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How do sanctuary states and cities impact the number of ICE arrests?
Executive summary
Research shows sanctuary policies tend to reduce how often local jails honor ICE detainer requests and are associated with fewer deportations, while most empirical studies find no measurable increase in crime tied to those policies [1] [2]. Federal agencies and conservative outlets emphasize large ICE operations and spikes in detainer requests or arrests in sanctuary jurisdictions — framing policies as impediments to enforcement — but reporting and academic work both note ICE can and does arrest people in sanctuary cities independently, often shifting arrests from jails to the community [3] [4] [1] [5].
1. What “sanctuary” policies actually do — and what they don’t
Sanctuary policies are a patchwork of local, county and state rules that limit cooperation with federal immigration enforcement: they can bar honoring ICE detainers, prohibit 287(g) deputizations, or restrict local inquiry into immigration status — but they do not stop ICE from conducting its own arrests in the community [2] [6] [5]. The Vera Institute and American Immigration Council explain these policies are designed to prevent local resources from being used for civil immigration enforcement, while preserving the ability to arrest and prosecute criminal offenses [7] [2].
2. The academic record: fewer detainer honors, no rise in crime
Peer-reviewed research finds sanctuary policies reduced the rate at which ICE detainer requests resulted in arrests and led ICE to issue fewer detainer requests, yet these policies produced no detectable increase in crime rates [1]. The National Academy of Sciences–style analysis cited by the American Immigration Council and the PNAS paper concluded that sanctuary policies “reduced deportations” without threatening public safety [2] [1].
3. Why ICE and federal officials say arrests rise in sanctuary places
ICE and DHS releases highlight large arrest tallies and spikes in detainer requests in targeted jurisdictions — for example, DHS claimed over 6,000 detainer requests in New York City and ICE press releases describe multi‑city operations resulting in dozens or hundreds of arrests [3] [4] [8]. These communications serve two purposes: they document enforcement actions and buttress a policy argument that sanctuary rules complicate federal operations and force ICE to expend more resources to find and arrest people outside jails [4] [3].
4. Reconciling apparent contradictions: same activity, different pathways
The data can look contradictory because sanctuary policies change where and how ICE apprehends people more than whether ICE can apprehend them. Academics and reporters note most deportation arrests come from fingerprint matches generated when local jails share booking data; when jails won’t hold people on detainers, ICE often must make arrests in the community — which can raise the number of publicly visible operations but does not necessarily mean fewer total ICE arrests overall [1] [9]. Stateline summarizes this tradeoff: sanctuary rules may reduce deportations in aggregate but often don’t prevent ICE from ultimately making arrests [9].
5. Numbers and messaging: how context changes the headline
Different actors present counts selectively. ICE or DHS statements emphasize arrests or detainer‑request spikes to argue sanctuary policies impede enforcement [3] [4]. Local advocates and researchers point to studies showing reduced deportations and no uptick in crime [1] [2] [7]. Some outlets compile operation totals (e.g., “538 arrests” or “over 1,400 arrested in three weeks”) without the methodological detail needed to compare apples to apples, such as whether arrests stemmed from criminal convictions, administrative removals, or prior detainer matches [8] [10]. Available sources do not provide a consistent nationwide time‑series that attributes changes in total ICE arrests directly to sanctuary laws.
6. Limitations, disagreements and open questions
Scholars warn against overinterpreting either side: some reports find “suggestive” evidence sanctuary policies reduce deportations but caution about large effects, while federal releases stress operational impacts without peer‑reviewed context [9] [3]. The academic record focuses on measurable outcomes like detainer success rates and local crime; federal and advocacy communications focus on arrests and public safety narratives. Not found in current reporting is a single, up‑to‑date national dataset in these sources that isolates how sanctuary policies changed total ICE arrests across all jurisdictions after 2015 while controlling for enforcement priorities and resource changes.
7. Bottom line for readers
If your question is whether sanctuary policies make it impossible for ICE to arrest people in those places, the answer in the reporting is no — ICE still conducts arrests and has staged large operations in sanctuary cities [4] [8]. If your question is whether sanctuary policies meaningfully increase crime or eliminate federal enforcement, peer‑reviewed studies and policy analyses say they reduce detainer‑based transfers and deportations without increasing crime [1] [2]. Both interpretations are used in advocacy and political messaging; read ICE and DHS tallies alongside peer‑reviewed research to see how enforcement pathways — not always net arrest counts — change depending on local cooperation [3] [1].