On Monday night, President Donald Trump held a rally in El Paso, Texas. He chose the location based on his claim, delivered in last week’s State of the Union address, that a border wall had rescued the city from rampant crime. By the time Trump arrived, fact-checkers had demolished this lie, pointing out that the wall had no effect. But Trump told his followers to dismiss the numbers and trust him instead. And they did, because this is a measurable fact about Trump supporters: They’re willing to reject all other sources of information—crime statistics, intelligence agencies, even conservative media—when the president tells them to do so.

Trump first told his lie a month ago. “A wall was put up,” he said, and El Paso “went from being one of the most dangerous cities in the country to one of the safest cities in the country overnight.” Law enforcement data showed that every part of this statement was false: El Paso hadn’t been dangerous, its long-term decline in crime mirrored declines in nonborder cities, and crime in the city didn’t fall—in fact, it leveled off from what had been a trend downward—after a border fence was built there.

Fact-checkers laid out these numbers for the president. He ignored them. In his State of the Union address, he repeated the falsehood. On Monday, after Fox News debunked it, he instructed his fans in El Paso to reject the official figures. “I spoke to people that have been here a long time,” Trump told the crowd. “They said when that wall went up, it’s a whole different ballgame.” Having substituted his alleged anecdotes for data—Trump, the crusader against anonymous quotes, named none of his sources—he then conducted a voice vote to settle the matter. “Is that a correct statement?” he asked, prodding his audience. The crowd cheered.

Half of Trump voters said they trusted little to none of the government’s figures.

Trump told the attendees to disbelieve news organizations and public officials who cited the data. “I don’t care whether a mayor is a Republican or a Democrat,” he scoffed, referring to El Paso Mayor Dee Margo, a Republican who had tried to correct the president. “They’re full of crap when they say it hasn’t made a big difference.” He went on: “I heard the same thing from the fake news. They said, ‘Oh, crime actually stayed the same.’ Didn’t stay the same! It went way down. … These people, you know, you’d think they’d want to get to the bottom of a problem … not try and pull the wool over everybody’s eyes.”

Then Trump delivered his closing pitch, a direct appeal to intuition over evidence. You don’t need to check the numbers, he argued, since you already know walls work. “It’s fake news. I’m telling you, it’s just fake news,” the president jeered. “And you know what? You wouldn’t even have to know. You can say that automatically, without even knowing. It’s, like, it’s obvious, it’s common sense.”

Trump’s message was a recipe for incurable ignorance: Reject all contrary evidence as biased. Reject anyone who reports that evidence. Rely on your leader’s anecdotes. Trust the uninformed consensus of your friends. Respond automatically. And ignore anyone who says you’re a sucker. You’re not being credulous. You’re being vigilant against the fakers. You’re “the smart ones.”

This is insanity. But among Trump supporters, it’s the norm. Consider recent surveys on public trust in data. A year ago, an Economist/YouGov poll asked, “How many of the statistics reported by the government are reliable and accurate?” Most people who had voted for Hillary Clinton in 2016 said most government figures were accurate. Only 15 percent of Trump voters agreed. Half of Trump voters said they trusted little to none of the government’s figures. Only 29 percent of adults as a whole said they considered Trump honest and trustworthy, but 74 percent of Trump voters did. That’s five times the share of Trump voters who said they trusted statistics collected by the government.

Trump supporters specifically rejected law enforcement data. The YouGov survey asked: “The government has reported a steady decline in the rate of violent crime over the last twenty years. Do you think the government is correct and the rate of violent crime has decreased, or do you think the rate of violent crime has remained the same or even increased over the past twenty years?” Clinton voters were twice as likely to accept the data (43 percent) as to reject it (20 percent). Trump voters were twice as likely to reject the data (39 percent) as to accept it (17 percent).

The president’s devotees also trust him over the intelligence community. In July, a Quinnipiac University poll asked, “Who do you trust more to tell you the truth about important issues: President Trump or the U.S. intelligence agencies?” In every demographic subsample, including noncollege whites, fewer than one-third of respondents favored Trump. Only one group sided with him: Republicans. By a margin of more than 2 to 1, they rejected the intelligence agencies and chose to trust the president.

Trump’s followers don’t just scorn the liberal media. They dismiss any reporting that contradicts the president, even if it comes from outlets they normally trust. In July, an NPR/PBS/Marist poll asked, “Who do you trust more: your favorite news source or Donald Trump?” For respondents on the political right, this question pitted Trump’s credibility not against CNN or the New York Times but against friendly sources such as Fox News. Nevertheless, these respondents picked Trump. While voters as a whole trusted their favorite news source over Trump (62 percent to 29 percent), Trump supporters chose the president, 65 percent to 24 percent. Among Republicans, the gap was even wider: 70 percent trusted Trump more than they trusted their favorite news source.

Despite Trump’s torrential dishonesty—nearly 8,500 false or misleading statements, at last count—close to half of his supporters say he has never lied. Last May, an Economist/YouGov survey asked, “Do you think Donald Trump has or has not ever lied to the American people?” Nineteen percent of U.S. adults said he had never lied. Among Trump voters, 40 percent said he had never lied. That’s more than the 31 percent of Trump voters who were willing to say he had lied even once.

So when Trump told the folks at that rally in El Paso to trust him over all contrary evidence—law enforcement data, the local Republican mayor, fact checks by Fox News—he wasn’t brainwashing them. He was telling them what they already believed. Trumpism isn’t about a border wall, any more than it’s about patriotism or conservatism. It’s about unshakeable faith in one man. A liar.

Thanks to Arthur Davis, Michelle McEwen, and Laura Wagner for research assistance.