In Paris on Thursday, Donald Trump said, “A lot of people don’t know” that “France is America’s first and oldest ally.” That may be true. But commentators noted that when Trump uses the “a lot of people don’t know” formulation, it’s usually a sign that he didn’t know himself.

It’s called projection. And Trump does it with remarkable frequency. You may have noticed that over the last few days, Trump and his allies have begun talking a lot about the Hillary Clinton campaign’s alleged collusion with the governments of Russia and Ukraine. On Wednesday morning, for instance, Trump tweeted a quote from the conservative Washington Times that claimed, “Democrats have willfully used Moscow disinformation to influence the presidential election against Donald Trump.”

Why is Trump suddenly interested in the Democratic Party’s ties to the Russian government? Perhaps because on Monday, The New York Times broke a blockbuster story about his campaign’s ties to the Russian government.

It’s a pattern that has repeated itself again and again since Trump launched his presidential bid. Last June, as Hillary Clinton was finishing up her primary campaign, she began testing a line that she would use against Trump throughout the summer and fall: “He’s temperamentally unfit.” In her speech at the Democratic National Convention, she added that, “A man you can bait with a tweet is not a man we can trust with nuclear weapons.” Soon, Trump was making the same argument about her. “I don’t think she’s all there,” he declared in August. In September he called her “trigger-happy” and “very unstable.”

Another, related, Clinton theme was the impact of Trump’s bad behavior on America’s children. In its first negative ad, the Clinton campaign depicted children watching Trump’s crude, violent, and demeaning comments on TV. Trump soon picked up the theme himself, asking a North Carolina crowd, “What should these parents tell their children about Hillary Clinton’s attacks?”

Then in August, after Trump named Steve Bannon to be his campaign’s chief executive, Clinton announced she would give a speech on Trump’s ties to white nationalists. That same day, Trump told a Mississippi crowd that, “Hillary Clinton is a bigot who sees people of color only as votes, not as human beings worthy of a better future.”

The following month, as journalists pressed him to state definitively that he believed President Obama was born in the United States, Trump announced that, “Hillary Clinton and her campaign of 2008 started the birther controversy.” In October, as numerous women came forward to accuse Trump of sexual harassment, he began accusing Clinton of abusing women.

Trump invited three alleged victims of Bill Clinton’s sexual harassment to the second presidential debate, and declared from the podium that, “Hillary Clinton attacked those same women and attacked them viciously.”

During the primaries, Ted Cruz actually tried to diagnose this Trump habit. “This man is a pathological liar,” Cruz insisted. “He lies practically every word that comes out of his mouth.” And in “a pattern that I think is straight out of a psychology textbook, his response is to accuse everybody else of lying.”

Why does Trump do this? Sigmund Freud believed people project onto others impulses that they cannot accept as their own. Erick Erickson suggested that projection may be a response to crisis or extreme stress. Others have linked it to narcissism.

The more important question is why it works, at least among Trump’s base. One answer may be that Trump supporters embrace his projection because they’re doing it themselves. Consider Trump’s claim that Hillary Clinton is the real bigot. On its face it’s odd given that Clinton enjoyed overwhelming African American support. But it’s easier to understand the statement’s appeal when you realize that, according to a November 2016 Huffington Post/YouGov poll, Trump supporters were twice as likely to say whites face a “lot of discrimination” as they were to say blacks face a lot of discrimination. When it came to bigotry, in other words, Trump’s overwhelmingly white fan base may have been projecting, too.

Or take Trump’s claim that Clinton was the real harasser of women. It’s easier to understand when you realize that more than 40 percent of Trump supporters think, “society seems to punish men just for acting like men,” according to a PRRI/The Atlantic poll. And that in a May 2016 Morning Consult poll, 49 percent of Republican men who had an unfavorable opinion of Clinton called her a sexist. A November ABC/Washington Post poll found that 87 percent of Republicans considered Trump more honest than Clinton despite the fact that Politifact judged 50 percent of the Clinton statements they evaluated to be “true” or “mostly true” compared to only 17 percent of Trump’s.

Maybe Trump’s supporters believe his projections because he’s not the only one who wants to escape from reality.