Throughout his 2016 presidential campaign, Donald J. Trump routinely described so-called sanctuary cities as posing a threat to public safety by harboring “criminal aliens.” He also characterized immigrants—particularly unauthorized Mexican immigrants—as criminals.
This xenophobic and anti-immigrant discourse resonated with a segment of voters and helped propel Trump into the White House.
Sanctuary ordinances are passed by cities to prohibit city employees from cooperating with the enforcement of Federal immigration law. In January 2017, President Trump signed Executive Order 13768, which withholds certain federal grants from sanctuary jurisdictions until they fully cooperate with the Federal government in the enforcement of immigration law (see Section 9(a)). In November 2017, a Federal judge found Section 9(a) of the executive order unconstitutional and issued a permanent injunction on its nationwide implementation.
According to several recent studies, there is no evidence that the implementation of sanctuary policies leads to violent crime.
Our analysis of violent crime in 107 cities contributes to this growing body of research. We found cities that adopt sanctuary ordinances experience a decrease in robberies. Moreover, among sanctuary cities, an increase in the relative concentration of unauthorized Mexican immigrants leads to a reduction in homicides. These results are contrary to the prevailing political discourse.
Trump’s political rhetoric and policy decisions raised several important questions that we addressed in our research. First, what exactly is a sanctuary policy? Second, does the implementation of such an ordinance in any way affect crime? Finally, is unauthorized immigration associated with increased crime?