Last week I worried that Elizabeth Warren had painted herself into a corner by endorsing the Sanders “Medicare for All” plan. It was becoming obvious that she couldn’t stay vague about the details, especially how to pay for it; and some studies, even by center-left think tanks, suggested that any plan along these lines would require large tax hikes on the middle class. So what would she come up with?

Well, the Warren plan is now out. And I’d say that she passed the test. Experts will argue for months whether she’s being too optimistic — whether her cost estimates are too low and her revenue estimates too high, whether we can really do this without middle-class tax hikes. You might say that time will tell, but it probably won’t: Even if Warren becomes president, and Dems take the Senate too, it’s very unlikely that Medicare for All will happen any time soon.

Nonetheless, Warren needed to show that she was working the problem. And she did. She brought in real experts like Donald Berwick, who ran Medicare during the Obama years, and Betsey Stevenson, former chief economist at the Labor Department. And they have produced a serious plan. As I said, experts will argue with the numbers, but this is the real thing — not some left-leaning version of voodoo economics.

How does the Warren plan expand Medicare to cover everyone without raising taxes on the middle class? There are four main components.

First, the Warren team argues that a single-payer system would provide significant savings in overall medical costs — more than other studies are assuming. Some of these would come from bargaining down prices, especially on drugs. Others would come from a reduction in administrative costs.

Are these savings plausible? Well, America does pay incredibly high prices for drugs compared with other countries, and the complexity of our system imposes a huge administrative burden — not just the overhead of insurance companies, but the sheer number of people doctors and hospitals have to employ to deal with multiple insurers. I’ve been puzzled at the reluctance of other studies to credit Medicare for All with big savings on these fronts.

And we should note that even with these assumed cost savings, U.S. health spending per capita would remain far above that of other advanced countries. So there’s a case — not an open-and-shut case, but a reasonable one — for optimism here.

Second — and the cleverest item in the plan — the Warren team would basically require employers who are now offering health insurance to their employees to pay the cost of that insurance to the government instead. Bear in mind that large employers are already required by law (specifically, the Affordable Care Act) to provide insurance. So this would just redirect those funds.

Third, state and local governments currently spend a lot on health care, mainly but not only through their share of Medicaid spending. The Warren plan would require “maintenance of effort,” basically requiring that states continue to spend that money, but on supporting a national plan.

Finally, even with all this there’s a significant budget hole. Warren’s team argues that this can be closed in two ways: some further taxes on corporations and large fortunes, and — an important point — strengthening the IRS, which we know fails to collect large amounts of legally owed taxes, principally from people with high incomes, because Republicans have starved the agency of resources.

Am I enthusiastically endorsing this plan? No. I still think that a public-option-type plan, which lets people buy into Medicare, would have a better chance of actually becoming reality — and may well be where a President Warren actually ends up if she gets to the White House. And the plan’s optimism on costs and revenues could be wrong.

But this is a serious plan that reflects hard thinking. In particular, it’s nothing like the snake oil that passes for policy analysis on the right, whether it’s the continual insistence that tax cuts pay for themselves or Paul Ryan budgets that assumed that discretionary spending could be cut to Calvin Coolidge levels.

So what has Warren achieved here? Realistically, her health care plan is more aspirational than her other plans. Enhanced financial regulation and universal child care are things she might well be able to accomplish if she not only wins, but wins big, next year. Medicare for All, not so much. And may I say, it would serve the public well if these topics — plus climate change! — got more attention in future debates, and health care a bit less.

Warren’s task was, instead, to counter criticism that she was being evasive on a big issue. I think she has met that challenge.

Paul Krugman

Paul Krugman, winner of the Nobel Memorial Prize in Economic Science, is an Op-Ed columnist for The New York Times.