'Build a wall and crime will fall,' says Trump. But it's been falling anyway.

As the partial shutdown of the federal government drags on into its 33rd day over Donald Trump’s demand that Congress allocate $5.7 billion for a barrier along the U.S. border with Mexico, the president unveiled a new rhyming slogan Wednesday to try to convince more Americans of the logic of his proposal.

Trump, of course, has long blamed undocumented immigrants for higher crime rates in the United States. “They’re bringing drugs. They’re bringing crime. They’re rapists,” Trump said of Mexican immigrants as he kicked off his his presidential campaign in 2015.

On Tuesday, before his slogan had taken final form, the president pushed its central claim.

But statistical data does not seem to back the president’s assertions, notwithstanding a handful of notorious crimes by immigrants that he mentions repeatedly in his speeches.

A 2018 study by the Cato Institute, for example, found that native-born U.S. residents are much more likely to be convicted of a crime than immigrants in the country illegally.

A separate study published last March in the journal Criminology found that states with more undocumented immigrants have lower crime rates than those with fewer.

And crime has been falling steadily even without a wall. While the share of the foreign-born U.S. population rose from 7.9 percent to 13.1 percent between 1990 and 2013, FBI figures show the violent crime rate declined by 48 percent and property crime fell by 41 percent.

Of course, Trump’s claim of lower crime rates holds if one counts illegal immigration itself as a crime, but even that has fallen significantly. Figures provided by the U.S. Customs and Border Patrol show that the total number of arrests for illegal border crossings fell in 2017 to the lowest level since 1971. The Department of Homeland Security also estimates that undetected illegal border crossings have dropped dramatically in recent years.

What has risen over the past year is the number of people seeking asylum in the U.S., including many families with children, usually fleeing gang violence and crime in their homelands. And for the most part they are not trying to sneak into the country undetected; if they make it across the border they generally seek out Border Patrol agents to surrender to and apply for asylum. Last year’s dreaded “caravan” from Central America mostly headed for official ports of entry and wound up in camps in Mexico, waiting for their asylum claims to be processed.

Trump’s related claim, that a wall will stop illegal drug trafficking, is contradicted by evidence that most drugs are actually smuggled across the border hidden in vehicles at manned border crossings, or by air, sea or tunnels.

While Trump’s new slogan may not be backed by statistical evidence, it seems unlikely that the president will stop using it anytime soon. In fact you might expect to hear it at his next rally.

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