Former Medicare chief Don Berwick, who came to symbolize Republican opposition to Obamacare, is backing single-payer in his campaign for the Democratic nomination in the Massachusetts gubernatorial race.

Don Berwick – who, as administrator of the Centers for Medicare and Medicaid Services, oversaw large chunks of the early implementation of the Affordable Care Act – is trying to shake up the health policy world again. He ran CMS from July 2010 to December 2011, and left because Senate Republicans blocked his confirmation to lead the agency permanently. Now, more than two years later, he is a long-shot Democratic candidate for governor of Massachusetts and the heart of his platform is a single-payer health plan.

Vermont is the only other state actively pursuing a single-payer system — long a dream of progressives — and Berwick believes Massachusetts, which did coverage expansion and is trying to contain costs, is ready. Berwick spoke with me and Washington Post health-care reporter Amy Goldstein on Tuesday about his campaign, his vision for state health reform and his assessment of the Affordable Care Act so far. Here's some of our conversation, lightly edited for clarity and brevity.

In the beginning of your campaign, you said you wanted to look at single-payer as an idea. But it seems you've shifted and said, 'We should definitely go for this.'

I realized as I laid out a platform I wanted to have for health-care reform in the state, its delivery reform — the system has to function at a much higher level of quality and much lower cost. I know what that looks like. I spent 30 years of my life working on better care at lower costs, but that involves reconfiguration around completely integrated care, team-based care, putting mental health services in the middle, making sure that prevention is taken very seriously instead of as an afterthought.

As I worked through that plan, payment reform is essential. The legacy system payment reform [in Massachusetts] right now is Chapter 224, which is a voluntary effort to move toward global payments, away from fee-for-service, toward agreed targets for total cost rise that are more modest than we've lived with. I was concerned right at the start about the lack of teeth in Chapter 224. ... The more I thought about it and looked at the data and the Vermont plan, the more I realized that having a single-payer system, Medicare-for-all at the state level, could be a big accelerator to the delivery system redesign that we need.

In Massachusetts, it's the insurance system that's driving delivery system reform with what Blue Cross Blue Shield has been doing with the alternative quality contract. What's your sense of how well that's going?

I credit Blue Cross for what they've done. It was a good move. It's being increasingly embraced in the state, and it's making some dents to the rate of rise [in costs]. But it's not enough. We need a more powerful set of tools for making the health-care delivery system where it needs to be. We're getting back only a fraction of what's available if we're going to change the way care is given. It doesn't address administrative costs fundamentally. It still leaves us with a mixed model, and the amount of change in the delivery system is still very modest. We don't see migration to the completely integrated system that we really need.

The ACA includes programs meant to support delivery system reforms and accelerate those models. What’s your assessment of how that’s performed so far, and how much further do you think it can go?

I’ve always seen it as a learning process. For all of the changes in the ACA — around integrated care, bundled payment, community-based medical homes, community-based care transitions — I've called it an expedition. It's a national expedition with exploring this river up [accountable care organizations], and this one around bundled payment and this one around community-based care transitions. There are some successes and some failures, but some successes. I think if we were to take a deep breath and quell the political obstructionism and the rhetoric, we would know — we do know — so much more than we did before.

Looking back at the ACA rollout issues, is there anything during your time as CMS administrator where you look back and think, "Maybe I should’ve seen this coming," or you didn’t put enough attention on certain areas?

My memory is of everything we did get done. During the time I was there, we issued on-time, on-budget series of regulations that really changed the game. We put prevention benefits in Medicare, we closed the prescription drug doughnut hole, put 3 million kids under their parents’ policies  up to age 26. We were very busy with the early-stage implementation of the Affordable Care Act. That’s what I recall. It was great.

What changes in the ACA would you like to see?

Most of the changes in the ACA I’d like to see are accelerations. Going faster toward getting away from fee-for-service, much more support for integrated delivery systems and backing away from the incentive structure that forces you to do more and more things that don’t help people. I'd accelerate the process toward transparency. I think there are transparency provisions in the ACA that I care a lot about, and I'd have those be much stronger, much more quickly enforced.

There's been some discussion recently about whether the employer mandate is still necessary. Massachusetts had its own employer mandate. Is it needed in the ACA?

In the current multi-payer context, yes. You need to make sure everyone's playing, or you have adverse selection and people left out, or you're burdening just the employee too much. One of the attractions of single-payer is the question goes away.

Does it look like the administration is taking the employer mandate seriously? [It's been delayed twice.]

I don't know. I'm not in touch with the people that are making the decision. If we are going to have an insurance-based system, everyone has to play and be part of the solution. You can't just say, "I'm going to be a bystander." Now, if you want to move away from the employer-based insurance system totally, that’s a different matter. We’re not approaching that. Even the Vermont plan is payroll-taxed based. I guess that’s the way America is configured right now.