Senate Republican hopes to overhaul the U.S. health insurance system appear to hinge on the passage of a “skinny” bill that would only repeal a select few provisions in the 2010 health care law.

GOP senators and aides anticipate that several of the other Republican health care proposals expected to be considered by the chamber in the coming days will fail, clearing the way for a package that would likely just repeal the employer and individual mandates and an excise tax on medical device manufacturers.

But even that plan to advance a slimmed-down repeal bill faces difficult odds.

The chamber on Tuesday narrowly approved a motion to proceed to the House-passed bill to repeal and replace the 2010 law, with Vice President Mike Pence breaking a 50-50 tie.

Republican leadership can now bring up for a vote several different proposals intended to, in some way or another, revamp the country’s health care system.

Despite clearing that procedural hurdle, the GOP still faces an uphill battle in rallying the support necessary to pass a final bill out of the chamber. Republican lawmakers are openly doubting that they have the votes necessary to advance either a repeal-only bill or legislation that would both repeal and replace portions of the health care law.

“If this process ends in failure, which seems likely, then let’s return to regular order,” said Sen. John McCain of Arizona, who made a triumphant return to the chamber to cast one of the deciding votes on the motion to proceed after being diagnosed with brain cancer last week.

Senate Majority Leader Mitch McConnell and his top lieutenants, speaking to reporters after the vote, also acknowledged the difficulty facing the conference.

“We’re not out here to spike the football,” the Kentucky Republican said. “We’ll finish at the end of the week, hopefully, with a measure that can either go to the House and either be taken up or go to conference.”

“We cleared the first hurdle, but obviously, there is a lot of work yet to be done,” Senate Republican Conference Chairman John Thune of South Dakota added.

Best path forward

Republicans view a “skinny” repeal bill removing the individual and employer mandates as their best chance at consensus, according to GOP lawmakers and aides.

The strategy, they say, is to pass that measure and go to conference with the House to hash out a broader repeal-and-replace package.

“My personal goal is to make sure that we find something that 50 of us agree on, that we can then pass as a vehicle to get to conference to do a more comprehensive bill,” Senate Majority Whip John Cornyn of Texas told reporters. 

The Senate parliamentarian on Tuesday also dealt yet another blow to Republicans, when she provided guidance that several additional provisions of McConnell’s repeal-and-replace measure — including one that would change the law’s age-rating bands — violate the so-called Byrd Rule. The parliamentarian on Friday said a number of other provisions also violate that rule, which prevents extraneous measures from consideration under the reconciliation process.

Cornyn was unaware if the “skinny” bill would be crafted ahead of time and introduced as an amendment or compiled together on the Senate floor through separate votes.

Other amendments appear destined to fail.

Estimates from the Congressional Budget Office are not expected to be ready for several of the measures likely to be considered in the vote-a-rama, the process under which nearly unlimited amendments can be offered by either Democrats or Republicans.  

That analysis is required in order to determine if the legislation in question complies with the rules governing the fast-track budget reconciliation procedure that Republicans are using to try to advance a bill with only a simple majority of support.

Without the estimate from the nonpartisan budget office, amendments are unlikely to be allowed to pass with only 50 votes and a tie-breaking vote from Pence. 

“I think a 60-vote threshold for the vast majority [of amendments], unless there has already been a CBO score,” Sen. Tim Scott of South Carolina said. 

That means backing from Democrats will be necessary to pass several of the amendments, an unlikely occurrence given the partisan path Republicans chose to pursue for the entire process.

“We’re going to give our members, when such amendments are offered, we’re going to give them a clear choice, side-by-side amendments that address the same issue,” Senate Minority Whip Richard J. Durbin told reporters when asked whether Democrats would support any Republican measures. “Ultimately, we believe it should be a committee process and all of these elements should be included. Let’s wait and see.”

Threshold questions

Among those amendments that will likely need to clear the 60-vote threshold is a proposal from Sens. Bill Cassidy of Louisiana and Lindsey Graham of South Carolina that would essentially give states a bulk amount of money to manage their individual insurance markets.

An amendment from Sen. Ted Cruz of Texas that would allow insurers to offer plans that do not comply with mandates in the current law is also expected to need to clear the higher vote threshold, along with a measure from Sen. Rob Portman of Ohio that would pour more money into the repeal-and-replace bill for Medicaid.

Republicans could look to Senate Budget Chairman Michael B. Enzi of Wyoming to use his own judgement on the more basic provisions for which some version of a CBO estimate may already be available, employing a rarely used authority provided under the Congressional Budget Act.

“It’ll be up to the budget chairman, if he thinks there’s a reasonable basis to calculate the impact and he can go ahead and approve it. But the big bills with all the interacting parts … you need a score for that,” Cornyn said.

McConnell, following Tuesday’s vote on the motion to proceed, introduced as a substitute amendment a repeal bill passed by Congress in 2015 that was vetoed by President Barack Obama. 

But between now and when the chamber considers that language, it is difficult to predict just how many different measures senators will vote on.

“It’s really entirely impossible to predict in a reconciliation debate exactly what amendments will be offered or what amendments will succeed,” McConnell said. “It’s wide open.”

Andrew Siddons and Lindsey McPherson contributed to this report.