A staffer and Rep. Jason Chaffetz (R-Utah) eat with staff at In-N-Out Burger after a Feb. 9 town hall in Utah. (Kim Raff/For The Washington Post)

Rep. Jason Chaffetz is not yielding.

When he gavels in his House committee Monday night, the Utah Republican will begin the rare act of dismantling a D.C. law — one that allows for assisted suicide — despite the wrath of District residents who are planning a massive “Hands off D.C.” rally and accuse him of bullying the city to pander to his conservative base.

Chaffetz, chairman of the House Oversight and Government Reform Committee, faced another horde of protesters at a town hall in his Utah district last week, though they were irate because of his inaction.

Why, they demanded to know, was he not investigating President Trump’s financial dealings? In both cases, Chaffetz said, he would not be swayed by angry crowds, phone calls, emails or tweets.

“It doesn’t faze me,” the 49-year-old congressman said at an In-N-Out Burger in his Utah district last Thursday, where he devoured a cheeseburger and french fries moments after his security detail whisked him away from the town hall meeting filled with protesters chanting “Do your job!”

(Claritza Jimenez/The Washington Post)

“It’s a very, very small minority,” he said between sips of a chocolate shake. “It’s a very vocal, very frustrated, scorched-earth mentality that’s not representative of the average person, certainly not in Utah. It might be in San Francisco or Seattle but not here. Not in middle America.”

Instead of Trump, Chaffetz’s targets these days include the District, where he also wants to block the city’s plan to use local tax dollars to help undocumented residents fight deportation. Two weeks ago, he said the best way for the District to gain a vote in Congress would be to rejoin Maryland, a suggestion that infuriated District activists.

Chaffetz, a Mormon who says he is morally opposed to assisted suicide, contends he is fulfilling his responsibility to oversee the District and brushed off any suggestion that he’s catering to conservative voters.

“Everything I do isn’t because of politics,” he said. “I do it because it’s right.”

Eight years after joining Congress, Chaffetz relishes his role at the center of Washington’s rollicking vortex. A ubiquitous presence on cable news shows, the congressman is the GOP’s ever-ready flamethrower, using his committee perch to not only meddle in the District’s affairs but to savage the IRS and Secret Service, and lambaste former secretary of state Hillary Clinton for the Benghazi attack and her use of a private email server.

Yet, since the election, Chaffetz’s refusal to aim his committee at Trump’s financial web has fed accusations that the congressman is unwilling to take on his party’s leader. Not even his public chiding late last week of White House counselor Kellyanne Conway for promoting Ivanka Trump’s clothing line could quell the criticism.

While he was critical of Trump during the campaign, rescinding his endorsement at one point, Chaffetz now crows about the president. After their White House meeting last week, the congressman described Trump’s “natural curiosity” as “refreshing,” and said that “he was very calm, very nice,” and that “it was a thrill to be there.”

People shout to Rep. Jason Chaffetz during his town hall meeting on Feb. 9 in Cottonwood Heights, Utah. (Rick Bowmer/AP)

Chaffetz has repeatedly insisted that he won’t lead a “fishing expedition” on Trump, despite what critics — including nonpartisan watchdogs — contend is ample material.

“Very conveniently, this great advocate and apostle for vigorous oversight of the executive branch announced that maybe it was time to put more energy into reform and not oversight,” said Rep. Gerald E. Connolly (D-Va.), a member of the House committee that Chaffetz chairs.

The Republican congressman is frustrated by criticism that he is kowtowing to Trump, a sentiment expressed in a recent Salt Lake Tribune cartoon which rendered the president as Jabba the Hutt, holding a miniature Chaffetz in his palm.

“I’m with him,” Chaffetz says in the cartoon, beneath the words, “Republicans refuse to investigate Trump’s shady dealings.”

Between visits with lawmakers at the state capitol in Salt Lake City last Thursday, Chaffetz called aides in Washington, pushing them to finalize a letter condemning Conway that he and Rep. Elijah E. Cummings (D-Md.) sent to the Office of Government Ethics.

“Let’s get it out now,” Chaffetz insisted, before composing his own tweet to his 225,000 Twitter followers that described Conway as “wrong, wrong, wrong,” accompanied by a hashtag of “#Donteverdothis.”

Moments later, he bristled as he read on his phone a conservative blogger’s post in The Washington Post that congressional Republicans are not committed to oversight.

“What the crap is this?” he asked. “They wanted me to investigate Trump even before he was sworn in. Really? Come on.”

In addition to his criticism of Conway, he said, his committee is examining the Trump Organization’s Old Post Office lease with the General Services Administration. During the campaign, he reminds audiences, he criticized Trump for not releasing his tax returns.

