earlier this year, national Democrats have shown no sign of getting involved in the race.

“This is one of the more reliably red districts in the country, and there are other great candidates out there, but the winner of the race tomorrow is going to be very well positioned for the general elections,” Perry said.