With eight hours left of debate in the Senate reconciliation process, it appears all of the Republicans’ chances of repealing (or replacing) Obamacare will come down to a single option: the “skinny repeal.”

Not much is known about the skinny repeal, however. At the end of Wednesday’s debate session, Minority Leader Chuck Schumer blasted Majority Leader Mitch McConnell for keeping the text of the bill secret, and promised that Democrats would offer no further amendments until the secret plan was revealed. What is known about the ace up McConnell’s sleeve is that it would likely eliminate Obamacare’s individual and employer mandates, along with some of its taxes, but the specifics and the broader impacts of such a bill are as of yet unknown.

But Wednesday evening, some of the effects of a bill like the skinny repeal became more clear. Democrats submitted a draft of what they expect in the skinny repeal to the Congressional Budget Office for a score estimate on the deficit, the number of people covered, and premiums. The CBO score found that their proto-skinny repeal would increase the number of uninsured people by 16 million over baseline estimates by 2026, would decrease the projected federal deficit by $142 billion over the same time period, and would increase premiums in the exchanges by 20 percent.

Congressional Budget Office

Caveat emptor: This isn’t a score of the actual skinny repeal deal, but of an approximation of what it’s expected to contain. Based on Senator Rand Paul’s comments, and some other reports from Republicans, the scored amendment would repeal Obamacare’s mandates, repeal its medical-device tax, defund Planned Parenthood, eliminate the Prevention and Public Health Fund, and eliminate Obamacare’s additional commitment to community health centers. At least one of those provisions—defunding Planned Parenthood—has already been shot down under the 50-vote rules by the Senate parliamentarian, so it’s unlikely that provision would show up in a serious reconciliation bill. So it’s already all-but-certain that this won’t be the precise form the actual bill takes.

But that rough estimate is in keeping with previous analyses. The CBO has held that repealing the mandates would result in about 15 million more uninsured people, and would account for the bulk of coverage losses absent major changes to Medicaid. And the CBO and several outside analysts have long held that repealing the individual mandate would raise premiums by somewhere between 10 and 20 percent.

In all, such a move might weaken markets, mostly because poorer people might leave. While Republicans have cast those exits as features of their plan giving people the freedom to choose not to pay for insurance they don’t want, previous CBO reports make clear that much of the coverage losses would come from people whose premiums would jump in such a market. The 20-percent number is an average, but it wouldn’t be applied equally across plans: As healthier, cheaper people leave and make exchange markets sicker, premiums will increase sharply for sicker people.

With these numbers, Democrats have more ammunition to assault the “skinny repeal.” But the score shows just how few Republican goals the strategy would meet as well. As Margot Sanger-Katz writes in The New York Times, “repealing the individual mandate would increase premiums and do nothing about deductibles.” The law would decrease coverage and increase costs, but would dismantle none of the insurance regulations and few of the taxes that Republicans have rallied against for seven years.

A bipartisan group of governors, including Republicans Brian Sandoval of Nevada, Charlie Baker of Massachusetts, John Kasich of Ohio, and Phil Scott of Vermont, wrote a joint letter Wednesday criticizing the skinny repeal along those lines, saying the law is “expected to accelerate health plans leaving the individual market, increase premiums, and result in fewer Americans having access to coverage.”

But the political prospects of the skinny repeal might not rest solely on its own policy merits. It’s widely assumed that such a skinny repeal could simply be a vehicle for getting enough Republican votes to pass a bill, and then getting the bill to a conference committee, where it could be loaded up with more provisions, like a repeal of Obamacare’s Medicaid expansion.

Texas Senator John Cornyn supported that approach Wednesday. “To me, that seems to have a lot of benefits,” he told reporters. “Getting us to conference, where the House has passed a comprehensive bill.”

But whether the skinny repeal is the endgame or a stealthy plot to enact sweeping reforms through procedural maneuvers, after multiple failed votes it does appear to be the only game for Republicans right now.