On Tuesday, Republican Sen. Lamar Alexander and Democratic Sen. Patty Murray announced—separately—that they had reached a narrow short-term deal to stabilize individual health insurance markets through 2019. The deal, which Alexander and Murray have been negotiating since the end of the summer, would fund the health care subsidies that President Trump abruptly cut off last week.

With Alexander and Murray—the leaders of the Senate health committee—on board, all the compromise has to do now is pass both chambers of a fractured Congress and be signed by a president who, until very recently, frowned upon anything that might “prop up” Obamacare.

How hard could it be?

Trump actually voiced support for the compromise during an unrelated press conference that was underway when news of the deal broke on Twitter.

“The solution will be for about a year or two years, and it’ll get us over this intermediate hump,” Trump told reporters in the Rose Garden.

Trump’s support—if it lasts—could provide crucial cover for Republicans in both chambers, though it’s not clear if the president’s support will be enough to overcome some lingering policy differences between the two parties.

The stickiest point throughout the talks has been over increasing flexibility for states. The Affordable Care Act requires states to meet certain “guardrails” if they are going to apply for a waiver to try something new under the law. The states have to offer “quality health care that is at least as comprehensive and affordable as would be provided absent the waiver” and must provide coverage to the same number of residents, without adding to the federal deficit.

Republicans have insisted on loosening these constraints; Democrats have resisted. The only “guardrail” that the deal loosens is the “affordability” one. Rather than requiring plans be “at least as affordable,” the submitted plans must offer coverage of “comparable” affordability.

Democrats have framed that as a minor concession and one Murray mitigated by inserting additional language to ensure that states couldn’t use it to charge those with pre-existing conditions more. They applauded Murray’s ability to stave off broader changes, like allowing states to loosen “essential health benefit” minimums. Some Democrats even agree with another element of increased state flexibility, which would allow governors to seek waivers without approval from their state legislatures. Delaware Sen. Tom Carper, a self-described “recovering governor,” told me he supported “leaving it up to the governors to make the call.”

Politically, Democrats have been trying to prove to Republicans that they’re willing to work in good faith, and with some give-and-take, to fix Obamacare. Republicans are already plotting another consideration of repeal and replace next year. Democrats want to remind reluctant Republicans like Sens. Lisa Murkowski, John McCain, Shelley Moore Capito, and others that alternatives are out there, and they’re touting this agreement as proof.

Now it just has to be sold to enough Republicans. That will be especially difficult in the House, where conservative lawmakers constantly threaten House Speaker Paul Ryan’s job if he dares cross them. The Freedom Caucus chairman, North Carolina Rep. Mark Meadows, called the agreement a “good start” on Tuesday even if he’s “not sure it goes far enough to lower premiums.” More worrisome, though, were the comments from North Carolina Rep. Mark Walker, chairman of the massive Republican Study Committee, who said Tuesday that “the GOP should focus on repealing & replacing Obamacare, not trying to save it. This bailout is unacceptable.”

Keep in mind that House Republicans hate Senate Republicans—or at least find it politically useful to blame Senate Republicans for their inability to keep their campaign promises. A lot of House Republicans, after they stuck their necks out to pass an Obamacare repeal bill, will resent Senate Republicans for failing to do their part and then having the gall to jam them with a vote on “propping up Obamacare.”

Meanwhile, Democrats are trying to keep the pressure on Republicans by framing Trump’s decision to cut the subsidies as an act of “sabotage” against everyday Americans, for which Republicans will pay an electoral price. House Democratic leader Nancy Pelosi said the Alexander–Murray agreement “undoes some of the sabotage measures President Trump has proposed,” and Senate Minority Leader Chuck Schumer pointed out the bill contains around $100 million in “anti-sabotage provisions,” such as outreach efforts for open enrollment.

The agreement is likely to go one of two ways. Senate Republicans could swallow their concerns and try to move the bill with few changes, and then hope that Trump is able to provide enough cover for Ryan to do the same in the House. Or conservatives in the Senate and House could insist on further deregulation, to which Democrats would never agree, and the process would stall. “Total and complete inaction” is usually the best bet in this Congress. But if Republicans weren’t feeling at least a little bit nervous about soaring premiums heading into 2018, Murray and Alexander may not have ever reached an agreement. Could that angst be enough to move an actual bill through Congress?