Donald Trump lost Monday’s debate. So did Trumpism.

Donald Trump got his start in politics peddling the idea that Barack Obama was born abroad. He built his successful Republican primary campaign on a similar form of white identity politics, married to a deep and hard-line skepticism of immigration. That’s been his biggest single issue — deriding Mexicans as rapists and murderers, promising to deport 11 million undocumented immigrants, and threatening to ban Muslims from entering the country.

At Monday night’s debate, he had the perfect opportunity to tee off on these racially charged themes. Hillary Clinton had just fielded a question about “implicit bias” in policing, arguing that police needed “retraining” to deal with deep-seated psychological prejudices against African Americans.

Trump had a chance to stand up for “law and order” and aggrieved white people everywhere, to say that the problem isn’t the police but the criminals, and that Clinton was kowtowing to politically correct dogma. But he, remarkably, did the exact opposite. He accused Hillary Clinton of being the real racist, for using the racially coded term “superpredators” more than two decades ago:

I do want to bring up the fact that you were the one that brought up the words superpredator about young black youth. And that’s a term that I think was a — it’s — it’s been horribly met, as you know. I think you’ve apologized for it. But I think it was a terrible thing to say.

So here was Donald Trump, avowed opponent of political correctness, essentially accusing Hillary Clinton of committing a microaggression.

This is the untold story of the first presidential debate. Trump entered the room as the defender of a distinct set of ideas that blame America’s problems on immigrants and multiculturalism. He walked out a pale imitation of the mainstream, a man with a deeply racist past trying desperately to cover it up.

Donald Trump lost Monday night’s debate. So did the ideas he stands for.

The proposal to build a wall and make Mexico pay for it, the labeling of all Muslims as potential terrorists, the suggestion that a Mexican-American judge couldn’t hear a case involving Trump because his heritage would bias him against the magnate — these are the things that have defined Donald Trump’s candidacy.

Trumpism is a kind of authoritarian populism, one that blames immigrants and other ethnic and religious minorities for crime and terrorism. It has a lot in common with the European far right, as well as a fringe American movement called the alt-right.

“Donald Trump,” as one scholar put it, “is the first Republican in modern times to win the party’s presidential nomination on anti-minority sentiments.”

Yet you wouldn’t know it from Monday’s debate. Trump mentioned crimes committed by undocumented immigrants once, but very briefly. He didn’t talk about the wall or about rounding up and deporting millions of people. He never mentioned the purported terrorist threat posed by Muslim immigrants generally and Syrian refugees specifically. His signature themes, in other words, were just completely absent from the night.

This wasn’t for lack of opportunity. Late in the debate, moderator Lester Holt asked Trump “specifically how you would prevent homegrown attacks by American citizens.” This was a perfect opportunity for Trump to pivot to the need to screen immigrants better, to prevent Muslims from “terrorist” countries from entering and committing attacks.

He didn’t do it. Instead, he decided to attack Clinton’s record on ISIS and tout his bizarro plan to “take the oil” from Iraq. This disappointed some of his prominent alt-right fans, like Jared Taylor (the editor of the racist publication American Renaissance):

When Holt asked Trump about the racial component of New York’s “stop and frisk” policy, Trump did let loose some vintage Trumpisms about high rates of crime in inner cities, which painted American cities and minority communities in a wildly inaccurate light. But he avoided the more obvious racial dog whistles, like “black-on-black crime.” He argued that stop and frisk wasn’t racial profiling but actually a kind of gun control program:

HOLT: The argument is that it’s a form of racial profiling.

TRUMP: No, the argument is that we have to take the guns away from these people that have them, and they are bad people that shouldn’t have them.

The exchange about birtherism is a third good example. Trump has been dinged, rightly, for being completely incoherent on the subject. But he also had a weird way of punching back, arguing that it was Clinton who actually tried to racially “other” Obama by circulating pictures of him from a visit to Kenya:

I got to watch in preparing for this some of your debates against Barack Obama. You treated him with terrible disrespect. And I watched the way you talk now about how lovely everything is and how wonderful you are. It doesn’t work that way. You were after him, you were trying to -- you even sent out, or your campaign sent out, pictures of him in a certain garb, very famous pictures. I don’t think you can deny that.

So to sum up: Trump avoided bringing up his most controversial, and racially charged, comments. He avoided them even when he had clear opportunities to bring them up, and even accused Clinton of being racially insensitive.

This is a very different Donald Trump from the one who announced, in his convention speech, that “we cannot afford to be so politically correct anymore.”

The point here is not that Trump somehow successfully pivoted away from his long history of racially and religiously charged comments. No one has forgotten what he’s said.

Rather, it’s that Trump made a decision not to back off from them during the biggest moment of the general election to date. Instead of sticking up for his ideas, he just avoided them. He flinched.

This matters.

The Trumpist project, inasmuch as it exists, is about making nakedly racist and bigoted language part of the American political mainstream. It depends on breaking down barriers against openly offensive speech and normalizing the unacceptable, and it’s been working: Trump remains close to Clinton in most polls.

But his main political challenge is to take ideas that appealed to his party’s base and make them acceptable to the rest of the country. If he had given his normal spiel about banning Muslims on Monday night, and it had been debated like a normal policy proposal, the once unthinkable idea would creep even further into the mainstream. That’s how it’s worked with objectively wacky Trump ideas like “take the oil,” which he now just gets to say without anyone in the audience even batting an eye.

By opting not to make those arguments on the debate stage, Trump has given a surprising signal that he believes some of the racist language that worked in the primaries won’t fly in the general election.

That’s a problem for him, because Trump’s entire electoral strategy depends on holding on to his racist base. Trump can’t move too far away from his core message without dampening the enthusiasm for him among people who think Latinos are criminals, Muslims are terrorists, and black people are lazy.

This constituency is, as George Washington University political theorist Samuel Goldman puts it, “a minority that thinks it’s a majority.” It’s too small to guarantee electoral victories but too big to accept its minority status. Its members don’t see a need to reach out to minorities and “politically correct” whites, and they see doing so as a kind of betrayal.

Indeed, you can see this in the reaction of Trump’s supporters in the so-called alt-right movement. As my colleague Tara Golshan documents, these online racists are furious that Trump didn’t talk about what had long been his core issues. “He can’t win a debate if they ask basically no questions about terrorism or immigration,” one user at the alt-right-friendly message board 4chan writes.

Internet trolls, of course, aren’t a huge constituency. But the voters who share their concerns about minorities and immigration are. While Trump’s campaign has shown that this group can power a victory in the Republican primary, it may now be exposing the limits of this group’s influence on American politics writ large.

There are still two more debates and 43 more days in the election — plenty of time for Trump and his supporters to wreak more havoc.

For now, though, score one for the basic norms of American democracy and values.