Immigrants and supporters gather 3,000 strong at Columbus Circle to protest & march against President Donald Trump's proposed immigration policies in New York City November 13, 2016.

Immigrants and supporters gather 3,000 strong at Columbus Circle to protest & march against President Donald Trump's proposed immigration policies in New York City November 13, 2016. a katz/shutterstock

Illegal Immigration Doesn’t Cause Crime

A review of the available evidence shows no link between illegal immigration — currently at a decade-long low — and crime.

No president in U.S. history has staked as much of his administration on fighting immigration as Donald J. Trump. This chart my colleague David Montgomery whipped up offers just one glimpse into that: It shows how often each president has used immigration-related words in annual State of Union speeches. Trump’s attention to the topic, which was on display again last night, towers over his 44 predecessors.

It’s not a surprise. Combating immigration was the number-one issue during Trump’s presidential campaign, and since he has taken office, this has been an arena in which he has arguably been most productive, as far as succeeding in turning his rhetoric into policies that have affected the lives of millions of people.

He’s been able to push through a ban on the entry of people from certain Muslim-majority countries—which, after three iterations, was able to pass legal muster. His administration has slashed refugee resettlement numbers drastically. And most recently, he ordered migrants at the southern border to remain in Mexico while they go through their asylum process. His administration has also changed many of its visa processing rules to make it even more difficult to obtain employment-based visas, putting further pressure on an already-broken legal immigration pipeline.

But Trump has not been able to deliver on the keystone promise of his campaign: a physical border wall. The tussle between him and Congress over funding for this pet project caused the longest shutdown in U.S. history—and in just few days, it may all go back at square one.

In his State of the Union address, the president resumed stumping for the wall by doing what he’s become proficient at: weaponizing migration. “The lawless state of our southern border is a threat to the safety, security, and financial well-being of all America,” he said. “We have a moral duty to create an immigration system that protects the lives and jobs of our citizens.” He also announced that he had ordered another 3,700 troops to the border to “prepare for the tremendous onslaught” of migrants now approaching, raising the specter of another “caravan” invasion.

The core of Trump’s argument is that a wall is needed because there’s a flood of immigrants illegally crossing the border, driving up crime and violence in cities nationwide. It’s such a foundational assertion that even foes of the president often don’t pause to think critically about it any longer; instead, they get tied up debating logistical and cost-related points. So below are some big questions related to claims typically made around crime and immigration—responses to which come from numerous peer-reviewed studies, working papers, analyses, and government data CityLab has sifted through.

Are large numbers of migrants crossing the border?

Illegal immigration is the lowest it has been in over a decade. But a record number of families with children are crossing the border and turning themselves in to Border Patrol, in order to claim asylum: Border Patrol’s apprehension numbers for financial year 2019 show that uptick. As Vox’s Dara Lind recently put it, there is a crisis at the border—it’s just not exactly the one the government is talking about. The problems at the border lie in the humanitarian need and the lack of capacity—and will—to meet it.

Do immigrants cause crime?

Sure, individual immigrants commit crimes. But a review of available research (a study of studies, if you will) does not support the claim that migrants are more likely to engage in criminal behavior than native-born Americans. In fact, researchers have often observed the opposite relationship.

One (imperfect) way to think about a group’s relationship to crime is to see how many people from that group end up in prison—and why. An analysis by Michelangelo Landgrave and Alex Nowrasteh at the libertarian Cato Institute from 2016 found that legal and undocumented immigrants were less likely to be incarcerated than native-born Americans—and that likelihood appeared to be decreasing over time. Another one out of the Cato Institute focused specifically on the state of Texas. It showed that in 2015, undocumented immigrants had a criminal conviction rate 50 percent below that of native-born Americans. The conviction rate of those here legally was 66 percent below.

It does not appear that these are rates are low because immigrants found committing crimes were swiftly deported. A working paper from 2007 released by the National Bureau of Economic Research (NBER) concluded that immigrants who come to the country either self-select so that they are less likely to cause crime to begin with, or they have much more to lose by committing crime and therefore are more easily deterred. (Some argue that even if people have committed crimes, they are human and still have the right to migrate. But that’s a deeper question for another time...)

But what about that report by the Justice Department and DHS showing that the large percentage of inmates in federal prison were foreign-born?

It is true that non-citizens make up around 22 percent of the Federal Bureau of Prisons (BOP) population. But as the Bipartisan Policy Center’s Cristobal Ramón points out in a blog post, that population includes those whose immigration offenses have been prosecuted as federal crimes. In other words, they’re in prison for being immigrants, not for being criminals. The “prevalence of undocumented and other immigrants is largely the result of immigration enforcement priorities, not necessarily increased rates of overall criminality among immigrants,” Ramon concludes.

All this comes back to what immigration scholars call “crimmigration”—the intertwining of immigration and criminal law. Starting in the Reagan administration, non-citizens increasingly faced a risk of deportation if they committed small offenses; simultaneously, illegal migration—crossing the border unauthorized or reentering after being deported—was more harshly prosecuted. Those two trends together have led to a system that emphasizes imprisonment and removal, César Cuauhtémoc García Hernández, a law professor at the University of Denver, told me in 2016. It also tags offenders with criminal records.

And cities with large immigrant populations—are they more likely to be ridden with crime and violence?

Not really!

