This is the web version of VoxCare, a daily newsletter from Vox on the latest twists and turns in America’s health care debate. Like what you’re reading? Sign up to get VoxCare in your inbox here.

The American Health Care Act is inching closer to passage, with conservatives getting on board for an amendment to allow states to opt out of some of Obamacare’s central insurance rules. That was a must-have for the House Freedom Caucus, which has now formally endorsed the bill, because they want to unwind as much of the health care law as possible.

States would be allowed under the plan to waive Obamacare's regulations that require health plans to cover certain benefits and prohibit plans from charging sick people more than healthy people.

But now you have to wonder: How many states would actually choose to roll back these popular insurance protections for their citizens?

And even if they did, the waivers will eventually expire. What happens once the next Democratic president is elected?

vox-mark Sign up for the newsletter VoxCare Get our newsletter in your inbox once a week. Email (required) By signing up, you agree to our Privacy Notice and European users agree to the data transfer policy. For more newsletters, check out our newsletters page Subscribe

Americans with preexisting medical conditions are surely unnerved by even the possibility of returning to the pre-Obamacare market. But there are still these real questions about what the practical consequences of this policy would be.

The amendment does make it quite easy for states to get a waiver. They just have to attest that the waiver will achieve some goal — like lowering premiums — and approval is assumed unless the Department of Health and Human Services stops it.

Which, at least under a Trump administration, doesn’t seem likely.

So states would probably have a green light for now to unwind these provisions, if they wanted to. But would they do it?

Opinions were actually divided among some conservative policy experts I asked on Wednesday. Some certainly might — after all, nearly 20 GOP-led states have refused to expand Medicaid under Obamacare. Opposition to the law runs deep.

"Some may, and many should," Avik Roy, a leading conservative thinker on health care, told me. "Governors who want to see premiums go down should use whatever flexibility they're given to achieve that."

But others were more skeptical that there would be widespread pursuit of these waivers.

"Based on everything I’ve seen and heard, very few will pursue it," Chris Jacobs, a conservative analyst who has worked for House and Senate Republicans, told me. He noted in a blog post on the issue that "exactly zero Republican governors have publicly expressed an interest in applying for a waiver."

"With Republicans occupying literally two-thirds of the nation’s governorships, the silence from state houses seems deafening," he wrote.

Then there is the 10-year limit on the waiver. Beyond that, states would need to reapply. Approval is again presumed, unless HHS steps in.

But 10 years after these waivers could be enacted, we could be living under President Elizabeth Warren’s administration. It’s hard to imagine a Democratic president agreeing to allow states to continue undercutting Obamacare.

Some conservatives already seem well aware of this risk.

"That appears to create a wide opening [for] a future Democratic Secretary of HHS to either deny a waiver outright, or create a litany of new information requirements to kill the waiver," the Washington Examiner's Philip Klein wrote on Wednesday.

I had heard some concerns about this from conservatives when the waiver concept was first floated.

But given the Freedom Caucus’s endorsement, a 10-year waiver must be good enough for them. The whole policy is founded in letting states decide — a tenet of federalism that surely appeals to these small-government firebrands.

But it also leaves open the distinct possibility that this policy conservatives have fought so hard to win would have a limited practical effect.

Chart of the Day

Americans don't want Trump to sabotage Obamacare. This issue will still be live as long as the White House is circumspect about the future of the law's cost-sharing reductions. It's clear from the polling that Trump is playing with fire. Read more from the Kaiser Family Foundation.

Kliff’s Notes

Your daily top health care reads, with research help from Caitlin Davis