Senate Republicans scored a major breakthrough on health care reform Tuesday after voting to being formal debate on repeal-and-replace legislation. But by Wednesday morning, that breakthrough seemed increasingly illusory.

Lawmakers were confronted with dual, equally problematic political realities: there remains no widespread agreement on final legislation, and the bill with seemingly the best chance of passage faces stiff opposition in the House.

The common thread underlying these two hurdles is that Senate GOP leaders must still find 50 votes in favor of a yet-to-be-crafted bill. If successful, they then either have to convince the House to pass the measure or join House members in a congressional conference committee to hash out their differences. Whatever legislation that committee produces would then be sent back to the House and the Senate for one more round of voting after which—assuming passage—it would be sent to President Donald Trump’s desk.

These are the paths to repealing and replacing Obamacare. Neither is easily traversable.

The most likely proposal to get 50 votes in the Senate, Republican aides told The Daily Beast, is a so-called  “skinny repeal.” It would undo the employer and individual mandates in Obamacare, in addition to the taxes on medical device manufacturers. It would also leave in place Obamacare’s Medicaid expansion, and according to the Congressional Budget Office, 16 million more Americans would be uninsured under the plan by 2021. Premiums would also rise by 20 percent, a Senate Democratic aide said.

So far, both moderate and conservative senators have signalled a willingness to consider skinny repeal, though others remain skeptical or undecided. But the House is an entirely different matter. In interviews with The Daily Beast, conservatives there say the idea is dead on arrival.

“It’s nowhere near repeal. I mean, even the repeal bill isn’t repeal because all the regulations stay in place,” Rep. Dave Brat (R-VA), an outspoken member of the hardline conservative House Freedom Caucus, told The Daily Beast. “People need to get out their Webster’s dictionary and look up the word repeal—and then see if your representative is staying true to their word.”

He wasn’t finished.

“I mean, what’s a skinny bill?” Brat added. “So we’re talking about controlling one-fifth of a $20 trillion economy. And our new creative idea is a skinny bill. So this is the Fatal Conceit up in the bubble that you can dictate one-fifth of the economy with clever phrases… It’s bizarre.”

Rep. Mark Meadows (R-N.C.), the chairman of the House Freedom Caucus, echoed Brat, telling reporters that there is “zero” chance the House would pass the scaled-back repeal.

“We can’t wait for seven years and seven months, and the best that we can send to the president is what he could’ve done almost by executive order,” Meadows said. “My constituents wouldn’t be okay with that. And I don’t think the majority of our constituency for the Republicans would be okay with that.”

The House Freedom Caucus has scuttled health care bills in the past. And if it follows through on threats to reject a Senate-passed skinny repeal plan, then the two chambers will be forced to negotiate. At that point, it’s not entirely clear what Republicans leaders could do to placate majorities in their respective chambers.

On Wednesday, the Senate resoundingly rejected two possible approaches: a procedural vote on Majority Leader Mitch McConnell’s repeal-and-replace measure, as well as a bill that would repeal the law and give a two-year window for lawmakers to come up with a replacement.

Though both measures had been widely expected to fail, their defeat underscored how narrow

the avenues for success currently are for Republicans should they go to conference. But that appears to be exactly where they are heading. Sen. Bob Corker (R-TN), on Wednesday, said that the skinny repeal bill was a “forcing mechanism” to enter a conference committee.

Other lawmakers hid the ball a bit better. Senate Majority Whip John Cornyn (R-TX) pitched skinny repeal as a platonic end product, saying that there are “a lot of benefits” to such an approach. But getting at least 50 Republicans on board for a scaled-back repeal might be a tall order. Sen. Lindsey Graham (R-S.C.) didn’t seem convinced, calling it a “punt.” More moderate members were noncommittal on Wednesday.

One member who said he would support skinny repeal, Sen. Rand Paul (R-KY), said on Wednesday he would oppose sending a bill to conference committee for fear that moderate members would add funds to the final product. (Paul had opposed skinny repeal in 2015, saying it didn’t go far enough to dismantle Obamacare.)

Brat, by contrast, said that if the choice came down to accepting a scaled-back repeal or leaving Obamacare in place, he could very well side with the latter.

“Is it better than doing nothing and keeping Obamacare which is failing? I don’t know,” he said. “Intuitively, I would say doing something is better than doing nothing. But that may not be the case. … If you implement that, what’s left standing? I mean, the whole thing could collapse just like Obamacare.”

And so, the party finds itself inching toward a crossroads: wary of bringing a bill to conference, but uncertain if there is another path forward.