How have court decisions and federal oversight influenced ICE detainer use across both administrations?
Executive summary
Court decisions and federal oversight have reshaped how ICE uses immigration detainers by constraining legal authority, altering local compliance, and prompting administrative rule changes that produced measurable swings in detainer issuance under successive administrations [1] [2]. Judicial rulings that scrutinize Fourth Amendment implications, combined with fluctuating federal oversight—strengthened guidance under Biden and staffing/oversight cuts under Trump 2.0—help explain the drop in detainer use early in the Biden term and its sharp rebound after 2025 [3] [2] [4].
1. Courts forced scrutiny of detainers and seeded local resistance
Federal appellate courts have repeatedly held that ICE detainers can raise Fourth Amendment problems when they lack independent probable-cause determinations, and those rulings have underpinned local “sanctuary” policies that bar compliance with detainer requests [1]. That jurisprudence created a legal environment where local law enforcement agencies grew wary of honoring detainers without judicial or prosecutorial review, feeding a decline in effective detainer outcomes even when ICE issued them [1] [2].
2. Biden-era guidance, courtroom fights, and reduced detainer volumes
The Biden administration adopted enforcement guidance that narrowed the universe of cases for interior arrests and detentions, and that policy produced an abrupt fall in monthly detainer issuance compared with the Trump period, according to TRAC’s records [2]. Those Mayorkas-era priorities were nevertheless contested in court by states seeking to compel stricter enforcement, prompting the Justice Department to defend the administration’s discretion in litigation up to the Supreme Court level, a fight that highlights how judicial review became central to detainer policy debates [3].
3. Data show detainers fell but compliance tracking remained weak
TRAC’s analysis found a sharp drop in detainers when Biden took office and noted that ICE historically issued far more detainers than the number of people it actually took into custody, while the agency does not reliably track how many local agencies honor or refuse detainers—leaving a data gap that courts and policymakers have had to interpret without full transparency [2]. That empirical opacity has made it difficult to separate legal effects (court rulings) from administrative priorities when assessing detainer outcomes [2].
4. Trump 2.0 reversed priorities; oversight cuts altered accountability
The second Trump administration moved quickly to rescind Biden-era limits on enforcement in “protected areas” and to expand detentions and arrests, producing a rapid rise in detainer issuance and ICE’s detainee population—some reporting shows detentions and detainer use climbed sharply after January 2025 [5] [6] [7]. At the same time, Reuters documented cuts to DHS oversight, including placing oversight staff on leave and resisting body-camera programs, undermining internal accountability even as detainer use surged—an oversight dynamic with clear implications for how detainers are issued and monitored [4].
5. Competing narratives: targeting criminals vs. mass enforcement
Advocates of stricter detainer use point to TRAC’s finding that many detainers during the Biden years were served against people with criminal charges or convictions and argue detainers are a targeted public-safety tool [8]. Critics, including immigrant-rights groups and analyses of Trump-era policy, argue that expanded detainer use under Trump becomes part of broader aggressive enforcement that deters cooperation with local authorities and sweeps in noncriminal immigration violators [9] [6]. Courts have been the arbiter of the legal limits of detainers even as federal policy alternately tightened or relaxed their use.
6. The legal-oversight feedback loop that will decide future use
Judicial rulings constraining detainer practices and local noncompliance built momentum for administrative guidance in the Biden years and created legal pressure points that states sought to exploit when they wanted stricter enforcement [1] [3]. Conversely, when federal oversight was pared back and enforcement directives changed under Trump 2.0, detainer issuance rebounded, demonstrating a clear feedback loop: courts and local policies shape federal choices, and shifts in federal oversight and enforcement priorities then change detainer volumes and local calculus [4] [2] [6]. Where data remain thin—particularly on how many detainers are honored—judicial review and oversight will continue to be decisive in shaping practice [2].