Sen. Bernie Sanders (I-VT) took the stage at George Washington University Wednesday to reclaim an idea he’s made central to Democrats’ health care debate: Medicare-for-all.

Since Sanders brought Medicare-for-all into the mainstream in his 2016 presidential election, it has been embraced by progressives both as an aspirational end goal, and as tangible policy. It’s also been panned, by Democrats and Republicans who say it would be too expensive, too government-controlled, and too difficult to accomplish. The proposal has been attacked by other 2020 presidential candidates as well: This week, former Vice President Joe Biden adopted a misleading conservative talking point that under Medicare-for-all, “all the Medicare you have is gone.”

On Wednesday, Sanders, mounting his second presidential campaign centered on progressive policies, can truthfully say Medicare-for-all is popular. But Medicare-for-all is no longer just Sanders’s original policy directive for government-run single-payer insurance.

It has been redefined by others: It has become Medicare for America, a universal Medicare expansion program; and has been reconfigured into Choose Medicare Act and Medicare X, both of which allow Americans to buy into Medicare. The most blatant appropriation of Sanders’s policy vision has probably come from South Bend, Indiana, Mayor Pete Buttigieg, who pitches “Medicare for all who want it” — endorsing a public option.

Seven months from the Iowa caucuses, Sanders, who is among the top five Democratic candidates in the presidential election, is having to clarify just what he means by Medicare-for-all, and what his plan entails. Unlike his competitors Biden and Sen. Kamala Harris (D-CA), he doesn’t believe private health insurance should have a role in the American system. He’s tired of the back and forth about incremental change.

And fundamentally, Sanders challenges the leading technocratic approach to health care by posing a basic question about a moral problem: Can a health care system in which private insurance plays a significant role incentivize giving sick people care? Sanders says no.

“The debate we are currently having in this campaign and all over this country has nothing to do with health care but has everything to do with the greed and profits of the health care industry,” Sanders said Wednesday.

Medicare-for-all has gotten confused

In its growing popularity, Medicare-for-all, the way Sanders first proposed it, has become confused. Sanders proposal was — and is — one that would almost entirely eliminate private insurance and over a transition period move every American onto a single national government insurance plan. Sanders is explicit about that fact.

But some of Sanders’s fellow presidential candidates who sponsored that proposal, like Harris and Sen. Cory Booker (D-NY), are less steadfast about the idea. Harris, for example, has gone back and forth on the question of private insurance. In the Democratic debate she said she supported abolishing private health insurance in a group question, but later clarified she misunderstood the question and said she did not support it.

Voters also seem to be somewhat confused about the issue. Poll after poll from the Kaiser Family Foundation tracking voters’ perceptions of Medicare-for-all has illuminated that the American people are not clear on what the term means.

The good news for Sanders is that the Kaiser Family Foundation found 56 percent of the public favors “a national health plan, sometimes called Medicare-for-all, where all Americans would get their insurance from a single government plan.” But there’s a lack of clarity about what would happen to private insurance.

When told directly that Medicare-for-all would end private insurance, larger margins support more incremental steps toward a government-run program, like lowering the eligibility age for Medicare.

And notably, a June poll found that many Americans don’t realize just how dramatically single-payer would change how they get health care. For example, 69 percent said they thought people would continue to pay deductibles and co-pays under Medicare-for-all, something Sanders emphasized Wednesday would not be the case.

It should be said that should Sanders become president, making Medicare-for-all a reality will not be remotely easy. As Vox has reported, passing the legislation would likely mean fundamentally changing the Senate’s rules — and even then, there may not be the political support to get the plan through Congress.

Sanders, however, maintains that a popular program like Medicare will continue to be popular if expanded. And he’s clear about how his ideas would impact the private insurance industry. In fact, the crux of his argument for Medicare-for-all is getting rid of the private health care industry’s influence.

A speech about fighting the health care industry

Sanders’s speech ended with a call to his fellow Democratic presidential candidates that summed up what Medicare-for-all is about.

“I am calling on every Democratic candidate in this primary in rejecting money from the insurance and drug companies,” Sanders said. The pledge, which his campaign announced Wednesday, bars donations over $200 from health insurance or pharmaceutical company PACs, lobbyists, or executives.

According to an ABC report, Sanders himself has received several donations that under the pledge would have to be returned. His campaign has said they would be “glad to donate the three donations worth $2700 out of nearly $40 million received since launch,” ABC reported.

The pledge, and Sanders’s focus on the influence of the private health care industry, emphasizes that disruption of the health care system is the point of Medicare-for-all.

“The fight against Medicare-for-all today is not a new development,” Sanders said. “If we are going to break the stranglehold of corporate interests over the health care needs of the American people, we have got to confront a Washington culture that is corrupt, that puts profits before people.”

In other words, he believes, fundamentally, that a health care system reliant on private businesses that have to meet a bottom line cannot truly be invested in providing care to the sick.