The details of the Senate GOP plan are beginning to emerge, although everyone is still pretty confused. But the gist is that if Republicans have the 50 votes necessary to get on the bill, they'll vote on both the replacement plan they've been working on and their partial repeal plan — both of which are expected to fail — and then have to trust McConnell for whatever comes next.

The plan, according to two senior GOP Senate aides:

Take the vote on the motion to proceed, which would begin debate on the House-passed bill. It's unclear whether this has 50 votes. If it doesn't, this is where the plan ends. If the motion to proceed passes, vote on the Better Care Reconciliation Act — the leading replacement plan. Here's where things get murky: Sen. Rob Portman has struck a deal that would add $100 billion to the bill's stabilization fund. It would pair with Sen. Cruz's consumer-freedom amendment, which allows insurers selling ACA-compliant plans to also sell non-compliant plans. But a vote on that agreement would be subject to a 60-vote threshold because it hasn't been analyzed by the Congressional Budget Office. That means it'll fail. Then would come the vote on an updated version of 2015 straight-repeal bill. This is also expected to fail. (The way leadership is structuring the vote procedurally, this would technically be the first amendment voted on — likely as a nod to Sen. Rand Paul — even though BCRA would be on the table first.) If votes on the 2015 bill and BCRA both fail, all votes are to amend the House bill. It's unclear what these votes will be, but Democrats are sure to make Republicans take some painful ones. No one knows what the final bill will be, "because we don't have a product that 50 senators agree to," one of aides said. No one will see a final product before the vote on the motion to proceed tomorrow, unless something is being drafted overnight, the aide added. "This is a leap of faith in [Majority Leader Mitch [McConnell. We have no idea what the final product will be."The second aide added that "the ultimate goal is to get to conference where there would be more time to work out some of the issues and get scores on these items."

But things are in flux. "Everybody is kind of all over the place on what they think they've heard as far as procedure and ordering of amendments," the second aide said. "It's like we all agree that Portman, Cruz, and repeal all get votes, but the process has everybody scratching their heads."