A week ago I worried about the Sanders health plan; it looked as if he was low-balling costs in an effort to obscure how hard making such a plan would be, and how many currently well-insured people would end up being losers. I wrote that his plan

both promises more comprehensive coverage than Medicare or for that matter single-payer systems in other countries, and assumes huge cost savings that are at best unlikely given that kind of generosity. This lets Sanders claim that he could make it work with much lower middle-class taxes than would probably be needed in practice. To be harsh but accurate: the Sanders health plan looks a little bit like a standard Republican tax-cut plan, which relies on fantasies about huge supply-side effects to make the numbers supposedly add up. Only a little bit: after all, this is a plan seeking to provide health care, not lavish windfalls on the rich — and single-payer really does save money, whereas there’s no evidence that tax cuts deliver growth. Still, it’s not the kind of brave truth-telling the Sanders campaign pitch might have led you to expect.

Now Kenneth Thorpe, a health policy expert (and a long-term supporter of health reform who believes that single payer would be a good thing if politically feasible) has tried to crunch the numbers, and it really doesn’t look good. Thorpe estimates that the plan would actually require about twice as much new revenue as Sanders claims.

The Sanders campaign is calling this a “hatchet job”; but as Jonathan Cohn says, Thorpe’s assumptions

are broadly consistent with what most health policy experts believe.

Or as Ezra Klein puts it,

the gap between Thorpe and Sanders is the gap between an economist who is optimistic that single-payer can save some money and a campaign optimistic that it can save a huge amount of money.

And it’s not good to see the campaign basically responding to questions about its numbers by attacking the motives of someone who should be on their side.