Under what legal authorities can ICE detain immigrants without criminal convictions?
Executive summary
ICE (DHS) detains noncitizens under multiple provisions of the Immigration and Nationality Act (INA): discretionary detention pending removal under INA §236(a) and several mandatory-detention rules for particular classes of noncitizens; Congress has authorized broad detention authority while courts have imposed some constitutional limits [1] [2]. In practice, ICE’s Enforcement and Removal Operations runs a civil detention system that holds large numbers without criminal convictions—studies and ICE data report many detainees lack criminal records and ICE publishes detention standards and management guidance for those held [3] [4] [5].
1. How the law draws the line: statutory authorities that enable detention
The core statutory framework is the Immigration and Nationality Act: INA §236(a) authorizes discretionary arrest and detention of an alien pending a decision on removal, while other INA provisions impose mandatory detention for certain categories (for example, some criminal or national-security cases); Congress thus “authorizes—and in some cases requires—the Department of Homeland Security to detain non‑U.S. nationals” [1] [6]. The Congressional Research Service and related legal overviews describe detention as a multifaceted scheme that depends on admission status, alleged conduct, and whether a final removal order exists [1] [2].
2. Civil not criminal — and what that means for people without convictions
Immigration detention is civil in nature, not criminal, meaning many constitutional protections that apply in criminal proceedings differ and detainees are not guaranteed government‑appointed counsel; courts nevertheless have shaped limits, holding detention must be “reasonably necessary to secure removal” and raising constitutional concerns about indefinite confinement [2] [6]. Multiple policy analyses and advocacy reports document that a large share of those in ICE custody have no criminal conviction—recent reporting and research find a majority of detainees lack criminal records, underscoring that statutory detention power often applies to people without criminal convictions [5] [3].
3. Administrative practice: how ICE implements statutory authority
ICE’s Enforcement and Removal Operations (ERO) manages detention nationwide and relies on statutory authority to arrest, detain and remove aliens “who may present threats” or are otherwise removable; the agency issues detention standards (National Detention Standards / PBNDS) and operational guidance to govern how facilities operate and whom to hold [4] [7]. ICE’s public statistics and dashboards show the agency’s approach combines interior arrests, transfers from CBP, and use of alternatives to detention—but the agency’s written standards and facility lists make clear ERO is the day‑to‑day custodian under the INA regime [3] [8].
4. Delegations and local partnerships that expand detention reach
Federal detention authority is amplified by programs that deputize or partner with state and local actors: Section 287(g) lets ICE delegate certain immigration functions to local law enforcement, and warrants/agreements can produce detentions that begin in local jails before transfer to ICE custody [9]. Reporting shows these collaborations channel people into civil immigration custody who may never face criminal conviction at the federal level [9] [10].
5. Recent policy shifts and litigation that affect who gets detained
Analysts report policy changes since 2025 have broadened who ICE deems subject to mandatory detention, prompting litigation and mixed judicial responses: some administrative memos and ICE policy directives have expanded categories of removable noncitizens, which courts in some cases have upheld and in others rejected [5]. The Congressional and legal literature stresses that statutory expansions meet constitutional scrutiny in the courts, especially where detention is prolonged [2].
6. Oversight, standards and reported gaps
ICE publishes detention standards and facility lists, and DHS components are charged with oversight, but civil‑society and legal groups document recurring problems—inspection, conditions, and the use of detention for noncriminal populations remain contested [11] [4] [12]. The National Detention Standards and revisions are agency guidance; they do not change the statutory basis for detention but shape conditions and review processes inside custody [7] [11].
7. What the sources do and do not say
Available sources explain the statutory architecture (INA §§ discussed by CRS and policy primers), ICE’s operational role and standards, delegation programs like 287(g), and that many detainees lack criminal convictions [1] [2] [4] [9] [5]. Available sources do not mention a single, novel statutory authority beyond the INA framework or provide exhaustive lists of every INA subsection applied in every case—those specifics are in case files and agency memos not reproduced here (not found in current reporting).
Limitations: this analysis relies on public ICE documents, government legal primers, policy research and investigative reporting provided in the search results; statutory interpretation and case‑specific outcomes vary in litigation and administrative guidance beyond the excerpts cited [1] [2] [5].