In the days since he helped fellow Republicans unveil their long-awaited health care plan, Congressman Greg Walden has watched nearly every major group in the medical and insurance industries come out against it.

Now some of that pushback is coming from rural Oregon, including his own district, which could be hit hard by the plan.

The massive expansion of the Medicaid program under the Affordable Care Act gave rural hospitals a badly needed infusion of new paying customers. The American Health Care Plan lawmakers released Monday would roll it back, and then some.

"I'm in hardcore Republican territory, but there's no question the expansion of coverage for people who didn't have coverage before is a marvelous thing," said Charlie Tveit, chief executive officer of Lake Health District, which runs a hospital in remote Lakeview. "Without doubt it helped our hospital. It allowed us to expand our operation a little, and it reduced our charity care."

The Republicans' repeal and replacement legislation for the Affordable Care Act dramatically changes the health care landscape. It drops the individual mandate requiring all adults to buy health insurance and institutes dramatic tax credits and subsidy changes. It also retreats from the massive 2014 Medicaid expansion that added hundreds of thousands of Oregonians to the federal system's rolls and slashes the federal contribution to that program after 2020.

Like Walden, Tveit sees the need to rein in government spending on health care. But the cutbacks outlined in the Republican plan -- which by some estimates could cost 10 million Americans their coverage -- has him worried. "When we look at what the Republicans delivered, we're all concerned."

A who's who of Beltway power players -- mainstream medical and insurance industry groups, the progressive fringe and Tea Party conservatives alike -- have condemned the GOP plan. You know you've missed the legislative sweet spot when the American Medical Association, AARP, big insurers, Elizabeth Warren and the Koch brothers are united against your bill.

But perhaps the most important constituent, President Donald Trump, has offered a most enthusiastic endorsement. And it took just 18 hours for Walden and Speaker of the House Paul Ryan to get the bill through the House Ways and Means Committee.

Burns, Oregon, is a long way from Washington, D.C. As Dan Grigg, chief executive officer of Harney District Hospital acknowledges, Burns is a long way from anywhere. When you're two hours from Bend and two-and-a-half hours from Boise, it's vitally important for local residents to have a high-quality hospital in their midst.

That was the message Grigg tried to convey to Walden in a March 8 letter. The Medicaid expansion pushed Harney District Hospital into the black for the first time in years and allowed it to go on a small hiring spree: two doctors.

The financial numbers illustrate the medical center's dramatic turnaround in the expansion years. Harney District Hospital posted total patient revenue of $11.6 million in the second quarter of 2016, the most recent period available. That's 38 percent higher than the same quarter before the expansion.

Now Grigg is worried the hospital's turnaround could come to a skidding halt. "If the Medicaid funds went away, it certainly will create some significant financial challenges," he said. "If that expansion population didn't have coverage, we'd likely still be taking care of them. It would be real tough."

The same is true at small hospitals across the state. Dr. Carla McKelvey, a prominent pediatrician in Coos Bay, said the Affordable Care Act not only reduced the rate of uninsured Coos County residents from 12 percent to 6 percent, it stabilized hospitals in Reedsport, Coquille, Bandon and Gold Beach. "I fear without the [Affordable Care Act] they will close," she said.

The Oregon Association of Hospitals and Health Systems said "rural hospitals' financial picture has improved since the full implementation of the ACA, but their situation still remains largely precarious." Fourteen Oregon hospitals posted negative operating margins in 2015, compared with 23 in 2013.

Walden declined to comment for this report. But on Wednesday he said that all the handwringing about the legislation is misplaced.

"It's tough to do entitlement reform, it's tough to make these changes, but I think at the end of day, seniors are going to be fine," he told The Washington Post. "If you're on Medicaid today, you'll be on Medicaid tomorrow. States can intercede here and help out. So there's more to this story."

But to fill the funding gap that would be created if the Republican plan is enacted, states would need billions of dollars, money state officials say they don't have.

"I think it's preposterous to say the states can just step up," said Nathan Johnson, chief policy officer at the Washington State Health Authority. "We're not in a position to take on that obligation.

The federal government liberalized qualifying standards for Medicaid so that people earning 133 percent of the federal poverty level could get coverage. In Oregon, about 400,000 people joined the program, in Washington state, 700,000.

In some rural counties, more than 30 percent of the population went on Medicaid. Ironically, the Oregon counties that voted most heavily for Trump - who made dismantling Obamacare a central pledge of his campaign -- now stand to lose the most in terms of access to health care.

The numbers are huge. Between them, the state and federal governments are spending $6.5 billion a year for coverage for nearly a million people, just in Oregon.

Tveit, the hospital director in Lakeview, said that's a troubling number. "I think a lot of people who voted for Trump were of the belief that giving away that kind of largesse is unsustainable," he said. "Free lunches are great. But someone's got to pick up the tab."

Oregon already faces a funding crunch this year as the federal government's share of the cost went from 100 percent to 95 percent, creating a new $350 million obligation for the state.

Under the Republican plan, federal funding for the expansion population wouldn't disappear. Rather, in 2020, that share would decline in Oregon from 95 percent to 65 percent for new and returning members. In some states, like California, the federal share would shrink to 50 percent.

It's clear that Walden and Ryan are walking a political tightrope. Walden spent part of last week trying to win over the Freedom Caucus and other hard-right elements in Congress who dismissed the plan as Obamacare-lite. Walden told conservative radio host Hugh Hewitt that opponents of the bill should chill out -- that more legislation could follow that will make the overall package more free-market oriented.

Speculation grew late in the week that Tea Party Republicans wanted the rollback of the Medicaid expansion to start immediately instead of waiting for 2020 and that Trump was willing to consider that possibility. Walden reportedly insisted on the three-year phase-in.

That was hardly comforting to liberal advocates of universal coverage, like Gov. Kate Brown. On Wednesday, she called on Congress to delay voting on the health care bill and said she's directed Oregon health care and insurance regulators to work up an analysis on the bill's probable impact.

"Today, as a result of the Affordable Care Act, approximately 500,000 Oregonians have gained health care coverage through Medicaid or receive financial support to buy private health insurance," Brown said. "In just three years, our state's uninsured rate has dropped from 15 to 5 percent. In that same time, 23,300 health care jobs have been created in Oregon. These are vital economic drivers in rural parts of our state."

McKelvey, the Coos Bay pediatrician, said she too wrote to Walden urging him to rethink the rollback on the Medicaid expansion.

"I've met him several times, I think he's a thoughtful man, and I think he really cares about rural Oregon," she said. "I would ask him what is his plan to support this population?"

-- Jeff Manning

503-294-7606, jmanning@oregonian.com