“The truth is that the Republicans are now in a panic,” Bernie Sanders explained Tuesday night, allowing himself a moment of schadenfreude during a CNN Town Hall debate against Ted Cruz over the future of the Affordable Care Act. “Because the American people have caught on that the absolute repeal of Obamacare without improvements to it, without a plan for making it better, would be an absolute disaster.”

Republicans, too, are awakening to the treacherous reality of rewriting the nation’s health-care policy. With public support for universal health care in the United States at an all-time high and President Donald Trump insisting that his inchoate replacement plan will provide “insurance for everyone”, G.O.P. lawmakers are scrambling to craft an Obamacare replacement that won't rattle insurance markets or tank their chances of re-election.

At the heart of the problem for Republicans is a set of challenges and contradictions that may prove intractable. President Trump has made sweeping, public promises that nobody will lose coverage under his plan; that people with pre-existing conditions won’t be denied coverage; and that the A.C.A.’s Medicaid expansion won’t be rolled back—all of which are expensive. As the law currently stands, the Affordable Care Act is funded through taxes levied on insurers, medical device companies, high-income households, and employers with expensive health-care plans—all of which are on the chopping block. Republicans are racking their brains to devise a magic bullet, but health care experts are skeptical that any market-based solution exists.

“How are you going to put a subsidy in place for people buying on insurance exchanges? How are you going to provide states with the Medicaid money that we promised them?” Senate Minority Whip Dick Durbin recently told Axios. “Pull the string and it all starts to unravel.”

Republicans are also reportedly still searching for a mechanism to prevent people with pre-existing conditions from only buying insurance coverage when they get sick. Obamacare relies on the individual mandate and its accompanying tax penalty, both of which are reviled on the right. Politico reports that tensions are rising within the G.O.P. as lawmakers struggle to identify an alternative to the mandate that isn’t at conflict with Republican principles and wouldn’t result in a spike in the uninsured rate. Imposing penalties on people who enroll late is functionally similar to Obamacare’s tax penalty, which Republicans have vowed to throw away. A more popular alternative, referred to as “continuous coverage,” would ensure that anyone who retains coverage can’t lose their insurance or be forced to pay more if their health status changes. Variations of the idea appear in plans put forward by House Speaker Paul Ryan and Rep. Tom Price, Trump’s pick to lead the Health and Human Services Department.

While the intra-party debate continues, many Republicans on Capitol Hill are slowly beginning to acknowledge that the Affordable Care Act may never be completely unwound. First, Republicans dramatically pushed back their timetable for replacing President Obama’s sprawling health care law, settling on a strategy for an immediate, partial repeal followed by a multiyear replacement process. Now, CNN reports, Republicans are quietly beginning to add a third “R” word to their political lexicon: repair.

“I'm for repealing it and starting over, but you can certainly look at the good things that may be part of the law,” Orrin Hatch, the chairman of the Senate Finance Committee, told CNN. “There are some good things that we would put in any bill.” Senate Health Committee Chairman Lamar Alexander also used the word, telling CNN that Congress’s first task would be “repairing the damage that Obamacare has done” before repealing other parts of the law.