As a ritual of modern politics, the cable-news “town hall” is often a slog: curated Americans in tidy rows and their Sunday best; nervous questions; politicians on stools, nodding, and rising to pivot to homilies.

After a few minutes of CNN’s town hall with students and parents from Marjory Stoneman Douglas High School, it was clear that, this time, the formula was off—in a powerful, revealing way. Fred Guttenberg, a father whose fourteen-year-old daughter, Jaime, was one of seventeen people shot to death last Wednesday, fixed his gaze on one of his two U.S. senators, Marco Rubio—a Republican with an A-plus rating from the National Rifle Association. Guttenberg said that Rubio’s comments about the shooting “and those of your President this week have been pathetically weak.” The audience erupted in furious agreement—an angry, standing ovation. Rubio—ashen, unmanned—had no response.

Guttenberg continued, “So you and I are now eye to eye. Because I want to like you. Look at me and tell me. Guns were the factor in the hunting of our kids in this school this week. And look at me and tell me you accept it and you will work with us to do something about guns.”

Rubio might not have shown up at all. Florida’s governor, Rick Scott, did not, and he was mocked several times during the event for not having the courage to attend. (Chris W. Cox, a lobbyist for the N.R.A., has said of Scott, “Rick has signed more pro-gun bills into law in one term than any other governor in Florida history.”) For his part, Rubio—whom the N.R.A. applauds, on its Web site, for opposing “the Obama administration’s efforts to ban firearms, ammunition and magazines, as well as efforts to create a so-called ‘universal’ background check system”—probably figured that he could ease his way around the awkward moments, much as he does on the campaign trail.

He was wrong. While Guttenberg stood waiting, blinking back at him, Rubio responded that the problem “cannot be solved by gun laws alone,” which is the kind of dodge that he and his colleagues routinely make in Washington. It is a phrase that carries the suggestion that, somehow, the question is too simple, too idealistic to be taken seriously. In Washington, where I live and work, reporters ask follow-up questions, of course, but the mood is often decorous and formulaic. This time, Rubio was encircled and out of his usual environment. The crowd jeered him. It whistled. Eventually, Rubio responded that he would support laws raising the minimum age for buying a rifle and banning bump stocks, and said that he was open to discussing limiting large-capacity magazines. He also expressed support for so-called gun-violence restraining orders, a measure popular among gun-control advocates. In the politics of guns, it was a remarkable shift of position—but only if he actually follows through on those commitments.

A few minutes later, a seventeen-year-old junior named Cameron Kasky, one of the founders of the #NeverAgain movement, which is pushing for gun-control reforms, approached Rubio and the other two politicians on the stage, Congressman Ted Deutch and Senator Bill Nelson, both Democrats. He asked Rubio, “Would you refuse to accept donations from the National Rifle Association in the future?”

Further Reading New Yorker writers respond to the Parkland school shooting.

Rubio, hesitating, settled, eventually, on the idea that he would continue to accept N.R.A. funds because, he said, “people buy into my agenda, and I do support the Second Amendment.” The crowd booed. He added, “I will always accept the help of anyone who agrees with my agenda”—a comment so bland and euphemistic that it only dramatized the corrupt aroma surrounding money, guns, and politics. Under stress, Rubio tends to repeat himself, and he cycled through his talking point—“people buy into my agenda”—in a way that was reminiscent of his downfall in the 2016 Presidential race, when Chris Christie mocked him and his repetitive platitudes onstage, effectively ending Rubio’s campaign.

As a moment in American politics, the pummelling of Rubio felt like an expression of collective rage at the falseness of so much that happens in Washington: the pivot, the dodge, the pallid follow-up question. Authenticity has rarely been more sought after in our public life—and, at once, so elusive. Accountability—the knowledge that the men and women we elect will act, foremost, in our interest and not that of their donors—has become a civic myth. Until a week ago, the students and parents of Marjory Stoneman Douglas High School never intended to be part of politics in this way, so they reject its pieties and rhythms. In several minutes on a weeknight, they laid bare Rubio’s central political flaw—inauthenticity—more vividly than I ever could in a magazine profile.

It was easy to watch the town hall and wonder if this will be an inflection point in America’s broken politics regarding guns—a moment when the force of money and political organization will actually be overwhelmed by the public desire to end the slaughter in American schools. But it is naïve to assume that it will necessarily be different this time; those choices are ahead, not behind. A genuine clash over the politics of guns—a challenge from the public to the men and women who serve in their name—might have gained new clarity on live television. But, for the moment to matter to history, that urgency will need to endure long after the cameras have been turned off.