When Bernie Sanders released his single payer plan earlier this year, I expected many of the smart health policy writers on the left to shout “Hallelujah” – at long last, a serious presidential candidate who will give us Medicare-for-all.

To my surprise, most of them said, more or less, “Thanks, but no thanks.” It’s not that they wouldn’t like a single payer plan, in theory. Most would: it’s been a Democratic aspiration for decades. But they recognize it’s not going to happen in the immediate future. Or even in the not-so-immediate future.

Even Sanders himself acknowledged that himself in one of the early debates – back when single payer for him was a defining ideal – before Hillary Clinton elevated it into a policy plank that differentiated the dreamer from the do-er (in her vision at least). As Sanders himself has noted, single payer can’t happen unless or until the whole Washington-Campaign Finance-K Street influence is thoroughly reformed.

But there are other reasons. Not all Democrats want it – either because they think it’s not practical or because they’d prefer to improve Medicare before enlarging it. Or they simply just don’t think single payer is a great idea. Several economists who are quite sympathetic to Sanders’ basic goals say his numbers just don’t add up – he underestimates costs and overestimates savings. Many – as President Obama has said – think single payer would be great if we were creating a health care system from scratch, but we’ve got an employer-based, private-insurance system that’s decades old and even more firmly implanted because of some tax code changes favoring that form of health insurance in the 1950s. Such a change, involving nearly a fifth of the economy and millions of jobs, is extremely disruptive.

For those of you who think the political obstacles are overstated – it’s worth remembering that Democrats couldn’t get anything resembling single payer through Congress when Obama was elected and they had large majority in the House as well as a filibuster-proof majority in the Senate. They couldn’t even get approved a “public option” representing a sliver of single-payer within the ACA exchanges. And their fallback, the coops, had so many restrictions and caveats built in that half have failed and the other half right now aren’t doing so great.

For all the problems that remain in our health care system – cost, access, the millions who are still uninsured – which Sanders diligently has been bringing attention to, it’s sometimes easy to forget how much the ACA did change how the insurance industry operates. Plans must now offer a package of standard essential benefits, they must take everyone, sick and well, old and young. There are limits to profits and administrative spending under MLR (medical loss ratio). These are big, significant changes from the pre-2010 system, however imperfect the system remains – and we all know it remains imperfect indeed.

Below are some of the articles and essays, mostly from progressives, who don’t think Sanders plans add up or don’t think the timing is right. (I haven’t included more conservative writers, but just check National Review, Washington Examiner, etc., they’re easy to find.) I’ve also included some Mother Jones articles that are more supportive, as well as links to the major physician organization that backs single payer. There you will find some columns and articles in favor. I’ve also included an interesting piece by longtime AHCJ member Trudy Lieberman on the failures of the ACA, written several months before Sanders took off.

But before you start reading, here’s one more point that should be made in fairness to Sanders. Clinton keeps saying that Sanders would dismantle the protections of the ACA, CHIP, and Medicaid, undoing the gains and leaving people unprotected. Sanders, who did vote for the Affordable Care Act despite some ambivalence, has said clearly that he wouldn’t take away anything until he had something better to take its place. But Clinton persists in using this talking point. We’ll see if that changes.

• Jonathan Cohn in the Huffington Post: Here’s One Big Problem With The Bernie Sanders Plan For Health Care Utopia; Another Debate Kicks Off With A Sharp Clash Over Health Care.
• James Surowiecki in The New Yorker: The Many Problems with Bernie Sanders’s Health-Care Plan – The New Yorker.
• Harold Pollack in the Journal of Health Policy and Law: Medicare for All –  If It Were Politically Possible – Would Necessarily Replicate the Defects of Our Current System.
• Paul Krugman: Weakened at Bernies and Single Payer Trouble. And here are a batch of New York Times op-ed letters disagreeing with Krugman.
• Kevin Drum at Mother Jones has been more supportive, but notes some questions about the financing: Yet Another Look at BernieCare.
• Trudy Lieberman in Harpers’: Wrong Prescription?
• Physicians for a National Health Program: Doctors group welcomes national debate on ‘Medicare for All’ and other articles of interest.

Contributing editor to Politico Magazine and former health care editor-at-large, Politico, Commonwealth Fund journalist in residence and assistant lecturer at Johns Hopkins Bloomberg School of Public Health.