When Representative Chris Stewart spoke with constituents by videoconference on Wednesday, a woman, who said she had gotten insurance for the first time in her life through the law, asked, “Poor people need it and you’re against it — why?” Congressional offices have been bombarded with calls, emails and social media messages, including from some constituents who had never been moved to contact them before.
“Certainly this is something that’s unusual in Utah,” said Jason Stevenson, who is the education and communications director at the Utah Health Policy Project, a research group that has a federal grant to help people enroll in marketplace coverage. He said he had noticed a change in attitudes and energy.
Concerned House and Senate aides have reached out to Mr. Stevenson’s group in recent weeks, he said, to request meetings and detailed information about enrollment trends here and how various Republican proposals, like high-risk pools for people with pre-existing medical conditions, would work. In the past, he added, “we really had to push” to get their attention.
“I would say the phone calls are rattling them,” he said.
Many customers of the insurance exchanges here are young, middle-class families who rely on marketplace plans because they are self-employed or students, or they cannot afford the coverage offered through their jobs, Mr. Stevenson said.
Other marketplace customers, like Ms. Nelson, took jobs that do not offer health insurance because they could get coverage through the Affordable Care Act.
Ms. Nelson said the option had allowed her to work at a job she loved, at a small private school. She has called and written Representative Mia Love, the Republican who represents her district, because she is afraid she will have to change jobs if the law is repealed.
Catie Weimer, a record store employee in Salt Lake City who was given a diagnosis of narcolepsy after getting a subsidized marketplace plan last year, said she had joined a group called Utahns Speak Out, which she found on Facebook, as she grew increasingly anxious about the prospect of losing her insurance.
Now Ms. Weimer, who is 30 and said she had voted for Hillary Clinton, is helping administer the group’s Facebook page and helped plan a “Utah Town Hall for All” last weekend. Every member of the Utah delegation was invited, but none attended.
The health law is by no means perfect in Ms. Weimer’s mind; even with a subsidy, her monthly premium jumped to $95 this year, from $47, and she has a $2,500 deductible. Her insurer, Molina Health, has refused to pay for a drug, Xyrem, that helps her function, so she gets it through a charity program. Still, she said, she would have no diagnosis or access to specialists without her coverage.
“I knew Orrin Hatch, but I didn’t even know the name of my other senator before this,” Ms. Weimer said, referring to Senator Mike Lee, like Mr. Hatch a Republican. She said she had called their offices repeatedly in recent weeks, adding, “The threat of something this bad wasn’t ever there before.”
Many Utah voters were deeply uncomfortable with President Trump’s candidacy, though he still won the state with 45 percent of the vote compared with 27 percent for Mrs. Clinton and 21 percent for Evan McMullin, a conservative Mormon who ran as an independent.
Mary Wood, a divorced mother of two who works three part-time jobs, none of which offers health insurance, said she had voted for Mr. McMullin as part of “this movement in Utah of people who had a hard time completely putting themselves behind either Trump or Hillary.” But now, she said, with Mr. Trump pushing for a repeal of the health law and for other policies she opposes, her vote is “one of the biggest regrets of my life.”
She pays $75 a month for a plan that covers her family of three, receives a subsidy of $558 and worries about the type of replacement that was laid out in a draft bill recently published by Politico. That plan would provide age-based tax credits that would be most generous for older people; Ms. Wood, 39, fears it would provide her with far less financial assistance than the income-based subsidies she gets through the Affordable Care Act.
“I tried to call Orrin Hatch, and his voice mail box was full,” she said. “I would have told him, ‘Look, this is going to personally affect me and my children, if you repeal the A.C.A.’”
In a statement, Mr. Hatch said the law was “imploding from within,” adding, “I’ve spoken to Utahns from all over the state and from all walks of life, and the vast majority favor our efforts to repeal and replace Obamacare with patient-centered reforms that lower costs.”
Although much of the support for the health law here appears rooted in Salt Lake County, which is far more liberal than most of Utah and voted for Mrs. Clinton in November, resistance to repeal also appears strong in regions where a lot of people work seasonal jobs in tourism and recreation and rely on the individual market for health coverage.
“Due to pent-up demand, it was like ‘The Walking Dead’ coming out of the woodwork, seeking cures,” said Charles Kulander, an insurance broker in Moab, describing the demand for coverage after the marketplace opened in 2013.
Frustration with the law in Moab, he said, is focused on the state’s refusal to expand Medicaid to adults earning up to 138 percent of the poverty level, as the health law allowed, and the fact that federal premium subsidies are available only to people earning up to 400 percent of the poverty level.
As in all 19 of the states that have not expanded Medicaid, tens of thousands of people in Utah are stuck in a coverage gap, eligible for neither Medicaid nor premium assistance under the law. Many still rely on charity care offered by places like the Volunteer Care Clinic, a busy free clinic run by doctors and nurses in Provo two nights a week.
Even the most conservative parts of the state have residents who have benefited from the law or know someone who has. When The New York Times asked Utah readers to share their experiences, hundreds who filled out the online questionnaire said they wanted the law to survive. Many came from Republican strongholds like Utah County, home of Provo, where only 14 percent of voters backed Mrs. Clinton last fall.
A healthy minority of respondents said they opposed the law and wanted it repealed, usually citing high costs and few choices for coverage. Three insurers are participating in the marketplace here this year, but most counties have only one. Premiums for midlevel plans rose here by 20 percent on average this year, with higher increases in rural areas, but about 85 percent of marketplace customers qualify for subsidies to help with the cost, often substantially.
Enrollment here grew by 12.3 percent to 197,187 this year, a time when nationwide enrollment dipped slightly, according to preliminary federal data. And the gains were not concentrated in left-leaning parts of the state: Utah County, where nearly 60 percent of voters are Republican, experienced a 26.7 percent enrollment increase through the end of December, Mr. Stevenson said, while Salt Lake County’s enrollment grew by only 2.3 percent.
Still, many Utah residents buy insurance outside the marketplace and receive no subsidy, usually because their incomes are too high to qualify. Mike Robertson, who lives in Orem with his wife and three children, said he had switched plans this year to avoid a 66 percent increase in premium costs but still paid $1,200 a month for a family plan with no subsidy.
“Doesn’t feel like insurance. Feels like punishment,” he said.
Ms. Nelson said some of her conservative friends’ and relatives’ opposition to the law softened when they realized she was benefiting from it.
“Some people have said, ‘You know, Kim, you make us feel better about A.C.A.,’” she said. “They look at me and think, ‘She used to be a runner. She never drank or smoked, but you know what, she got breast cancer.’”