Donald Trump is mentally ill. After 16 months of campaigning and three general election debates, this has become all too clear. Trump sees himself as the victim of a web of conspiracies encompassing House Speaker Paul Ryan, the FBI, the CIA, and the Iraqi military. He sees events in his life—women who claim to have met him, violence by supporters at his rallies—as tentacles of these plots. He refuses to accept the outcome of the election, and he demands that his opponent be jailed, not because Trump is cynical but because he is paranoid.

In Wednesday’s debate, as in previous encounters with Hillary Clinton, Trump kept his composure for the first 25 minutes. But he couldn’t hide his self-preoccupation. The first question was about the Supreme Court. Trump answered it by complaining that Justice Ruth Bader Ginsburg had made “inappropriate statements towards me.” Later, Trump did what he has done at campaign rallies: recast bad news for others as good for himself. “The end of last week, they came out with an anemic jobs report,” he said. “I should win easily, it was so bad.”

Half an hour into the debate, Clinton challenged Trump to condemn Russia’s attempt to influence the election through cyberespionage. Trump responded with his usual pro-Russian arguments: that Russian dictator Vladimir Putin is too strong to play “chicken” with, that we should try to get along with Putin, and that we should soften our commitments to NATO countries. But Trump also rejected the verdict of U.S. intelligence agencies:

Clinton: We have 17 intelligence agencies, civilian and military, who have all concluded that these espionage attacks, these cyber-attacks, come from the highest levels of the Kremlin and they are designed to influence our election. …

Trump: She has no idea whether it’s Russia, China, or anybody else.

Clinton: … Do you doubt 17 military and civilian agencies?

Trump: And our country has no idea.

The moderator, Chris Wallace of Fox News, affirmed Clinton’s assessment: “The top national security officials of this country do believe that Russia has been behind these hacks.” But Trump wouldn’t budge. He refused to trust American intelligence officials, even—or particularly—in a dispute with Putin.

Twenty minutes later, Wallace turned to Trump’s treatment of women. “Nine women have come forward and have said that you either groped them or kissed them without their consent,” Wallace observed. “Why would so many different women, from so many different circumstances over so many different years … why would they all make up these stories?”

Trump responded with a demonstrably bogus denial: “I didn’t know any of these—I didn’t see these women.” He accused Clinton of orchestrating their allegations: “I believe it was her campaign that did it. … She got these people to step forward. … [It] is all fiction, all fictionalized, probably or possibly started by her and her very sleazy campaign.”

In the same answer, Trump blamed Clinton for violence at Trump’s campaign rallies. He cited a recording in which a Democratic operative had discussed how to provoke Trump supporters by wearing anti-Trump or pro–Planned Parenthood T-shirts. Trump took no responsibility for having encouraged assaults at his rallies. “She talks about violence at my rallies, and she caused the violence,” he said of Clinton.

Trump tried to change the subject to Clinton’s emails. But then he had to explain why FBI Director James Comey, a longtime Republican, had decided after investigating the emails that Clinton shouldn’t be prosecuted. “What the FBI did” was “a disgrace,” said Trump. In rallies over the past week, Trump has all but indicted the bureau, claiming that Clinton and her henchmen have “corrupted the director of the FBI,” that “this is a conspiracy against you, the American people,” and that a special prosecutor must be appointed to “investigate the investigation.”

With half an hour left on the clock, Trump lost it. Wallace asked him: “You have been warning at rallies recently that this election is rigged and that Hillary Clinton is in the process of trying to steal it from you. … Do you [pledge] that you will absolutely accept the result of this election?” Trump refused to say yes. “I will look at it at the time,” he said. For one thing, Trump argued, there are “millions of people that are registered to vote that shouldn’t be registered to vote.”

That might be a valid reason to challenge the election results, if there were evidence of significant voter fraud, which there isn’t. But Trump gave two more reasons why he might not accept the election’s outcome. First, said Trump, “the media is so dishonest and so corrupt … and they’ve poisoned the mind of the voters.” Second, he complained:

She shouldn’t be allowed to run. It’s crooked. She’s guilty of a very, very serious crime. She should not be allowed to run. And just in that respect, I say it’s rigged, because she should never—Chris, she should never have been allowed to run for the presidency based on what she did with e-mails and so many other things.

These two arguments, not Trump’s allegations of voter fraud, were the bombshells of the evening. They don’t require evidence of election tampering or even a tight margin of victory. All they require is biased media coverage—a perpetually asserted problem in nearly every country—or a legal proceeding that didn’t turn out the way some politician, general, or warlord hoped it would. Trump is laying the groundwork for any candidate to reject democratic outcomes when the press criticizes that candidate or when the candidate insists, based on the second-guessing of courts and prosecutors, that his opponent belongs in jail. This kind of rationalization is how dictators come to power. It’s how their enemies end up imprisoned or executed.

Wallace pressed Trump once more. “There is a tradition in this country” of “the peaceful transition of power,” said Wallace. “The loser concedes to the winner,” and “the country comes together in part for the good of the country. Are you saying you’re not prepared now to commit to that principle?” Again, Trump refused: “I will tell you at the time. I’ll keep you in suspense.” Why the suspense? Because if Trump commits to a peaceful transition, he loses his leverage. His leverage is the threat of civil unrest. It’s a hostage situation, and we’re the hostages.

Trump wasn’t finished with his accusations. As the debate turned to foreign policy, he ridiculed Iraq’s attempt to recapture Mosul. “The only reason they did it is because she’s [Clinton] running for the office of president, and they want to look tough,” said Trump. “She wanted to look good for the election. So they’re going in.” It wasn’t clear how many players in the Mosul operation—the Iraqi army, American troops, Kurdish forces, Sunni fighters, and Shiite militias—Trump was implicating in the conspiracy.

Trump’s fantasies of persecution reach deep into his party. As Clinton pointed out, he has previously accused Republicans of rigging the Iowa caucuses and the Wisconsin primary against him. In the debate, Trump acknowledged his beef with President Ronald Reagan in the 1980s and complained—as Wallace tried in vain to move on to another subject—that Reagan was soft on trade. A week ago, at a rally in Florida, Trump fumed that Ryan wasn’t supporting him, that GOP leaders were “not putting their weight behind the people,” and that “there’s a whole sinister deal going on” inside the party.

Trump’s refusal to endorse a peaceful transition of government shouldn’t surprise anyone who has watched his rallies. Last weekend, he called Barack Obama our “quote, president.” Trump suggested that Obama—whose eligibility for the presidency Trump challenged for five years—was elected in part through voter fraud. Trump also declared that Clinton “should be locked up,” that her attorneys should be jailed, and that “she shouldn’t be allowed to run for president.”

If you’re one of the millions of Americans who doesn’t like Clinton or doesn’t agree with her agenda, it’s hard to face the truth of this election. In a two-party system, you ought to get a choice between two plausible candidates. But sometimes it doesn’t work out that way. When one party nominates a madman, all you can do is vote against him. And you’d better do at least that much. Because if you don’t, you’ll get only one choice in the next election, too. And this time, it will be the madman.

Read more Slate coverage of the 2016 campaign.