At Sunday’s debate, Donald Trump revealed that he is not running to be America’s president so much as its dictator.

The debate’s most unnerving moment came early. “If I win, I'm going to instruct the attorney general to get a special prosecutor to look into your situation, because there's never been so many lies, so much deception,” Trump told Hillary Clinton.

“It's just awfully good that someone with the temperament of Donald Trump is not in charge of the law of our country,” Clinton shot back.

Trump, determined as always to make subtext into text, left no room for confusion. “Because you’d be in jail,” he said.

So there it was. The Republican nominee for president of the United States has promised to imprison his opponent if he wins the election. “This is what happens in dictatorships,” wrote the New York Times’ Max Fisher. “Not democracies.”

Tonight was the night when our worst fears about Donald Trump’s autocratic impulses were confirmed. Trump is, by his own account, vengeful. “When someone intentionally harms you or your reputation, how do you react?” he wrote in 2007. “I strike back, doing the same thing to them only ten times worse." And so it’s long been obvious that Trump might be vengeful as president — a possibility Vox’s Dara Lind explored brilliantly in this feature.

But Trump had never simply come out and said he would use the power of the state to punish his political enemies. In June he inched that way, telling a crowd that he was starting to agree with a popular chant at his rallies, “lock her up.” Tonight, he went all the way.

As bad as the recording of Trump bragging about sexual assault is, this is scarier — this is a major presidential candidate promising to violate our most basic democratic norms if elected.

When Trump said he'd throw her in jail my first thought went back to Putin doing that to Khodorkovsky. — Jim Goldgeier (@JimGoldgeier) October 10, 2016

In Trump’s defense, he might simply be confused. Later in the debate, he showed a startling lack of familiarity with the basic structure of America’s political system.

The exchange was over the carried-interest loophole — a quirk of the tax code that allows hedge fund managers to pay a lower tax rate on their share of their fund’s profits. Trump bragged that he wanted to get rid of it, and said Clinton wanted to leave it be. This is not true — Clinton has long pushed to close the loophole, and she said so.

“I've been in favor of getting rid of carried interest for years,” Clinton replied. “Starting when I was a senator from New York.”

“Why didn't you do it?” Trump asked. “Why didn't you do it”

“Because I was a senator with a Republican president,” Clinton replied.

“If you were an effective senator, you could have done it,” Trump shot back.

This is, to put it mildly, not how the American political system works. Trump has always had an ambitious view of executive power, but here he showed a basic ignorance of the system’s basic functioning. Even an effective senator cannot, on their own, overwhelm a presidential veto.

But Trump doesn’t seem to care. As political scientist Brendan Nyhan has written, Trump “exploits the appeal of presidential omnipotence by contrasting his supposedly decisive style of business leadership as a real estate magnate with the compromises, inertia and policy failures that are inevitable in politics.” The hope was always that Trump knew better than his grand promises suggest. Tonight, he made it clear he doesn’t.

Many of Trump’s supporters hope that he’ll be guided and constrained by more seasoned, temperate advisers while in office. Tonight he proved that hope absurd. He began the evening by inviting three women who have accused Bill Clinton of sexual misconduct to a press conference — an insane strategy that virtually everyone in the Republican Party has been begging Trump to abandon.

Later in the night, Trump was asked about his running mate’s statements on Russia, and he made clear how little influence Pence has over his campaign, and how little interest Trump has in his counsel. "He and I haven't spoken, and I disagree," Trump brutally replied.

The message: Trump listens to no one, and is held back by no one. A Trump presidency won’t secretly be a Mike Pence presidency, or a Paul Ryan presidency, with Trump occupying a more ceremonial role. It will be him, and he will be doing whatever he damn well pleases.

Then there was the question where a young Muslim woman asked Trump what he would do about the rising tide of Islamophobia in America, and he answered by repeating false, Islamophobic myths on television. “In San Bernardino, many people saw the bombs all over the apartment of the two people that killed 14 and wounded many, many people. … Muslims have to report the problems when they see them.” This simply never happened, and so we saw a presidential hopeful respond to a question about staunching Islamophobia by feeding it.

This was a scary night in American politics. This was an American presidential candidate promising to rule like Vladimir Putin.

I have said this before, but the compliment Donald Trump deserves to be paid is that he has never hidden his true nature. He has never obscured his cruelty, or his misogyny, or his greed, or his dishonesty, or his will to power. Tonight, he was perfectly clear about the autocratic direction in which he wants to take the country, and now it is up to us to decide if we want to go there.

Watch: Trump threatens to imprison Clinton if elected