Bernie Sanders and Elizabeth Warren crushed last night’s Democratic Party debate. Time and again, they flagged the moderators’ and their opponents’ disingenuous right-wing talking points, and they dismantled claims that bold progressive policies constitute “wish list economics” and “political suicide.” As the moderates and naysayers stammered and obfuscated, Sanders and Warren worked confidently and gracefully as a team, and that team clearly came out on top.

But Bernie Sanders won an additional prize. Medicare for All, his signature policy proposal for going on four years, was the first and most heated topic of debate. Warren deftly assisted him in deflecting attacks. But make no mistake: the fact that it was discussed at all is owed primarily to Sanders.

Sanders has publicly supported some degree of decommodified health care for four decades. In the ’70s, he called for fully socialized medicine. In the ’80s, he said, “We have a crisis situation. We are one of two nations in the industrialized world that does not have a national health-care system.” In the early ’90s, he brought his first single-payer bill to Congress, saying, “Our system is not in need of band-aids or patchwork or such concepts as managed competition. We are in need of a new system. The American people believe that health care must be a right of all citizens and not just the privilege of the wealthy.”

And last night, he said, “We have a dysfunctional health-care system: 87 million uninsured or underinsured, 500,000 Americans every year going bankrupt because of medical bills, 30,000 people dying while the health-care industry makes tens of billions of dollars in profit.” He added, “Health care is a human right, not a privilege. I believe that, I will fight for that.” Sanders is nothing if not consistent.

Between Sanders’s earliest and his most recent advocacy of single-payer health care, the main change is how many people are taking the idea seriously — including those who are seriously scared of it, and who are parroting insurance-industry talking points to suppress support for it.

In 2016, Hillary Clinton waved the idea away, saying it would “never, ever come to pass.” Now Democratic moderates in Clinton’s mold aren’t so sure, and they’re casting about for new arguments. One offered by several candidates last night was that Medicare for All “rips away health care” and “kicks half of America off their current insurance” — as though Americans wouldn’t relish the opportunity to pay less for more comprehensive coverage on the new universal insurance plan created by Medicare for All.

Another was, bizarrely enough, that union members would lose their hard-won private health insurance. Sanders responded that, with health care guaranteed and not dependent on employers at all, unions could fight for higher wages instead.

Progressive unions, state and national single-payer coalitions, and activists who include nurses, doctors, and patients have all worked tirelessly to get us to the point where we are now, with Medicare for All dominating a debate among candidates seeking the nomination of a major political party. But there’s no question that their efforts were catapulted into the spotlight by Bernie Sanders’s 2016 presidential campaign and his 2017 Medicare for All legislation.

The same can’t be said for Warren, who fully boarded the Medicare for All train just this year. She ran interference like a pro during last night’s debate, but she played a negligible role in popularizing the policy. In a 2008 paper, she acknowledged that single-payer would be a preferable system but claimed it was “politically unacceptable.” It took a full decade for Warren to support single-payer publicly — after Sanders himself had made it politically acceptable.

As recently as last month, Jacobin was still calling on her to go all in on Medicare for All. She finally did . . . at the debate immediately preceding this one.

Warren is a confident and effective debater, and proponents of Medicare for All are lucky to have her on our side. But the debate held special significance for Sanders. He’s been purposefully driving the nation toward a reckoning like this for decades. On the stage last night, others played their instruments, some badly and some virtuosically. But it was Sanders who composed the music.