Can U.S. Immigration and Customs Enforcement legally detain a U.S. citizen during a protest?

1. When ICE Can and Cannot Detain Citizens — Law vs. Practice

Federal immigration law and ICE’s civil enforcement mandate do not permit detaining a U.S. citizen on the basis of immigration status, and legal experts say ICE lacks civil authority to arrest citizens for immigration violations; however, agents retain the authority to arrest anyone, regardless of status, for federal crimes when they have reasonable grounds or probable cause to believe a felony has been committed. Investigations and reporting show that in practice ICE and other federal agents have detained citizens at protests when asserting criminal grounds, but reporters and lawyers note ambiguity about whether probable cause existed in many incidents and raise concerns that civil enforcement posture or pressure to meet deportation metrics may have influenced aggressive tactics ^{[1] [5]}.

2. How Often and How Long Citizens Have Been Held — Numbers and Gaps

A ProPublica investigation compiled evidence of more than 170 U.S. citizens held by immigration agents, with many detained for days and reporting obstacles to contacting lawyers and family; other local reporting documents concentrated clusters of citizen detentions at specific protests, including at least 38 arrests in Los Angeles and first‑time detentions in San Francisco. These findings underscore that the government does not centrally track how often immigration agents hold Americans, creating a data gap that complicates oversight, legal redress, and public understanding of whether detentions were lawful or systemic ^{[2] [1] [3]}.

3. Allegations of Mistreatment and Constitutional Risk

Victims and watchdog reporting allege physical mistreatment — including being kicked, dragged, and held without prompt access to counsel — and instances where citizens were detained despite presenting identification, such as REAL ID, or service records. These accounts raise constitutional red flags including potential Fourth Amendment seizure claims and Fifth Amendment due process concerns; investigative reporting documents multiple cases where the factual basis for detention appears shaky, amplifying questions about training, identification practices, and accountability for agents who detain U.S. citizens in protest settings ^{[3] [4] [2]}.

4. Policy Drivers: Enforcement Targets, Sensitive‑area Policies, and Protest Policing

Reporting links the uptick in aggressive federal tactics to policy choices and enforcement priorities: pressure to increase arrests and deportations, and the rollback of prior guidance limiting enforcement in “sensitive” locations, have coincided with heightened confrontations at demonstrations. Experts and advocates argue these shifts create incentives that may blur lines between civil immigration enforcement and crowd‑control or criminal enforcement roles at protests, while ICE and federal agents operate under competing mandates that complicate lawful engagement with demonstrators ^{[5] [6]}.

5. What This Means for Protesters and Oversight — Practical and Legal Implications

For protesters, the practical implication is that a U.S. citizen can be detained by immigration agents only under asserted criminal authority, but real‑world practices show risk of mistaken detention, delayed legal access, and difficulty obtaining remedies because the government lacks transparent tracking and accountability systems. For policymakers and courts, the documented incidents create pressure to clarify statutory limits, tighten identification and arrest protocols, restore or codify sensitive‑area protections, and improve oversight so that constitutional safeguards are meaningfully enforced and citizens wrongfully detained have clearer paths to redress ^{[1] [2] [7]}.