Retributive Enforcement and Uncooperative Federalism: Did ICE Target Sanctuary Jurisdictions?

During the growth of ICE’s Secure Communities (S-Comm) program, many communities adopted so-called “sanctuary” policies, limiting cooperation to enforce federal immigration policies. In response, ICE and the first Trump administration declared that federal agents would “end” sanctuary communities. This study investigates the relationship between federal immigration enforcement and local policies. We assess whether ICE increased its direct enforcement activities (known as “community arrests”) in communities with anti-detainer policies, examining enforcement through fiscal years 2015–2018, over both the Obama and Trump administrations. We find that ICE significantly increased community arrests in these communities; however, communities with anti-detainer policies still maintained lower overall arrest levels, despite being targeted directly. These findings demonstrate that local governments can meaningfully constrain federal enforcement capacity in our fragmented federalist system—even over issues like immigration, in which the federal government maintains supremacy.