The most important question in the first Presidential debate between Donald Trump and Hillary Clinton should have been an easy one, but Trump had to be asked twice. Photograph by Evan Vucci / AP

The most important question in Monday night’s debate was one that Lester Holt, the moderator, had to ask Donald Trump twice. Trump needed the extra prodding even though the question—“One of you will not win this election. . . . Are you willing to accept the outcome as the will of the voters?”—was one of basic civics and civility. It was also one that he’d just heard Hillary Clinton nail.

“Well, I support our democracy,” Clinton had said. “And sometimes you win, sometimes you lose.” That last phrase was a nod to a quality many of her supporters see in her: the maturity that comes from deciding that a day that may have gone badly for you is not the day you give up. Clinton continued, “But I certainly will support the outcome of this election. And I know Donald’s trying very hard to plant doubts about it, but I hope the people out there understand: this election’s really up to you. It’s not about us so much as it is about you and your families and the kind of country and future you want.” As she spoke, Trump, on the split screen, tilted his head, with pursed lips and a tight nod. He may have wanted to give the impression of a man skeptically sizing up Clinton’s patriotism, but one suspected that he was just mulling the damage Clinton had done to him in the exchange a moment before, in which she quoted Alicia Machado, a former Miss Universe, who has said that Trump called her “Miss Piggy” and “Miss Housekeeping” when she gained weight after the pageant. (The Machado story would become even more baroque in the days that followed.)

In either case, when Trump started speaking, it was as if the greatest puzzle he saw was not how the election results would be received but that certain people had the temerity to vote at all.

“People are pouring into our country,” he said. “The other day, we were deporting eight hundred people. And perhaps they passed the wrong button, they pressed the wrong button—or perhaps, worse than that, it was corruption—but these people that we were going to deport for good reason ended up becoming citizens.” At that, he paused and, shaking his index finger, repeated, “Ended up becoming citizens_._” What was on display here was not just Trump’s lack of discipline—some compulsion to talk about immigrants as if they were destructive infiltrators. The button Trump himself was pushing, for many in his base, was the one that activated conspiracy theories postulating that the main reason Democrats respect immigrant rights is because Democrats want to import pliable voters. Often enough, what sounds like a simple Trumpian non sequitur is something worse: a call to paranoid arms. As Trump began to ramble about the numbers—“And now it turns out it might be eighteen hundred, and they don’t even know”—Holt broke in, and asked the question again. Would Trump accept the results?

“Look, here’s the story. I want to make America great again,” Trump said. “I’m going to be able to do it. I don’t believe Hillary will.” Then, finally, “The answer is, if she wins, I will absolutely support her.”

Why was that, a basic recitation of the workings of the American electoral process, so hard to wring out of him? Holt’s question didn’t come out of nowhere. As Clinton said, Trump has tried very, very hard to plant doubts about the fairness of the election. He has, in rally after rally, suggested that it might be stolen from him in ways both visible and hidden. He asks crowds why Clinton was allowed to run, and says that he guesses she is now the puppet of the President and whoever else got to the F.B.I. and kept her out of jail. He rails about the machinations of power-hungry billionaires, as if referring not to the text in a teleprompter but to a mirror image of himself. The media, he tells his supporters, is helping Hillary by lying about him. He yells, “End the Clinton corruption!”; the crowd responds with a chorus of “Lock her up!” “Cheating” and “rigging” are terms that he has used; so is ”Second Amendment people.” And he tells his supporters, as he did in Iowa on Wednesday, that a Democratic victory might mean that sections of the Constitution will be thrown out with impunity and that there will be no more fair elections: “We’re never going to have another shot—this is it. The tables will turn and then it’s over.” He added, “Remember—follow the money.” Trump, who spent years impugning the legitimacy of the first African-American President, has seemed to be getting ready to attack the legitimacy of the Presidential election itself—unless he wins, that is.

As with so much of the ugliness during this election season, that line of thinking did not originate with Trump but with the Republican establishment, which has spent years pushing the myth of voter fraud as an excuse for coming up with ways to make it harder for minorities and poor people to cast their ballots—stringent voter-I.D. laws, fewer polling stations, a shorter voting window. As has frequently been observed in this campaign, Trump shouts where others whisper, but the message is the same. The volume accentuates the atmosphere of crisis and alarm; the message is of a country being stolen away. This is one of the many reasons a demagogue is dangerous and a sensible, grounding question like the one Holt posed is so valuable. Trump might not stick to his answer, but, in terms of introducing at least a whiff of sanity to this electoral affair, having it on the record is a start. And it should serve notice to Republican leaders, such as Paul Ryan, about the choices they might have to make after the election. Trump can do a great deal of damage to the polity even if he loses, and the G.O.P. will have to decide whether to abet him.

There is another, more subtle sense in which the question might have been a good corrective for the Clinton campaign, too. Her team has, in its own, less flagrant way, flirted with conspiracy theories, suggesting that legitimate concerns about Trump’s ideological affinity for Russian President Vladimir Putin and about the intrusions of foreign hackers raise the possibility of election-invalidating plots. Progressives, too, have been faced with a certain temptation to treat this election, and their opponent, as different from any other in American history, ever. (In truth, we have had rougher times in our country.) The risk, if that fear escalates, is that it will also be seen as a reason to cut corners or give up on progressive values, such as a skeptical, aggressive press. Trump can make anyone stepping into the political arena feel dizzy; the answer is not to spin ever more wildly. If she loses, as I wrote earlier this week, it will be all the more important to hear her speak, calmly, in a way that reaffirms the strength of our institutions. And doing so now is not a fool’s errand. Clinton, in quoting Michelle Obama’s prescription, in her Convention speech, for how to respond to slurs like birtherism—“When they go low, we go high”—acknowledged this. (The former governor and Party chair Howard Dean’s suggestion, during and immediately after the debate, that Trump was displaying the symptoms of cocaine abuse, did not quite live up to that ideal.) Fixating on the idea of a Russian plot is a distraction when the campaign needs to figure out why Americans, for their own, non-Putin-generated reasons, might not be flocking to Clinton, even though she is running against a bigoted and manifestly unfit opponent. (And complaining about e-mails being made public drags the discussion back into the godforsaken realm of private servers.) And that, again, is why her answer to Holt—“This election’s really up to you”—was so strong. It wasn’t about her, or the wrongs she has undoubtedly endured. There is no question that those wrongs include sexism and slanders. And yet the simplest explanation for why many voters don’t trust Clinton is that they sense that she does not trust them. On Monday night, she looked at the camera and told them that she did.