A growth in the undocumented immigrant population is not associated with an increase in local crime, according to a new study from The Marshall Project. The findings directly contradict one of the president’s favorite talking points about immigrants and crime.

This study, which focuses squarely on undocumented immigrants, uses local crime rates published by the FBI and concluded that between 2007 and 2016, almost every type of crime had a flat line trend, suggesting that any increase in undocumented immigrants has had no effect on crime. Areas with higher rates of illegal immigration actually appeared to have a slight drop in the crime rate.

Studies on undocumented immigrants are relatively rare, in part because it’s hard to collect data on them. While it is difficult to estimate the exact number of undocumented immigrants in the United States, the most recent available data from the Department of Homeland Security (DHS) is from 2016 and puts the population roughly at 10.7 million, down a million and a half from 2007.

The study used Pew Research data on undocumented immigrants in various metropolitan areas, and looked at FBI data on violent crimes and property crimes, including assault, robbery, murder, burglary, and larceny. The majority of the areas had a decrease in both violent and property crime, which the researches note is “consistent with a quarter-century decline in crime across the United States.”


The study fits into a broader body of research, which has found that immigrants — both undocumented and documented — are less likely to be incarcerated and that undocumented immigration did not increase violent crime, but was rather associated with a slight decrease. These findings are consistent with a study published in Criminology, an academic journal, which concluded that undocumented immigration is associated with a decrease in crime, and one conducted by the libertarian Cato Institute, which found that undocumented immigrants are less likely to be incarcerated. The idea that immigrants, both undocumented and documented alike, don’t commit crimes at a rate any higher than native-born Americans should not be surprising, given that almost any criminal infraction can result in their deportation. Their future in the United States quite literally hinges on not committing a crime. Even a routine traffic stop can turn into a deportation case for an undocumented individual.

The false argument that all undocumented immigrants are rampant criminals has been used by the Trump administration to further weaponize the government’s immigration enforcement agencies.

When presented with the results of studies like that of The Marshall Project in the past, Trump has pointed to the immigrant population of federal prisons.

“You don’t really believe that stat, do you? Do you really believe that stat?” Trump told CNN reporter Jim Acosta in February, “Take a look at our federal prisons.”

According to federal data as of December 31, 2017, 17% of the people incarcerated in the federal prison system were confirmed to be undocumented, but that data is misleading. State and local prisons account for 90% of the U.S. prison population. According to an independent estimate based on Census Bureau data in 2016, undocumented immigrants make up approximately 6% of inmates at the federal, state, and local level.


This false narrative has been also used by Trump to justify the national emergency declaration, stating that there is an “invasion” of “all types of criminals and gangs.” He has used it to threaten sanctuary cities, jurisdictions where local police are prohibited from collaborating with federal immigration authorities, and claimed immigration laws like asylum are “dangerous.”

“Due to the fact that Democrats are unwilling to change our very dangerous immigration laws, we are indeed, as reported, giving strong considerations to placing Illegal Immigrants in Sanctuary Cities only,” Trump tweeted last month. “The Radical Left always seems to have an Open Borders, Open Arms policy – so this should make them very happy!”

Trump has routinely invited the families of American’s killed by undocumented immigrants to high-profile White House events, using their tragedies to call for strict immigration laws.

“Not one more American life should be lost because our nation failed to control its very dangerous border,” Trump said during his State of the Union address.

“Angel moms, angel dads, angel families; These are great people,” Trump said at a press conference weeks later, when he declared a national emergency at the border. “They’re fighting for their children that have been killed by people who were illegally in this country. And the press doesn’t cover them. They don’t want to. And they’re not treated the way they should be. They are fighting for other people because they don’t want what happened to their children or husband or anybody.”

Despite the overall drop in crime, arrests of non-criminal undocumented immigrants have skyrocketed, particularly under the Trump administration. In the first 14 months of the Trump administration, 58,010 undocumented immigrants without criminal convictions were arrested — a 203% increase compared to the final 14 months of the Obama administration.