What is the legal basis for local police to interfere with ICE arrests?
Executive summary
Local and state police generally do not have a blanket legal duty to assist ICE and ordinarily cannot lawfully stop federal immigration operations that are properly executed under federal authority; federal supremacy and immunity often shield ICE officers from state interference, but exceptions exist when federal agents exceed legal authority or act unlawfully [1] [2] [3]. States and localities can and do limit cooperation through sanctuary policies, 287(g) agreements can deputize local officers to perform immigration functions, and some states have passed laws that compel or criminalize local interference with federal enforcement [3] [2] [4].
1. Federal supremacy and when local police are generally out of the chain of command
The U.S. Constitution’s supremacy principle means immigration enforcement is a federal responsibility; when ICE agents act within their federal authority, state and local officers typically lack legal grounds to obstruct those actions and federal immunity can protect ICE from state prosecution [1]. Available sources do not present a statutory provision that requires routine local participation in ICE raids; indeed, fact-checking reporting finds no federal law mandating local police assist ICE [2].
2. The key statutory pathway that does allow local involvement: 287(g)
Congress created a mechanism — Section 287(g) of the Immigration and Nationality Act — that lets ICE delegate specific immigration functions to trained state and local officers under ICE supervision; jurisdictions enter memoranda of agreement to gain that authority, and ICE reports hundreds of such agreements nationwide [3]. Where a 287(g) agreement exists, local officers can lawfully perform immigration tasks and thus may lawfully assist or execute arrests aligned with ICE authority [3].
3. Sanctuary policies and the legal limits on local cooperation
Many cities and states have sanctuary-style policies that limit local cooperation with ICE (for example by refusing to honor detainers). Reporting notes sanctuary laws can prevent local officers from assisting ICE, and data shows local contacts — traffic stops, jail screenings — remain common pathways to ICE arrests even in jurisdictions trying to limit cooperation [5] [6]. A November 2024 Arizona ballot measure extended state authority in one state but that measure did not create a universal federal requirement for local assistance [2].
4. When local officers can arrest federal agents — and when they can’t
State lawmakers and local officials have argued that local officers may arrest federal agents who commit state crimes; reporting notes that if an ICE agent acts outside lawful federal authority or commits a state crime, state prosecution can proceed and a presidential pardon would not block state conviction [1]. At the same time, if an agent acts pursuant to federal authority, courts and doctrine of federal immunity can bar state interference — the line turns on whether the agent acted within federal duties or unlawfully [1].
5. New state laws and criminalizing “interference” with federal enforcement
Some recent state-level measures have gone the other way: reporting highlights new or proposed laws that make it a crime to “interfere, ignore, or thwart federal immigration enforcement efforts,” creating potential criminal exposure for neighborhood patrols or private citizens who try to intervene with ICE operations [4]. That legislative trend introduces direct legal risk for individuals who confront or obstruct federal agents even where local police decline to help [4].
6. How local practices still feed federal arrests despite formal limits
Practical cooperation occurs through numerous routine touches: traffic stops, jail booking screens, notification of detainers and informal information-sharing mean many ICE arrests begin with local policing even without formal agreements [5]. Courts and policies around protected spaces — such as courthouses — add another layer: ICE issued guidance limiting enforcement in protected areas, but that guidance does not eliminate interactions that originate from local custody or records [7] [5].
7. Competing perspectives and political context
Pro-enforcement officials argue federal operations are necessary to target criminal aliens and contend sanctuary policies obstruct public safety; data released in 2025 shows hundreds of thousands of ICE bookings, with debates over how many had criminal convictions [8] [9]. Civil‑liberties advocates point to analyses showing many people arrested lack criminal records and warn that local entanglement with ICE undermines trust in policing [9] [5]. Both camps influence legislation — from laws that compel local assistance to statutes that limit cooperation or criminalize private interference [2] [4].
8. What is not confirmed in the reporting
Available sources do not provide a single, across-the-board legal test for when any particular local officer may lawfully intervene in a specific ICE arrest; instead, legality depends on whether the federal actor is inside their authority, whether a 287(g) delegation exists, and on controlling state or local statutes and policies [1] [3] [2]. Sources do not offer exhaustive case law resolving all conflicts between state arrest powers and federal immunity in the context of ICE actions (not found in current reporting).
Bottom line: local police lack a blanket legal license to “interfere” with properly authorized ICE arrests, but statutory delegations (287(g)), state laws that compel cooperation, municipal sanctuary rules that limit it, and the factual question of whether an ICE agent acted unlawfully create a complex, case‑by‑case legal landscape [3] [2] [1] [4].