REPUBLICANS SOLD the American Health Care Act (AHCA), the Obamacare repeal-and-replace plan that the House passed last month, with a number of untruths, chief among them that Obamacare is collapsing and the GOP effort is nothing short of a rescue plan. The Congressional Budget Office, Congress’s official scorekeeper, found Wednesday that the Republicans’ bill is no such thing. Not only would it result in 23 million more people lacking health insurance in a decade, but it would destabilize some states’ individual health-care insurance markets for all but relatively healthy people.

According to the CBO, the current Obamacare system would result in “sufficient demand for insurance by enough people, including people with low health care expenditures, for the market to be stable in most areas.” In contrast, under the House’s alternative, the CBO predicts that about one-sixth of the population would reside “in areas in which the nongroup market would start to become unstable beginning in 2020.”

That is because some states would seek waivers from health-care market rules that would allow healthy people to segregate themselves in their own inexpensive risk pool, leaving sicker people with skyrocketing costs. “People who are less healthy (including those with preexisting or newly acquired medical conditions) would ultimately be unable to purchase comprehensive nongroup health insurance at premiums comparable to those under current law, if they could purchase it at all,” the CBO found.

This is just one of the effects that would lead, overall, to 51 million non-elderly Americans lacking health-care coverage in 2026, rather than the 28 million who would go without under current law. The bill would hit the vulnerable especially hard: “The increase would be disproportionately larger among older people with lower income — particularly people between 50 and 64 years old,” said the CBO.

Some of the biggest losses would come from the AHCA’s $834 billion cut to Medicaid, the state-federal health-care program for the poor and near-poor. The 14 million people leaving Medicaid rolls would have to look for insurance on the individual insurance market. But that market would look very different. Some states, as noted above, would seek waivers that could destabilize their markets. In other states, the picture is only a bit brighter: Smaller subsidies to help people buy insurance and pay out-of-pocket costs, combined with lower-quality plans being sold, would result in fewer people buying individual market coverage. Anyone who fell through the cracks would be at the mercy of whatever safety net their states put in place to catch them.

Instead of contending seriously with this analysis, some Republicans have embraced the argument of last resort, claiming that you can’t trust the experts. It’s true that, because the bill’s effects would depend heavily on how states react, they are particularly hard to assess. But that does not mean the CBO is therefore safely ignored. The experts could, in fact, be underestimating the pain the AHCA would cause. No one, and certainly not the bill’s backers, can produce more credible projections.