As Obamacare’s rollout floundered in 2013, President Barack Obama repeatedly took solace in Kentucky’s success. The state’s exchange, known as Kynect, worked virtually glitch-free and helped sign up tens of thousands of uninsured people. Obama even invited outgoing Gov. Steve Beshear to his 2014 State of the Union and praised him as “a man possessed” by his crusade to make the president’s law work in a state where the Obama himself isn’t particularly beloved.

Gallup polling shows Kentucky saw the second biggest drop in its uninsured rate in the country, behind only Arkansas.

Yet, Republican gubernatorial nominee Matt Bevin, a tea party favorite who narrowly won a brutal primary last month and could run a competitive general election race, has made eliminating the state’s Obamacare programs — and sharply curtailing the ranks of the newly insured — a central plank of his platform. If he wins this November, more than half a million people who got covered through the exchange or an Obamacare-prescribed expansion of Medicaid could find themselves in health care limbo.

Beshear, a Democrat and the only southern governor to fully implement and champion the cause of the Affordable Care Act, is furious.

“I am not going to allow someone to become governor of this state who wants to take us back to the 19th century,” he said in a phone interview. “For a serious candidate for governor to be advocating a simple repeal of the whole program without offering any kind of alternative which will continue health care for these people is irresponsible.”

Bevin shrugs off the criticism. He insists that Obamacare is coverage in name only — that Kentuckians still lack access to high-quality health care, partly because Medicaid pays doctors such low rates, partly because he says too many people rely on emergency rooms. He wants to abolish Kynect — which he calls “redundant” and too expensive — and intends to give enrollees a year to sign up for subsidized coverage through HealthCare.gov, the federal portal for more than three dozen states. But that assumes the Supreme Court doesn’t abolish subsidies though HealthCare.gov in its decision in King v. Burwell, which is expected later this month.

That doesn’t worry Bevin. “You’re worrying about a hypothesis,” he said. “Let’s let the Supreme Court rule.”

Bevin would also put an end to Obamacare’s Medicaid expansion, and many of the hundreds of thousands of low-income Kentuckians who had signed up would simply be deemed ineligible to renew.“When you reenroll, you may or may not have access to Medicaid going forward,” he told POLITICO. “People are not on it for extended periods of time. It’s not meant to be a lifestyle. It really isn’t. The point of it is to provide for those who truly have need.”

A Bevin win would ripple beyond Kentucky, where Republicans running for president and Congress are still working to articulate what health care in a post-Obamacare America might look like — presuming they could win a tricky repeal of the health law in the first place. A Bevin administration would be the first to actively undo a state exchange, becoming a test case for states looking to untangle themselves from Obamacare.

On the other hand, if Bevin loses, White House allies are sure to paint the election as a win for Obamacare.

“Because it is such a clearly red state at this moment, if Bevin were to lose and a key part to of his campaign is to rescind coverage as it exists today, it probably will be perceived as a victory for the Affordable Care Act,” said Ron Pollack, executive director of the advocacy group Families USA.

State Attorney General Jack Conway, the Democrat running to succeed the term-limited Beshear, would largely continue Beshear’s policy of promoting Kynect, while trying, rhetorically, to distinguish it from Obamacare.

The state’s most powerful Republicans, Sens. Mitch McConnell and Rand Paul, have been among the most vocal champions of Obamacare repeal, but Democrats here have managed to brand Kynect as distinct from the much-maligned health law.

“Jack Conway’s top priority is growing the economy and helping businesses create jobs, and making sure Kentuckians have access to healthcare is an important component of that goal,” said Conway spokesman Daniel Kemp. “Jack wants to make sure that the hundreds of thousands of Kentuckians who now have health insurance through Kynect, especially kids, keep their health insurance — not play politics or push an ideology that’s out of touch with Kentucky’s values.”

Which doesn’t mean he wants to talk about it very much. Conway is in the tricky spot of embracing Kynect while trying to keep his distance from Obama and Obamacare, a term that still generates ire among Kentucky residents. A September 2014 Marist poll found that 61 percent of registered Kentucky voters had an unfavorable impression of Obamacare. Only 17 percent had negative feelings about Kynect.

