It is little less than astonishing that Vermont Senator Bernie Sanders—a politician who, not long ago, was widely branded as almost irrelevant, a marginal gadfly from the left—secured a virtual tie with establishment favorite Hillary Clinton in the Iowa Democratic primary. There is no longer any question that
 the Sanders movement—led not so much by the candidate but by the thousands of young people who first turned out for his rallies and are now turning out to vote—is transforming the Democratic race. Indeed, Clinton eked out a razor-thin victory in Iowa because she veered left and finished her campaign with calls for wage hikes to address income inequality and new taxes on the rich—what The Des Moines Register referred to as “populist fire.” But the result gave Sanders, the democratic socialist from the Green Mountain State, a chance to declare: “I think the people of Iowa have sent a very profound message to the political establishment, to the economic establishment and, by the way, to the media establishment.”

When Sanders flew into the first-primary state of New Hampshire the morning after the Iowa caucuses, his supporters greeted him in the name of a political revolution that suddenly seemed very real. Clinton recognizes this: After her bumbling attempts to assail Sanders for his support of single-payer healthcare and progressive tax policies failed to slow the insurgent challenge, Clinton retooled her campaign, infusing it with a “fighting for you” populist rhetoric and declaring, on caucus night, that she was part of “the long line of American reformers who make up our minds that the status quo is not good enough.”

Clinton still has plenty of front-runner advantages, as well as an appeal to core Democratic constituencies that’s likely to give her the upper hand in the post–New Hampshire contest for South Carolina and the bigger states that vote in March. But the crowd-funded Sanders campaign, which has now attracted more than 3 million donations and an ever-expanding cadre of volunteers, can legitimately claim that “the inevitable candidate doesn’t look quite so inevitable.”

The political and media establishment that Sanders mentioned to the caucus-night crowd in Des Moines needs to adjust to that reality. Democratic National Committee chair Debbie Wasserman Schultz, Congressional leaders, and party leaders in the states must not only recognize the changing dynamic of this race; they must accept the need for many more debates. Former Maryland governor Martin O’Malley, who dropped out of the Democratic contest after finishing far behind in Iowa, had objected most loudly to the ridiculously constrained debate schedule, which obscured the candidates from the public by having them spar mostly on weekends or holidays. The party is coming to accept that O’Malley was right. Debates do not merely frame the issues; they force candidates to strengthen their messages, to recognize what works and what doesn’t. Ultimately, debates make the eventual nominees better. They also provide an alternative to an electoral era dominated by super-PAC attack ads, which are defining an increasingly ugly Republican contest.

On the eve of the Iowa vote, after MSNBC and the New Hampshire Union Leader proposed an unsanctioned debate, Clinton and O’Malley said they were on board. Sanders upped the ante by proposing new debates in March, April, and May. After Iowans confirmed that this is a serious contest, the DNC announced plans for three new debates, beginning on March 6 in Flint, Michigan, where a lead-poisoning crisis has exposed the bankruptcy of austerity governance. As the choice of Flint illustrates, debates can and must expand the range of discussion. They can, as well, go deeper on the issues of income inequality, mass incarceration, and US foreign policy.

Clinton and Sanders should guard the quality of the discourse by rejecting the pressure to “go negative” with attack ads that will only harm the eventual nominee. The Democrats have been given an opportunity to engage in the “contest of ideas” that Clinton proposes, and in the broader dialogue that Sanders says is needed to shape the future of our politics and our economy. The candidates and the party should seize the opportunity, recognizing that this is not just the debate that Democrats want. It is also the debate that Americans will embrace, as a refreshing alternative to the cruel and all-too-usual contest of nonstarter “ideas” in which the Republicans have trapped themselves.