President Donald Trump on Friday posted an extremely dubious tweet alleging people from Muslim-majority countries are crossing the border with bad intentions, and leaving prayer rugs behind.

Citing a report that hinged on one anonymous source, Trump tweeted: “Border rancher: ‘We’ve found prayer rugs out here. It’s unreal.’ Washington Examiner.”

“People coming across the Southern Border from many countries, some of which would be a big surprise,” he added.

Border rancher: “We’ve found prayer rugs out here. It’s unreal.” Washington Examiner People coming across the Southern Border from many countries, some of which would be a big surprise. — Donald J. Trump (@realDonaldTrump) January 18, 2019

That was indeed the headline of a Washington Examiner article published on Wednesday, but the story itself presents no evidence for its central claim beyond one anonymous account — and even if it were true, prayer rugs themselves pose no threat to national security.

It’s clear Trump was using the story to stoke fears about Muslims and shore up support for his proposed wall along the southern border, something he has said he is proud to shut down the government over. The partial shutdown began on December 22, and Trump hasn’t budged from the $5.7 billion for the wall he is demanding.

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The flimsy basis of the Examiner’s story

The Washington Examiner’s piece is centered on a single, anonymous rancher who presents no evidence for the claim that prayer rugs are being found along the border.

“There’s a lot of people coming in not just from Mexico,” the woman is quoted as saying in the piece. “People, the general public, just don’t get the terrorist threats of that. That’s what’s really scary. You don’t know what’s coming across. We’ve found prayer rugs out here. It’s unreal. It’s not just Mexican nationals that are coming across.”

If prayer rugs were indeed found, you might expect the article to include a photo of one of them. But it doesn’t. Instead, the rancher — who admits in a video accompanying the piece that she’s never seen “Middle Easterners” crossing the border — is photographed holding a bottle.

In response to widespread criticism of the article, Susan Ferrechio, the Washington Examiner’s chief congressional correspondent, simply criticized the way others pointed out its flimsy sourcing.

Mainstream media has led the way with anonymous sourcing, single sourcing, claims with no viewable evidence. It's "very bad" if you disagree with the story. https://t.co/rKDv8xsiWa — Susan Ferrechio (@susanferrechio) January 18, 2019

Left unexplained by the article is why Muslims who presumably traveled through Mexico to cross the border would carry their prayer rugs with them for hundreds or thousands of miles, just to leave them behind in Texas.

There’s little evidence would-be terrorists are trying to enter the country through the southern border

Data from Customs and Border Protection (CBP) indicates that people from Muslim-majority countries are apprehended crossing the southern border between ports of entry at vanishingly small rates.

In 2017, for instance, six Syrians, 10 Jordanians, and 14 Saudis were apprehended trying to cross the border — compared to 16,000 Guatemalans.

And of course, just because a person is from the Middle East or a Muslim who uses a prayer rug does not mean that they’re a terrorist.

A 2017 State Department report found that there is “no credible evidence terrorist groups sent operatives via Mexico into the United States.” A recent Cato Institute study found that there were zero cases of people being injured or killed on US soil by people who entered the country illegally from 1975 through the end of 2017.

Conservatives have a long history of making unfounded claims about prayer rugs

Conservatives have a storied history of using dubious stories about prayer rugs to stoke fears about Muslims entering the country through the southern border.

In July 2014, Breitbart published a piece with the screaming headline, “MUSLIM PRAYER RUG FOUND ON ARIZONA BORDER BY INDEPENDENT AMERICAN SECURITY CONTRACTORS.” The piece was accompanied with a photo of the purported “prayer rug.” But there was just one problem — close examination revealed that the object in question was in fact an Adidas soccer jersey.

At the 2014 Values Voters Summit a couple months later, then-Texas Lieutenant Governor David Dewhurst claimed that “prayer rugs have recently been found on the Texas side of the border in the brush.” But Dewhurst presented no evidence for his claim, which Politifact ultimately rated “Pants on Fire.”

Desperate times, desperate tweets

Last month, Trump decided to shut down the government instead of supporting bipartisan legislation that would’ve kept it open, but not funded his border wall.

Nearly a month later, polling indicates that a majority of Americans don’t like the shutdown and are blaming Trump for it. Separate polling indicates that Trump’s wall remains as unpopular as ever, despite the president’s efforts to convince people that the situation along the border is a crisis.

So far, Trump has shown little willingness to negotiate and has been trying to tweet his way out of it. Tweets like the prayer rug one suggest that Trump — who has a long history of making baseless, fear-mongering claims about Muslims — is resorting to increasingly desperate measures.