As part of his justification for tightening U.S. immigration, former president Trump often went on about the criminality and violence of undocumented immigrants. During his first campaign, he went as far as saying that Mexican immigrants were "…bringing drugs. They're bringing crime. They're rapists.” This statement was met with significant reproach—and with reason. Trump had absolutely no factual basis to substantiate such inflammatory claims. Nonetheless, his immigration-reducing approach included a thirty percent increase in arrest rates by Immigration and Customs Enforcement (ICE) in 2017 as well as a twelve-year high in the number of people apprehended at the U.S.-Mexico border in 2019. 

As Scientific American reports, “Some of the most solid evidence to date shows that President Trump's cornerstone immigration policy was built on a wholly false premise.” In fact, we have new evidence that fully corroborates the opposite to be true: undocumented immigrants are far less likely to commit crimes in this country than are U.S. citizens and naturalized immigrants.  “Simply put, we found that undocumented immigrants have lower felony arrest rates than both legal immigrants and, especially, native-born U.S. citizens,” says University of Wisconsin-Madison sociologist Michael Light, a co-author of the study.  This finding is the result of a study  published by the Proceedings of the National Academy of Sciences in December 2020.  

As its title suggests, “Comparing crime rates between undocumented immigrants, legal immigrants, and native-born US citizens in Texas” examines “uniquely comprehensive arrest data from the Texas Department of Public Safety to compare the criminality of undocumented immigrants to legal immigrants and native-born US citizens between 2012 and 2018.” This is the first time that researchers have been able to link specific immigration status to the rates for specific types of crimes; information on immigration status is remarkably scarce in most crime databases. Texas, however, proves to be an exception: it is the only state in the country to require “the determination and documentation of immigration status as part of its standard criminal justice records practice.” As a result of this, researchers were able to use this data to compare criminality between undocumented immigrants, legal immigrants, and native-born citizens.

Four crime types were considered: violent, property, drug, and traffic arrests.  Undocumented immigrants have the lowest felony arrest rates across all four crime types.  U.S.-born citizens are actually 2 times more likely to be arrested for violent crimes, 2.5 times more likely to be arrested for drug crimes, and over 4 times more likely to be arrested for property crimes.  Additionally, the relative contribution of undocumented immigrants to drug crime rate appears to be decreasing. This trend holds true for legal immigrants, who had a slightly lower rate of felony drug arrests in 2012 compared to U.S.-born citizens. By 2018, this gap has widened due to an increase in drug crime among native-born citizens.  In order to ensure that these findings were sound, investigators repeated their analysis with subtle shifts in the data: “using convictions instead of arrests, misdemeanors in addition to felonies, size estimates of undocumented immigrant populations from both the Pew Research Center and the Center for Migration Studies.”  Even with these alterations, the crime rates for undocumented immigrants remained appreciably lower.

Undocumented immigrants clearly pose no unique criminal threat or risk.  These results clearly undermine claims like those made by Trump.  They also provide an explanation why, for example, crime rate has not changed despite increased deportation. As University of Wisconsin-Madison News states, the federal government's Secure Communities Program mandates “sharing information on immigration status and is pitched as a way to deport criminals before they can commit more crimes in the United States.” ICE receives notice through Secure Communities when a non-citizen is arrested. Despite deporting over 200,000 people in its first four years, Secure Communities had no influence on crime rates.  On this, Light remarks, “The population of people we deported simply were not a unique criminal risk. Removing them isn't going to make you all that safer.”

Returning to the results, it is natural to consider why the crime rates are lower for undocumented immigrants. There are several possible reasons, suggest the researchers. One such reason is Assimilation Theory, which posits that immigrants arriving to a new country aim to assimilate into their new communities and adhere to all of its customs, rules and regulations. Another reason may be that undocumented individuals who come to the United States are often defined by “qualities such as motivation to work and ambition to achieve, attributes that are unlikely to predispose them toward criminality.” And perhaps most obvious of all: fear of deportation. Undocumented immigrants, of course, face much harsher consequences for criminal acts compared to their citizen and legal immigrant counterparts. 

These three reasons—assimilation, selection, and deterrence—offer an understanding of why the crime rates are considerably lower for this unfairly targeted population.  Whatever the ultimate reasons are, the solidity of the findings will be undoubtedly useful in immigration policymaking. This is especially so under the administration of President Biden, who has promised from the beginning of his campaign to usher in a new era of positive immigration reform.