In the United States, local law enforcement agencies are legally and organizationally independent entities from federal law enforcement agencies like the FBI and ICE. While local police enforce local, state and federal laws, they are not required to enforce civil immigration laws. On the Side of ICE: Policing Immigrants in a Sanctuary State (NYU Press, 2025) examines the role of local police as voluntary, auxiliary reinforcements for ICE, focusing on the police force in New Jersey. It argues that even police in sanctuary jurisdictions, which explicitly label themselves as immigrant-friendly, are nonetheless still informally multiplying ICE’s forces through voluntary cooperation. While to date, the ethnography of policing has been produced from participant observation with the police in “ride-alongs” during patrol work and in jails and the examination of official documents like police reports, this book employs a novel method of transcribing police body worn camera (BWC) video footage to provide immersive, ethnographic thick description narratives of instances of local police officers assisting ICE. It makes the case that BWC ethnographic methods are better able to capture realistic interactions between the police and those they stop than when participant observers are on the scene. The volume thus not only reveals the ways in which local police function to assist ICE in enforcing federal civil immigration law, but also demonstrates the significance of using BWC-based ethnographies to examine how police exercise power. From police footage, internal records, and other materials, On the Side of ICE renders intimate, on-the-ground ethnographic narratives that illuminate what policing immigration looks like in contemporary America.