Here are some studies that tackle different parts of that question.

  1. 2018 study published in the journal Criminology examines the relationship between the unauthorized immigration and violent crime (offenses like murder, rape, robbery, and aggravated assault) in 50 states and D.C. between 1990 to 2014. It found the link to be “generally negative, although not significant in all specifications.” Another study by the same author found that illegal immigration had no effect on lower-level crimes like DUI deaths, and correlated with decreases in DUI and drug arrests.
  2. In 2018, a study in City & Community by Javier Ramos and Marin Wenger examined 6,660 tracks in 55 cities and found a positive relationship with robberies at the census-tract level—on average—a finding that has a nuanced explanation the authors discuss in the paper. At the city level, the relationship with crime was still negative.
  3. 2014 study in the American Law and Economics Review looked specifically at Mexican migrants (long a target of the president’s ire) in various American cities. The researchers concluded that “Mexican immigration tends to be associated with neither higher nor lower levels of overall crime.” (Other studies have also found lower levels of crime and violence in Hispanic immigrant communities.)
  4. Researchers from four universities came together to analyze the immigration rate and crime in 200 big and small metro areasbetween 1970 and 2010. Their findings showed that where immigration grew, violent and property crime generally decreased. The Marshall Project extended that data to 2016 in a collaboration with the New York Times; the findings held.
  5. Finally, in 2010, sociologist Tim Wadsworth examined immigration, robbery, and homicide in 459 U.S. cities between 1990 and 2000. He also found that places with greater increases in new immigrants saw the largest drop in these types of crime during this time, his study found.

What about in border cities?

In the SOTU speech, Trump repeated a claim he’s made before about how physical walls made the border cities of El Paso and San Diego safer. “The border city of El Paso, Texas, used to have extremely high rates of violent crime—one of the highest in the entire country, and considered one of our nation’s most dangerous cities,” he said. “Now, immediately upon its building, with a powerful barrier in place, El Paso is one of the safest cities in our country.”

But that’s not quite it. In Texas, all the state’s border communities have the some of the lowest crime rates compared to similar cities, despite their proximity to the “dangerous” Mexican border, The Texas Tribune reports. In El Paso, crime had started dropping before 2008, when the border fence there went up. In fact, in 2001, researchers Matthew Lee, Ramiro Martinez, and Richard Rosenfeld analyzed homicide rates at the neighborhood level in Miami, San Diego, and El Paso—three cities abutting a contiguous U.S. boundary that saw influxes of immigrants in the 1980s and 1990s. They found “either no relationship or a significant negative relationship between homicide and recent immigration.”

What about refugees—do they cause crime?

Historically, the United States led the world in refugee resettlement.That ended with the rise of the Trump administration, which has reduced the number of displaced persons the country will accept to record lows, citing public safety and economic costs. But refugees don’t appear to cause crime either. According to an analysis by New American Economy (NAE), a bipartisan group advocating for immigration reform, the 10 cities that received the most refugees in the last ten years saw drops in crime—sometimes, dramatic ones.

Getting rid of refugees also doesn’t decrease crime. The Immigration Policy Lab, a migration research organization, analyzed county-level crime rates after Trump’s policy changes caused a huge drop in refugee resettlement in 2017. The researchers observed no significant changes.

What about in the past? Has immigration ever caused crime?

The Trump era is hardly the first eruption of anti-immigrant sentiment in the U.S. history. But prior waves of nativism also failed to substantiate the link between immigrants and criminality. Herbert Hoover appointed the Wickersham Commission in 1929 to do an audit of American crime and justice during Prohibition and specifically analyzed the criminality of the foreign-born population in one section. The committee concluded that immigrants were no more likely to commit crimes than native-born counterparts, and that deporting them all would not have no significant effect on the share of criminals in the country. Immigrants “can be definitely exonerated from the charge that they are responsible for a disproportionate share of the crimes current in this country,” the report read.

Do “sanctuary cities” see spikes in crime?

The term “sanctuary city” is a misleading name often given to cities that limit how their police and local institutions cooperate in federal immigration enforcement, through a range of policies. It’s often used by opponents of these policies to suggest that these cities offer free rein to law-flouting immigrants. Incidents like the 2015 murder of a young woman named Kathryn Steinle in San Francisco are frequently invoked to argue that sanctuary policies embolden perpetrators. (An undocumented Mexican immigrant was arrested for the shooting and acquitted in 2017.)

But the evidence doesn’t support that either. In a recent study published in the journal Urban Affairs Review, researchers analyzed crime data in two ways and found that, first, crime did not increase in cities after they put in place sanctuary policies, and second, that these policies had no effect on the rates of violent crime, property crime, and rape in sanctuary cities compared to others. The authors concluded:

The argument advanced by some politicians that immigration—namely, “illegal” immigration—is somehow linked to crime in any sort of meaningful way is simply not true.

Three other studies have come to similar conclusions regarding sanctuary policies.

Human migration is a complicated phenomenon. When someone leaves their home, they may not be thinking about what lies ahead—they just need to get themselves and their loved ones out of dangerous or untenable circumstances. They are seeking a place where they can find work, connections, family, and community. For many people, that place is still America—and those connections were established long ago. The kind of punitive measures and policies that President Trump claims a moral duty to enact are not likely to discourage migrants, experts say; they promise only to worsen their suffering.