Trump: after Mollie Tibbetts’s murder, “we need the wall”

President Donald Trump on Wednesday tweeted about the death of Mollie Tibbetts, a 20-year-old student from Brooklyn, Iowa, to push his immigration agenda.

“Mollie Tibbetts, an incredible young woman, is now permanently separated from her family,” Trump said in a Twitter video. “A person came in from Mexico illegally and killed her. We need the wall. We need our immigration laws changed. We need our border laws changed.”

Tibbetts’s body was found on Tuesday, and police charged Christhian Bahena Rivera, who authorities said is an undocumented immigrant, with first-degree murder for her death.

There are a few things going on in Trump’s comments. First, the language he uses — that Tibbetts was “permanently separated from her family” — is a reference to Trump’s family separation policy, suggesting that the policy, in which border agents separated children from their parents seeking asylum at the US-Mexico border, was justified because it kept American families protected and together. (Some of Tibbetts’s relatives, for their part, have asked the public not to focus on Rivera’s immigration status.)

Trump’s broader point, though, is making a direct connection between immigration and crime. “This is one instance of many,” Trump said in the video. “We have tremendous crime trying to come through the borders.”

Trump’s underlying assumption, though, is wrong: In the US, immigrants are much less likely to commit crimes than their native-born peers.

Take this chart from the Pew Research Center, which depicts the prevalence of criminal activity among different generations of immigrants and native-born Americans:

As the Pew chart shows, first-generation immigrants are considerably less likely to commit crime. To the extent that second-generation immigrants commit crime at closer rates to that of native-born Americans, that’s actually them ditching the approach of their better-behaved parents and moving closer to the American norm of more criminal activity.

Other research supports this point. A 2015 report from the American Immigration Council, an advocacy group, concluded that native-born Americans are more likely to be incarcerated than Central American immigrants, and recent increases in immigration occurred as crime actually fell in the US.

This was found to be the case a whole century ago, too — when the Dillingham Commission in 1911 concluded, “No satisfactory evidence has yet been produced to show that immigration has resulted in an increase in crime disproportionate to the increase in adult population. Such comparable statistics of crime and population as it has been possible to obtain indicate that immigrants are less prone to commit crime than are native Americans.”

This research can be messy, since it doesn’t always distinguish between undocumented and documented status. That distinction often isn’t possible, since the crime and immigration data frequently isn’t granular enough.

But immigrants, whether documented or not, generally come to the US for similar reasons — to make better lives for themselves. That creates a selection bias effect: If immigrants are trying to come to the US to find a better job or escape crime and violence in Latin America, they’re simply much less likely to be interested in committing crimes over, say, finding work or creating a safe environment for their children.

Still, as with any large group of people, some immigrants will at times do bad, even terrible things. What’s important to remember is that they do not represent their broader group, at least based on the best evidence.