Don Berwick's last job was running Obamacare's implementation at the Department of Health and Human Services, where Republicans berated the former doctor for supporting the British health service.

His next goal: bringing single-payer health care to Massachusetts.

The former Medicare administrator is the only candidate in the Massachusetts governor race running on a single-payer platform. He says he settled on the idea when he was thinking through the different goals he wanted to achieve — slower health care cost growth, better quality care — all seemed most attainable when the government was the one paying everybody's health care costs.

"I began to list the policies I wanted to pursue, and then I came to the payment side...and I started to talk to the people who helped shape Vermont, looked at Vermont, and I just said, 'oh my, there is just one straight shot here, it's going to single-payer,'" Berwick said in an interview Wednesday.

"At that point it was more about thinking about putting it on the table. Now it is the entire table."

Does single-payer help patients?

Berwick was fairly convinced by Vermont's research suggesting that moving to a single-payer system would help reduce costs, because the state would have more power to negotiate lower prices. In our interview, we got to talk a little bit about what a single-payer system would mean for patients: would single-payer stifle innovation, if you didn't have different insurers competing against each other?

This is a particularly important issue for Massachusetts, which is home to huge powerhouses of academic medicine like Massachusetts General and Harvard Brigham-Women's hospitals.

Berwick's view is that a single-payer system would actually be better equipped to handle new innovations in medicine. As the only payer in the game, the government could more easily demand changes from providers who weren't up to snuff.

"A single payer system can become a really powerful force for enhancing competition among providers," Berwick argues. "One reason is that you're doing metrics that are standardized, so you can see what's actually happening. Right now, you can't compare Cigna's beneficiaries to United's."

Berwick cited one example from running Medicare, which is essentially a single-payer system for Americans over 65. When he received a report that over 300,000 beneficiaries were being treated "atypically" with anti-psychotic drugs. Nursing homes seemed to be using drugs typically meant to treat psychiatric conditions to keep patients chemically restrained.

So Berwick called in the leaders of various nursing home groups to Washington and demanded changes in their practices. Speaking on behalf of more than 50 million beneficiaries, he says, gave him more clout.

"I could go to the mat and act protectively," Berwick says. "I was able to tell them, either you fix this, or I will. I don't think there's a single private insurer who would have done that."

Berwick's view is that there can be good management and bad management — both in a single-payer system, and in a private health insurance plan.

"Bad management is bad management," he says. "We have to understand, in either situation, how to keep consumers in focus."