PEORIA, Ariz. — At their final debate, shortly before early ballots went out, five of the Republicans running to represent Arizona's 8th Congressional District tackled their most divisive issue.

Which of them had done the most to support President Trump?

"I'm the only one standing here to support President Trump in the primary," said former Republican legislator Phil Lovas.

"I've defended him in National Review; I've defended him in the Daily Caller; I've said his energy policies give conservatives reasons to cheer," said former corporation commissioner Bob Stump.

"I was a Trump delegate," said former state senator Steve Monte­negro. "I've been on national media, in English and in Spanish, to explain why what he's doing is right."

The battle to replace Trent Franks, who resigned last year after urging a female staff member to become a surrogate mother for his child, has turned less on any traditional conservative issue than on who would best defend the president and enact his agenda.

Republican primaries, which once demanded that candidates please a constellation of interest groups and answer every conservative questionnaire, have increasingly become about the agenda of one man. Trump critics inside the GOP, such as Sen. Jeff Flake (R-Ariz.), Gov. John Kasich (R-Ohio), and Mitt Romney, hold outsized roles in the national political debate. But the candidates bidding for Republican votes can't praise Trump enough.

"President Trump is very popular here, and it's because he's doing a good job," said former state senator Debbie Lesko, another contender for the seat. "I think it's important that we tell voters that we support the president's plans, because some people don't."

In December, when Franks resigned his seat in Phoenix's western suburbs, 12 Republicans jumped in to replace him. The 8th Congressional District, a stretch of resorts, retirement communities, and middle-class neighborhoods, had given 58 percent of the vote to Trump. Franks, one of the most conservative members of the House, had always won by landslides.

Trump, in the 2016 primary, had won handily, but with most Republican voters picking another candidate. He ran behind Sen. Ted Cruz (R-Tex.) with Mormon voters; he lost some suburban voters to Sen. Marco Rubio (R-Fla.) and Kasich. That November, Flake and Sen. John McCain (R-Ariz.) had refused to vote for Trump, and he came closer to losing the state than any party nominee in 20 years.

That was then. Now, in Arizona, the president's magnetic pull has been strong enough to make Joe Arpaio, a legendary sheriff pardoned by Trump, a contender in this year's U.S. Senate primary. At a recent party meeting in Phoenix, candidates down the ballot introduced themselves as Trump allies, and activists gathered petition signatures — one from Arpaio himself — to put the party on record in favor of releasing a congressional memo that they say exonerates the president in the probe of Russian meddling in 2016.

"They all become Trump people at election time," Arpaio said in a short interview.

The fastest-selling item at a merchandise table was a blue hat with the Trump-inspired slogan "Make America a S---hole: Vote Democrat." Rep. Martha McSally (R-Ariz.), the Tucson-area Republican who just entered the race for Flake's seat, seemingly renounced her pre-election criticism of Trump.

"I made a couple of, a very small number of statements about particular statements that were made, and on the spectrum of things, it was very measured compared with a lot of other Republicans," she told the Los Angeles Times at the convention.

In the 8th District, the contenders run along a similar spectrum. Lovas, the former Trump chairman for Arizona, has framed his entire campaign around the president. Lawn signs reproduce a photo of the president and the candidate giving thumbs up; Lovas's logo reproduces the blue and white Trump logo, with his own name swapped in for the president. Campaign materials call him "an unwavering leader who will stand with our president as he makes America great again," and remind voters he was "with Trump at the start," when it was not easy.

Monte­negro, who originally backed Cruz for president, has a different pro-Trump résumé; he is with him on the issues, and he's defended him on TV. Last year, the week that the administration pardoned Arpaio, Monte­negro appeared on CNN to debate Jorge Ramos, smiling as the Univision host accused him of selling out.

"Sheriff Arpaio discriminated against thousands of Latinos," said Ramos, asking how an immigrant from El Salvador, like Monte­negro, could support Trump.

"I do remember that I'm an immigrant myself," said the former senator. "This narrative that the left tries to push, that Republicans are racist — look, if you're watching at home and you think you're seeing a white Republican, you need to adjust your screen."

In an interview, after a party for volunteers at his spartan family home in Goodyear, Monte­negro didn't say whether the exposure had helped him. "We didn't know that this race would be happening when I went on TV last year," he said. "It was just the right thing to do. It's what I've been doing. We, as Republicans, have been able to articulate the constitutional conservative message in English and in Spanish."

Stump, a conservative journalist who jumped into politics in his 20s, had the tougher sell. As in the debate, he admits it: He had not supported Trump. In his defense, it was because he worried that the president was not conservative enough.

"This was a candidate who'd donated to Democrats, who'd dabbled with the Reform Party and who, I thought, would throw the election to Hillary Clinton," Stump said in an interview. "I have been pleasantly surprised, and I tell everyone who asks that I've been pleasantly surprised."

Stump still differed from his competition with a policy critique. The president, he said, was wrong to put a tariff on solar panels — but that's about it. And having vetted his Trump supporters, opponents had already moved on to attacking him for ditching his first name — Christopher — when he began a career in politics among Republicans who remember a long-serving and deceased politician named Bob Stump.

For the rest of the field, Trump's policies are untouchable, even if — as on DACA, or Deferred Action for Childhood Arrivals — they change from week to week. Democrats, who are bearish on their chances in the district, ask if the dynamics can help move some votes. Hiral Tipirneni, the physician who is favored to win the party's nomination this month, said in an interview that she would run against the Tax Cuts and Jobs Act over its minor effect on small businesses and the risk of cuts to Social Security and Medicare.

Republicans had a simpler case to make: Things were going well, so long as nobody got in Trump's way. Every candidate had a version of Trump's promise to "drain the swamp." Richard Mack, a retired sheriff who had run as both a Libertarian and Republican — and who had won his other races far outside the district — said that he jumped into the race because the cluster of "mainstream candidates" made it winnable. His campaign manager nearly got Jim Gilchrist, the former leader of the border-patrolling Minuteman Project, over the top in a California primary.

Over lunch at Applebee's, Mack struggled to think of a problem with the Trump administration. So much had gone right after eight scary years when Barack Obama threatened to "disarm" Americans and shred their rights.

"Out of all the presidents that I've ever known, he's done the most in his first year," said Mack, an NRA Hall of Fame member who carries a Constitution in his shirt pocket. "The economy has been amazing. I'd only complain that he hasn't drained the swamp enough. Jeff Sessions is not a swamp drainer. We still have rogue federal judges, committing crimes."

Mack pondered the question again. "And we need to abolish the IRS."