One of President Trump’s executive orders will reestablish Secure Communities (SCOMM), which was the most effective interior immigration enforcement program in decades. It was started during the Bush administration and rapidly expanded under Obama, eventually covering virtually all counties in the United States. It worked by checking the fingerprints of local and state arrestees against federal immigration and criminal databases. If Immigration and Customs Enforcement (ICE) suspected the arrestee of being an illegal immigrant they would issue a detainer to hold the arrestee until ICE could pick them up. The Obama administration ended SCOMM in 2014 and replaced it with the similar Priority Enforcement Program.

SCOMM was certainly effective at apprehending and deporting illegal immigrants but it did not make communities more secure from actual criminals. SCOMM was not rolled out nationwide all at once, but rather incrementally (by county) over a four year period of time, in a way unrelated to local crime rates. Social scientists were able to exploit this quirk of SCOMM’s implementation to see if it had an effect on local crime rates, which it would if illegal immigrants were more or less likely to commit violent or property crimes. To make communities more secure, SCOMM would have to have lowered local crime rates.

In a paper published in the prestigious Journal of Law and Economics, Thomas J. Miles and Adam B. Cox found that SCOMM had no effect on local crime rates. Elina Treyger, Aaron Chalfin, and Charles Loeffler similarly found that SCOMM had no effect on local crime rates. Their findings suggest several things. One, SCOMM did not make communities more secure from crime. Two, illegal immigrants are less crime-prone than many people think and probably have about the same level of criminality as natives. Three, a community’s cooperation with the federal government in enforcing immigration law doesn’t seem to raise crime rates (some people suggest that such cooperation makes policing less effective).

Secure Communities is an immigration enforcement strategy that was very effective at identifying and removing illegal immigrants. Many states, like California, will not cooperate with the federal government in this reiteration of SCOMM, so it will likely be less effective than before. However, SCOMM supporters cannot claim that the program makes communities more secure by reducing the amount of violent or property crime.