Secretary of Health and Human Services Tom Price and President Trump, among others, in the Oval OfficeCarlos Barria / Reuters

President Trump on Wednesday signaled his determination to mount another drive to repeal the Affordable Care Act, but he faces a surprising obstacle: unexpectedly widespread Republican resistance to cutting Medicaid. That hesitation, following decades of GOP efforts to retrench the program, powerfully demonstrates how the party’s growing reliance on economically strained and older white voters is disrupting its ideological compass.

Created in 1965, Medicaid is a state-federal partnership that for most of its history provided health care primarily for low-income children, seniors, and disabled adults. Repeatedly targeted by conservatives, Medicaid has never enjoyed as much political stability as Medicare, the federal health program for seniors.

Both Ronald Reagan and George W. Bush proposed shrinking Medicaid by transforming it from an open-ended entitlement into a limited block grant for states, which would cap federal contributions. In 1995, during the Newt Gingrich era, the Republican-controlled House and Senate voted to convert Medicaid into a block grant despite initial resistance from some moderate Senate Republicans. (Ultimately, only one Republican in either chamber opposed final passage.) But their efforts were blocked when then-President Bill Clinton vetoed the proposal.

In the ACA, former President Barack Obama significantly expanded Medicaid by allowing states to extend eligibility to more low-income, uninsured adults; about 11 million of the 20 million people who gained coverage under Obamacare did so through Medicaid. After the GOP regained the House majority in 2010, it responded by repeatedly passing legislation to undo the expansion and sharply reduce the underlying program itself. But those proposals were blocked either by the Senate or by Obama.

Following those well-worn tracks, this year’s House GOP health bill proposed to eliminate the ACA’s Medicaid expansion and to limit federal payments to states for the underlying program. The combined effect would have slashed federal Medicaid spending by $880 billion over the next decade and eliminated coverage for 14 million people, the Congressional Budget Office calculated. As Trump noted in his Wednesday interview with Fox Business Network, Republicans are counting on those spending reductions to help fund the tax cuts up next on their priority list.

But the Medicaid cutbacks have provoked unanticipated resistance from centrist House Republicans, particularly from states that had expanded eligibility under the ACA. Republican senators from West Virginia, Alaska, Arkansas, Ohio, and Nevada— all expansion states—also questioned the cuts. GOP governors from those last three states, plus Michigan, added their own warnings. None of this guarantees that Republicans won’t eventually coalesce around a plan to repeal Obamacare and squeeze Medicaid. But clearly the program’s politics have grown more complicated for the party.

What’s changed? One factor is that the ACA’s Medicaid expansion has provided clear benefits to providers and patients alike. In states that expanded Medicaid, hospitals are providing much less uncompensated care, which means fewer costs they must shift to paying customers. Rural hospitals have particularly benefited from expansion “because people there have less income and less access to other forms of coverage,” noted Edwin Park, vice president for health policy at the Center on Budget and Policy Priorities, a left-leaning research group.

Working-age adults also report much higher levels of financial and medical well-being in expansion states. A 2016 study by the Commonwealth Fund, a nonpartisan health-research organization, found that far fewer adults reported not seeking attention for a health problem—or problems paying their medical bills—in New York and California, which expanded Medicaid, than in Texas or Florida, which did not.

Even more important than the Medicaid expansion’s benefits may be its beneficiaries. By expanding eligibility, Obama brought into the program millions of low-income working adults, many of them older. That shift has occurred precisely as Republicans have grown more reliant on working-class and older white voters. Obama expanded Medicaid’s reach up the income ladder exactly as the GOP electoral coalition extended further down the ladder. Where the two lines cross, congressional Republicans found that their familiar drive to shrink Medicaid suddenly threatened their own voters.

Amid growing concern about the opioid epidemic, for instance, the Foundation for a Healthy Kentucky recently reported that Medicaid provided substance-abuse treatment for about seven times as many people there in 2016 than in 2014. “We have strong data that people are using the Medicaid coverage,” said Ben Chandler, the foundation’s president. “They are people who are working but still struggling.”

In Ohio, an extensive 2016 state report concluded the Medicaid expansion had helped reduce the state’s share of uninsured working-age adults to its lowest level ever. The study found that 71 percent of those covered in the expansion were white, 56 percent were male, and 58 percent held a high school degree or less. Half were 45 or older, far more than in the traditional Medicaid population. Many of the expansion’s greatest coverage gains came in rural and blue-collar Southeast Ohio counties, such as Belmont, Lawrence, Meigs, Washington, and Gallia. Trump won at least two-thirds of the vote in all those places; in 1996 Clinton carried each of them except Washington.

Before the ACA expansion, Medicaid served few working adults. That made it easy for critics to disparage it as a welfare program for poor families often implicitly portrayed as non-white. Now Medicaid not only serves more working-class adults, but also provides a lifeline to those mostly white, lower-income, rural, and small-town communities beset by rising health challenges and contracting economic opportunity. Long an emblem to conservatives of profligate big government, Medicaid now symbolizes how an evolving Republican Party is struggling to align its ideology with its voters’ material interests.

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