On his first day in office, President Biden immediately began to roll back many Trump administration policies that had restricted immigration and targeted the approximately 10.5 million undocumented immigrants in the United States. That included issuing a 100-day moratorium on most deportations, which was immediately challenged in court, and revoking Trump’s Executive Order No. 13768, “Enhancing Public Safety in the Interior of the United States.”

Originally issued just days after Trump assumed office in 2017, E.O. 13768 had expanded the criteria for deportation and also expanded cooperation between Immigration and Customs Enforcement (ICE) and local law enforcement.

But did it actually “enhance public safety,” as its title would have it?

Advocates and scholars have long argued that deputizing local police to conduct immigration enforcement has a “chilling effect” on undocumented immigrants and their communities, reducing their willingness to use health care and social safety-net programs. Our recently published research finds that such cooperation also deters both undocumented immigrants and the Latino communities in which they often live from reporting crime, particularly since an estimated 76 percent of undocumented immigrants are from Mexico, Central America, the Caribbean and South America.

With such policies potentially affecting at least 18.4 percent of the U.S. population that is Latino, as well as both Latino and non-Latino undocumented immigrants, here’s how cooperation between federal immigration enforcement and local police negatively affects public health and safety.

The effect of immigration enforcement

Trump’s 2017 immigration policy changes included expanding the number of local jurisdictions signing 287(g) agreements, based on section 287(g) of the Immigration and Nationality Act, which deputize local police to enforce immigration laws. Trump also reinstituted the Secure Communities program — started under George W. Bush in 2008 and first expanded and then dismantled under Barack Obama in 2014 — which alerted the Department of Homeland Security when police arrested an undocumented immigrant. Finally, Trump threatened to punish any “sanctuary jurisdiction,” meaning any towns, cities, counties or states that declared they would limit official cooperation with ICE. A 2017 survey of law enforcement and court officials by the ACLU and the National Immigrant Women’s Advocacy Project found that police had increasing difficulties investigating crimes, as immigrant communities feared any contact with law enforcement.

We conducted our research in two parts. First we looked at county-level FBI and census data from 2016 and 2017. There we found that once the agreements went into effect, residents reported less crime in the counties coded as having higher shares of Hispanic people and in counties where police cooperated more with ICE. We compared these lower report rates with National Crime Victimization Survey (NCVS) data, a nationally representative survey of households that collects data on crime victimization.

In 2017, we found, Hispanic survey respondents were 12 percent less likely than non-Hispanic respondents to report crime victimization to the police. This pattern suggests that while crime victimization itself wasn’t changing, communities’ willingness to report victimization was.

We found that this pattern held under both Republican and Democratic administrations by also studying the effect of the Secure Communities program. We used the phased rollout of the program to compare crime rates in counties before and after the program was implemented. As the intensity of enforcement increased, the reported crime rate decreased.

Our findings are consistent with those of other recent work. For example, political scientist Tom K. Wong and co-authors find that undocumented immigrants were less likely to trust law enforcement officers who cooperate with ICE. Similarly, economists Catalina Amuedo-Dorantes and Esther Arenas-Arroyo find in a working paper that as immigration enforcement intensified, fewer immigrant women sought protection from domestic violence by petitioning for legal status under the Violence Against Women Act.

Meanwhile, scholars have found that when the risk of deportation goes up, undocumented immigrants and their relatives are less likely to apply for the Supplemental Nutrition Assistance Program (SNAP), to rely on Medicaid for health care, or to seek help from the Women, Infants and Children Program (WIC). Economists Amanda M. Grittner and Matthew S. Johnson’s working paper finds that when local immigration enforcement intensifies, workers in higher Hispanic-share work sites have more injuries but file fewer labor complaints. Rather than promoting public health and safety, such policies only further marginalized both undocumented immigrants and their communities.

Local policies matter

All this varies by whether local governments cooperate with ICE. We used data from the Immigrant Legal Resource Center (ILRC), which maps which localities cooperate with ICE. We found that in counties that did not cooperate with ICE, crime reporting didn’t drop the way it did in counties actively cooperating with ICE.

This too is consistent with work from other scholars, such as Ricardo D. Martínez-Schuldt and Daniel E. Martínez’s recent article and Loren Collingwood and Benjamin Gonzalez O’Brien’s 2019 book. Both find that sanctuary policies make Latino communities more willing to report crime — while immigration enforcement cooperation with police reduces willingness to report. Rather than promoting public health and safety, therefore, active cooperation between local authorities and ICE only further marginalizes both undocumented immigrants and their communities.

Will local governments cooperate with ICE in the future?

Latino and undocumented communities have been hit especially hard by the coronavirus pandemic, in part because of anti-immigrant policies and structural racism. Ours and others’ research further corroborates that policies that link ICE with local law enforcement have reduced undocumented and Latino communities’ willingness to use public services. As a result, these policies directly undermine the health and safety of both the approximately 10.5 million undocumented immigrants in the United States and their broader communities.

In the final days of Donald Trump’s presidency, the Department of Homeland Security (DHS) attempted to lock the Biden administration into its immigration policies by signing agreements with numerous state and county jurisdictions to require six months’ notice for any immigration enforcement changes. Based on these agreements, the state of Texas has already sued to stop the Biden administration from enforcing a 100-day deportation moratorium, with a judge placing an injunction on the order. If the Biden administration wishes to keep immigrants and Latino communities protected from crime, illness, child hunger and other such public health dangers, it may wish to show how the previous administration’s immigration policies undermined those goals.

Reva Dhingra @Reva_D is a PhD candidate in government at Harvard University researching migration and international aid.

Mitchell Kilborn is a PhD candidate in government at Harvard University studying American politics.

Olivia Woldemikael @owoldemik is a PhD candidate in government at Harvard University studying comparative politics and migration.