WHITESBURG, Ky. — Dewey Gorman, a 59-year-old banker who has struggled with opioid addiction, had just gotten out of the hospital in this tiny central Appalachian city when he heard the word from Washington: His fellow Kentuckian, Senator Mitch McConnell, had delayed a vote to repeal the Affordable Care Act. He felt torn about that.

“It’s broken. It’s broken very badly,” Mr. Gorman said of former President Barack Obama’s signature health care law. “But if they want to take away insurance from 22 million people — a lot of them would come from these mountains. That would be devastating to our area.”

Perhaps nowhere has health care law had as powerful an impact as in Kentucky, where nearly one in three people now receive coverage through Medicaid, expanded under the legislation. Perhaps no region in Kentucky has benefited as much as Appalachia, the impoverished eastern part of the state, where in some counties more than 60 percent of people are covered by Medicaid.

And in few places are the political complexities of health care more glaring than in this poor state with crushing medical needs, substantially alleviated by the Affordable Care Act, but where Republican opposition to the law remains almost an article of faith. While some Senate moderates say the Republican bill is too harsh, Rand Paul, Kentucky’s other Republican senator, is among Senate Republicans who say they are opposed to the current bill for a different reason: They believe it does not go far enough to reduce costs.

Mr. McConnell, who was re-elected handily in 2014, seems committed to his party’s pledge to repeal the Affordable Care Act even if it might hurt some constituents back home. A study last year by the Kaiser Family Foundation found that the percentage of uninsured in Kentucky dropped from 18.8 percent in 2013, the year the health law was put in place, to 6.8 percent — one of the sharpest reductions in the country.

Here in Whitesburg, a city of roughly 2,000 people at the base of Pine Mountain, Mr. Gorman’s sentiment seems to be the prevailing one. In nearly two dozen interviews with health care workers and patients, at the hospital and at a nonprofit clinic run by the Mountain Comprehensive Health Corporation, Kentuckians sounded both fearful and flummoxed by the health care drama on Capitol Hill.

“It makes me very nervous,” said Brittany Hunsaker, 29, a clinic social worker who counsels pregnant women addicted to opioids. “Some of the most vulnerable people that we serve, we may not be seeing any more.”

Several clear themes emerged. Most people said they want everyone covered, and were appalled, as was Mr. Gorman, when they learned the Congressional Budget Office had estimated the Republican plan would leave 22 million more people uninsured over a 10-year period. They are happy that lawmakers are trying to fix Mr. Obama’s health law — rising premiums are a worry for many — but fear that Republicans, in their haste, will make a bad situation worse.

Sorting out the way forward is agonizingly complex. Kentucky’s Medicaid expansion and successes under the Affordable Care Act are largely the result of former Gov. Steve Beshear, a Democrat who is out of office now. Meanwhile, Gov. Matt Bevin, a Republican elected in 2015, is pushing for a Medicaid waiver from the federal government that includes requirements for many beneficiaries to work or participate in job training.

Dr. Van Breeding, the clinic’s director of medical affairs, lamented that the Republican bill in the Senate had gotten mixed up in “party politics,” while patients had been forgotten. He summed up the situation this way: “Senator Paul is worried about the financial aspect of it. Senator McConnell is worried about the political aspect of it. And I’m worried about patients not having access to basic health care.”

Kathy Collins, 50, who suffers from lupus, an autoimmune disease — and who was uninsured until she got Medicaid coverage through the law’s expansion — is among Dr. Breeding’s patients. Sitting in her hospital bed here Tuesday morning, she said she was surprised to hear that Mr. McConnell, whom she had voted for previously, was leading the charge to roll it back.

“He is?” she asked. “Well, then, he’s no good for Kentucky.”

Health care is a growing part of this region’s economy, and people here are also deeply concerned that the repeal will bring job losses to a region already decimated by unemployment from the coal industry downturn.

Dr. Breeding says the number of uninsured patients at the clinic dropped from 19 percent to 4 percent as a result of the health care law. He said Mountain Comprehensive was “barely getting by” financially before the law was passed; business is much better now. Mountain Comprehensive has hired more people and now offers extended weekend hours and an optometry clinic — services that have been financed by revenue brought in from the health law, Dr. Breeding said.

And those services mean more health care jobs.

“If they do what they say they are going to do, then we may lose our jobs,” said Vicki Roland, a surgical nurse. “I think what we have works pretty good for the people. If they revamp it, I’m not sure what’s going to happen.”

Mr. McConnell’s office did not respond to a request for an interview. Despite his constituents’ concerns, Mr. McConnell has little reason to worry about a political backlash; he is widely credited with building the Republican Party in this state, and after three decades in the Senate, his seat is secure. In 2014, he clobbered his Democratic opponent, Secretary of State Alison Lundergan Grimes, winning by more than 15 percentage points.

“He ran on a clear platform to repeal and replace Obamacare, as did Matt Bevin, the governor, as did Rand Paul, the other senator, as did Donald Trump,” said Scott Jennings, a Kentucky Republican strategist with close ties to Mr. McConnell. “And they all have one thing in common: They have overwhelmingly won their elections in Kentucky.”

Still, there has been pushback. On Monday, nearly 100 opponents of the repeal protested outside Mr. McConnell’s northern Kentucky office. On Tuesday, more than a dozen organizations representing health care providers signed an open letter to Mr. McConnell, published in his hometown paper, The Courier-Journal of Louisville, imploring him to “STOP the mad rush to pass this bill” and instead seek advice from health care experts.

“You said you have a ‘responsibility to act.’” the letter said. “We believe you have a duty to act responsively. Kentuckians deserve better.”

The local newspaper here in Whitesburg, The Mountain Eagle, published an editorial assailing Mr. McConnell for putting the bill together behind closed doors. “Why the secrecy, Sen. McConnell?” its headline read.

Dr. Breeding, recently named Country Doctor of the Year by Staff Care, a Dallas-based health care company, shares these sentiments. His message to Mr. McConnell: “Don’t rush it. Bring in the experts. Let’s hammer it out.”

To spend a day with Dr. Breeding is to get a glimpse of his patients’ challenges. His weekday mornings begin at 4:30 a.m., when he arrives at the hospital in Whitesburg. Dressed in his workout gear, he makes rounds, visiting patients whose ailments run the gamut: pneumonia, respiratory failure, colon cancer, lupus, black lung disease, dementia, heart attack, kidney infection and multiple myeloma, a bone cancer.

By 8:30 a.m., after a break for a brisk walk through town, he arrives at the clinic, where his nurse practitioner, Heather Yates, says she sees the health care debate from both sides.

Like her colleagues, Ms. Yates, 35, worries that undoing the Affordable Care Act will hurt patients. But she has had to cope with the high cost of premiums; when her husband was out of work, they qualified for subsidies under the Affordable Care Act but still paid $400 a month for an insurance policy with a deductible of as much as $1,500. Now the couple pays $1,000 a month, with a $6,000 deductible, for a plan that covers all expenses once the deductible is met.

“I’ve got a mix of emotions,” she said. “I do want everybody to have insurance, but I understand what it’s like to pay for it too.”