Chaffetz, who is “leaning toward” a 2020 campaign for governor, voiced no concern over support in his overwhelmingly Republican district, which extends from just south of Salt Lake City to the state’s southern border. “I’m very reflective of my district,” he said, noting that he has won all his elections by massive margins.

Yet Republicans in Chaffetz’s district said they are concerned about the president’s potential conflicts of interest.

“The jury is still out on Chaffetz,” Jeff Nilson, an accountant who has voted for the congressman, said as he waited on line to enter his town hall. “If he challenges him, good for you Jason. Trump has to be answerable for what he does.”

During the recent Republican retreat in Philadelphia, Chaffetz and his wife, Julie, met Trump backstage, an encounter the congressman shared with a photo he posted for his 16,000 Instagram followers.

“ ‘I’m the president, you have a job to do,’ ” Chaffetz said Trump told him. “ ‘You do the oversight. You don’t slow down. You go after everything you want to go after.’ ”

Chaffetz described Trump’s message as “inspiring,” even as he batted away Democratic members’ demands that the committee investigate whether Trump was violating the Constitution’s emoluments clause, which bars presidents from receiving payments from foreign entities.

Chaffetz also has refused to probe Trump’s potential conflicts of interest, saying that federal law exempts the president from such violations. “To dive into somebody’s personal records hoping to find something is not something we have done,” he said.

While Democrats accused Chaffetz of partisanship, Tom Davis, the former Republican congressman from Virginia who chaired the oversight committee, said that “reality” dictates that “you tend to over-investigate the other party and you under-investigate your own.”

“You protect your quarterback, you go after the other guy. That’s always the way it has been,” Davis said.

Yet Norman J. Ornstein, a resident scholar at the American Enterprise Institute, said that ignoring Trump’s foreign ties “is a highly partisan and utterly irresponsible act.”

Chaffetz became the committee’s chairman in 2015, seven years after he won his seat defeating a Republican incumbent with a tea-party-fueled campaign. He made an early impression eschewing earmarks and insisting on sleeping in his Capitol Hill office on a cot that he lugged from Utah.

The congressman still sleeps on the cot, which he stores in a closet along with beef jerky he buys at a Costco in Virginia. His experience in the city is relatively limited. He identified Chinatown as among his favorite neighborhoods “because they have a Five Guys.”

From early in his congressional career, Chaffetz opposed progressive District initiatives such as same-sex marriage and legalizing marijuana, stances that help him maintain high ratings from conservative interest groups.

In recent weeks, District activists have flooded phone lines at Chaffetz’s offices with complaints. D.C. Council members have mocked his interest in District laws and policies by inviting him to their oversight hearings and calling his office to report problems with garbage pickup.

“I would deem him the king of the hypocrites,” said Josh Burch of Neighbors United for DC Statehood. “He is a small-federal-government conservative until it comes to the District of Columbia.”

Chaffetz said the Constitution requires that his committee weigh in on District matters, including what he considers profound issues such as assisted suicide, which he refers to as “killing people.” “I did not go to Congress thinking I would take on death with dignity, but that’s what they put on my plate,” he said.

In interviews in his Utah district, Chaffetz’s constituents expressed vague awareness of his involvement in D.C. affairs, and said they could understand residents objecting to congressional intervention. Yet Gordon Larsen, 62, a retired coal miner who lives 100 miles south of Provo, said he would not fault Chaffetz for “standing up for the morals he has.”

A garrulous pol, his smile framed by dimples, Chaffetz has shown he is unafraid of combat, even when it requires turning on allies. In 2012, he endorsed Mitt Romney for president over his own mentor, former Utah governor Jon Huntsman.

Three years later, Chaffetz surprised congressional colleagues when he unsuccessfully ran against his “good friend” Majority Leader Kevin McCarthy for House speaker. “We need a speaker who can speak,” Chaffetz said, a not-so-subtle dig at McCarthy’s propensity for mangling sentences.

McCarthy’s defenders included Huntsman, who tweeted: “McCarthy just got ‘Chaffetzed.’ Something I know a little something about. #selfpromoter #powerhungry.”

During the presidential race, Chaffetz targeted Clinton’s private emails, a probe he announced on Instagram that he wasn’t relinquishing when he posted a photograph of himself shaking her hand at Trump’s inauguration.

“I thanked her for her service and wished her luck. The investigation continues,” he wrote, a message that outraged Democrats who said it was evidence of the congressman’s viciousness.

“It wasn’t as sensitive as I probably could’ve been,” Chaffetz acknowledged, though he also added that “factually, those sentences are correct.” He also made sure to point out that the post was among his most popular.

In recent weeks, Chaffetz said, a woman he encountered on a street in Washington said, “I hope you will investigate Donald Trump with the same exuberance and intensity that you investigated Hillary.”

“I understand,” the congressman told her. “I think we’ll make you proud.”