In early 2025, in an effort to facilitate its deportation goals, the Trump administration entered into hundreds of agreements with local police departments to essentially deputize them to act as federal immigration agents.

The bulk of these agreements were signed in Republican strongholds such as Texas and Florida, places where the immigration policies of state leaders aligned with those of the Trump administration.

But as Trump ramped up his deportation efforts over the course of 2025, how would immigration enforcement play out in sanctuary cities and states?

Sanctuary policies aim to focus local policing on community safety rather than immigration enforcement. In 2016, there were approximately 340 of these sanctuary jurisdictions in the U.S. By the start of Trump’s second term, there were just over 1,000 of them

Would local police in sanctuary cities and states step in to protect someone they knew hadn’t committed a felony or was a citizen? Would officers in these places admonish ICE agents for failing to follow proper protocol?

Instead, over the course of 2025, videos from sanctuary jurisdictions – including Chicago, California and Worcester, Massachusetts – showed local police acting more like auxiliary enforcers.

In Peter Mancina’s forthcoming book “On the Side of ICE: Policing Immigrants in a Sanctuary State,” he explores the cultural, bureaucratic and political roadblocks to enacting immigrant-friendly policing reforms, with a focus on New Jersey, where Mancina works as an adjunct law professor at Rutgers University.

In an interview, edited for length and clarity, Mancina explains why sanctuary policies don’t necessarily change what happens on the ground.

The adoption of sanctuary policies grew dramatically during the first Trump administration. Yet at various points in the book, you call them a “rebrand,” a “public relations facade” and “immigration enforcement assistance with an immigrant friendly face.” What’s behind those characterizations?

There’s an internal tension to sanctuary policies. There’s this broader sanctuary movement that’s been around since roughly 1980, which came about largely in response to U.S. involvement in Central American civil wars and protecting immigrants fleeing these and other conflicts.

The activists started working with city officials sympathetic to their cause in cities such as San Francisco to create resolutions protecting immigrants that were largely symbolic. After the San Francisco Police Department was found to be ignoring the resolution, the city created the country’s first sanctuary ordinance in 1989. With this ordinance, activists hoped that local police could be prevented from collaborating with federal immigration officers.

But many activists assumed that the kind of ethics and the values that existed in the sanctuary movement could actually be taken up in policy and implemented, because there’s this notion that when you pass a law or ordinance it will be implemented as written.

A major part of the book is to say, “Actually, that’s not how policy works.” It fits within these bureaucratic cultures. And in policing culture, there’s already this web of relationships that local cops have with federal agents, and these cultures have their own value systems. Something that people don’t really talk about is that local police aren’t just used by ICE as these local enforcers of immigration law. In fact, a lot of times local law enforcement look to ICE as........

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