If “moderates” like Dean Heller go along with Trumpcare, they may have to explain why coverage losses by many millions of Americans due to Medicaid cuts are suddenly not so bad after all. Photo: Bill Clark/CQ-Roll Call,Inc.

As the dust settles from Thursday’s release of a revised draft of the Better Care Reconciliation Act, the Senate’s version of Trumpcare, Mitch McConnell’s challenge in getting this unpopular bill across the line is clear. According to just about everybody, he’s lost two Republican senators, Rand Paul and Susan Collins. The big concessions he’s made to the right by accepting Ted Cruz’s amendment to let insurers offer stripped-down health plans, and by holding the line on massive Medicaid cuts, has probably won over all the conservatives other than Paul. So now he has to win the rest of the “moderates,” most of whom are unhappy with Medicaid cuts. If you believe the scuttlebutt, Lisa Murkowski of Alaska has been “bought” with a small Medicaid amendment that benefits Alaska almost exclusively, and with a Trump administration waiver that could help the state stabilize its troubled individual insurance market. As my colleague Jonathan Chait explains, Republicans are sounding confident that they can “buy” the remaining “moderates,” with the toughest case being Dean Heller of Nevada.

But for Heller, along with other holdouts like Rob Portman and Shelley Moore Capito, there’s at least one big hurdle to overcome before capitulation to McConnell becomes a realistic option: the Congressional Budget Office “scoring” of the revised bill (assessing its impact on health-insurance coverage, premiums, and the federal budget), expected to arrive on Monday.

There is a lot of confusion surrounding that “score” before it is released. Most important, it is unclear whether CBO will even attempt to assess the Cruz amendment, a moving target at the time the bill was sent to the green eyeshades. “Scoring” this proposal, if that happens, could go in any number of directions, depending on how seriously CBO takes its sponsors’ claims that millions of younger and healthier people will leap onto the cheaper, skimpier plans it authorizes, and its critics’ claims that it will lead to insanely high premium increases for the older and sicker people left in Obamacare plans.

There’s even talk that McConnell will ask HHS or the president’s Office of Management and Budget to offer a “score” of the Cruz amendment, which would be sure to come back adorned with rainbows and unicorns.

Aside from the Cruz amendment, CBO will have to weigh the impact of the new money the revised bill invests in tax-preferred health-savings accounts, that conservative policy fetish that mostly helps prosperous people pay out-of-pocket expenses. And as in early iterations of the legislation, the agency will have to guess what states will do with the various optional waivers and pots of money intended to help them deal with the bill’s baleful effects.

But it is important to understand that most of the mystery and controversy about the CBO “score” involves BCRA’s impact on the individual insurance markets. In the “score” for the original BCRA, of the 22 million Americans projected to lose health insurance if the legislation were enacted, 15 million would be attributable to the bill’s Medicaid cuts. And those were substantially left in place in the revised version.

So for senators who claim to care about the number of new uninsured the bill would create, the CBO assessment will likely come in somewhere between the 15 million the Medicaid cuts alone might cause, and the 22 million in the initial “score” — unless CBO does assess the Cruz amendment and concludes it will hammer people with preexisting conditions, which could drive the number of uninsured up well beyond 22 million.

For the GOP “moderates,” the question will become: Exactly how many millions of people losing health insurance is acceptable? Dean Heller has said he cannot vote for a bill that will cause “tens of millions” to lose coverage. Does that mean 15 million is okay? How about 19 million? If Heller is, indeed, waiting for an offer from McConnell he can’t refuse, then he’d better prepare an answer to that question which he can square with his earlier comments.

On Thursday Vox’s Tara Golshan tried to corner Republican senators with precisely the question of what would represent a “good score” from CBO, and mostly encountered evasions, with some questioning CBO’s accuracy. There is little doubt a “bad score” like the earlier one will generate even more attacks on CBO from conservatives who would just as soon blow up the nonpartisan entity and blatantly cook the books. If “moderates” join in the CBO-bashing fun, McConnell will probably get his 50 votes.