“If you’re on the left, you have to have something on health care to say at town halls,” said David Blumenthal, president of the Commonwealth Fund. “So you say this and move on. That’s part of the motivation.”

Dr. Carol Paris, the president of Physicians for a National Health Program, an advocacy group, said she has fielded a number of calls from candidates asking for tutorials on Medicare for all.

“I’m heartened, but not persuaded” that all the high-profile talk will result in any action, she said. She worries about what she called “faux ‘Medicare for all’ plans” that don’t live up to the mantra.

Polling highlights health care as a top voter concern, and pressure is building for politicians to take meaningful action that could redress the pain caused by personal health care costs that continue to rise faster than inflation.

Maybe that action would be negotiating lower drug prices or fixing flaws in the insurance system that allow for surprise medical bills and high out-of-pocket costs. Republican candidates mostly continue to bad-mouth “Obamacare” as the root of all problems in American health care (of course, it’s not), and some still push to repeal it. They tend to offer only vague assurances that, for example, they will guarantee that people with pre-existing conditions can find affordable insurance — proposals that do not withstand expert scrutiny.

But more and more voters seem to think the country needs more radical change.

In polling this year, 51 percent of Americans and 74 percent of Democrats said they support a single-payer plan. Surveys suggest growing enthusiasm among doctors, too, with more than half in favor.

Yet experts suggest voter support may not withstand warnings of tax increases or changes to employer-sponsored insurance. A 2017 poll from the Kaiser Family Foundation found that support for Medicare for all dropped when respondents were told that their taxes might increase or that the government might get “too much control over health care” — a common Republican talking point.