When asked directly about Kynect, Conway tends to hail his state’s efforts while indicting Washington, despite the fact that Obamacare created the state exchange.

“The people of Kentucky have distinguished between the inability of Washington to get it right and what Kentucky did,” he said in an interviewwith the Associated Press last year.

The campaign declined to make Conway available for an interview. Some political observers think he will steer clear of talking health care on the trail.

“I think Conway will avoid talking as much about health care as he can, because he’s going to be running away from Obama as much as he can,” said Al Cross, director of Kentucky’s Institute for Rural Journalism and Community Issues.

It may be hard to avoid, particularly as insurers’ preliminary rate requests suggest that health insurance premium could rise significantly in Kentucky next year.

The White House declined to comment on the race or the prospect of Kynect vanishing. Allies say that’s because it’s distracted by the broader threat of the Supreme Court’s Obamacare ruling.

Yet, the Obama administration has long made clear that Kentucky is the crown jewel of its state-level success stories. The president has delighted in its triumphs, often at his own expense. In 2013, while Healthcare.gov succumbed to technical glitches, Obama recounted the story of a man using Kynect at a county fair.

“He starts looking at the rates and decides he’s going to sign up. And he turns to his friend and said, ‘this is a great deal. This is a lot better than Obamacare,’” Obama said. “I don’t have pride of authorship on this thing. I just want the thing to work.”

And in Kentucky, to the delight of the White House, it did appear to work. More than 400,000 residents have enrolled in Medicaid because of Obamacare, according to state officials. Another 106,000 people had signed up for private insurance on the exchange through April.

But the Bluegrass State is also a reminder that implementation of the law is not the same thing as public buy-in: Beshear was able to enact the exchange and Medicaid expansion through executive order without relying on the legislature; Bevin can use the same method to undo it.

Bevin’s emergence as the Republican nominee was an unlikely reversal of fortunes, just a year after he ran in the Senate GOP primary as a strident, tea party-affiliated conservative against McConnell. His two closest primary competitors, Hal Heiner and James Comer, also ran on dismantling Kynect. But beneath their rhetoric was a much softer approach.

Neither Comer nor Heiner would have eliminated the state-run exchange. “That doesn’t have really any financial effect in this state,” Heiner told POLITICO in a recent interview. Rather, he and Comer focused most of their energy on the surge in Medicaid enrollment enabled by the health law. But on that front, too, neither candidate pledged to outright end the expansion. Heiner said he would’ve modeled a solution on other Republican-led states that offered conservative versions of expansion, like Indiana or Tennessee.

Beshear said any attempts to overhaul or eliminate the Obamacare programs would set the state back. A report his administration recently commissioned from Deloitte — which Republican critics have rejected as spin — suggests the expansion has been a fiscal windfall for the state, worth billions in economic activity and creating more than 10,000 jobs.

“If at any point in the future, we determine that Kentucky can’t afford that, we always have the option to back off. But right now, it is paying for itself,” he said. “If we can make our people healthier, who should be against that? The governor of this state ought to care about his people.”

If Bevin closes Kentucky’s exchange, it would be the first to fold based on an election rather than technical or cost problems. which have been the downfall of exchanges in Nevada, Oregon and Hawaii. Similar woes nearly broke exchanges in Vermont, Maryland and Massachusetts, too. Supporters of the ACA are hopeful that if he is elected, Bevin will back away from the campaign rhetoric once he’s in office, but they’re somewhat resigned to the possibility that the program’s success might not be able to save it from unrelated politics in a red state.

“I think there’d be real remorse about how people who were uninsured before, have now been able to enjoy significant coverage, are now going back to the dark ages in Kentucky,” said Ron Pollack of Families USA.

Unswayed by pronouncement of Kynect success, Bevin stays on message.

“Just having health insurance doesn’t mean you’re going to get health care,” he said.