Jordan Gonzalez | Abogado de Inmigración EE.UU. — Madrid

Jordan provides a detailed analysis of Immigration and Customs Enforcement (ICE), examining the agency’s structure, history, legal authority, and oversight framework. He focuses on how ICE fits within the broader U.S. immigration system and why its design matters, particularly for international audiences seeking to understand American immigration enforcement beyond headlines.

Immigration and Customs Enforcement, commonly known as ICE, is one of the most misunderstood U.S. institutions. In many European systems, immigration is experienced primarily as an administrative function: residence permits, registration, work authorization, and social integration. In the United States, immigration law is also administrative, but it is enforced through a set of coercive tools that often resemble criminal law enforcement, even when no criminal conviction exists. ICE sits at the center of that tension.

United Sates immigration enforcement is not organized as a single “immigration ministry.” It is split across multiple agencies, governed by a mix of statutes, regulations, executive policy choices, and court doctrine, and implemented through a civil removal system that can still involve arrest, detention, transfer, and deportation. Understanding ICE therefore requires more than a simple definition. It requires understanding how the agency was created, how its internal parts function, what legal powers it has, and how those powers are (or are not) constrained.

The sections that follow do three things. First, they explain what ICE is and how it fits into the larger U.S. immigration apparatus. Second, they describe the core legal authorities that give ICE its practical leverage, especially detention and arrest authority within a civil system. Third, they outline current controversies that have made ICE a focal point for debates about transparency, oversight, constitutional limits, and institutional culture.

I. About the Agency

a. Generally

Immigration and Customs Enforcement (ICE) is a federal law enforcement agency within the U.S. Department of Homeland Security (DHS). It was created in 2003 as part of the sweeping post–September 11 reorganization of the federal government that dismantled the legacy Immigration and Naturalization Service (INS) and redistributed immigration-related functions across newly structured components.

That restructuring divided what had previously been a single immigration agency into three distinct institutional functions:

• Enforcement and investigations, assigned to ICE
• Border inspection and border patrol operations, assigned to U.S. Customs and Border Protection (CBP)
• Immigration benefits and adjudications, assigned to U.S. Citizenship and Immigration Services (USCIS)

This division is foundational. ICE is not “the immigration agency” in the sense of administering visas, residency, or naturalization. It does not grant immigration benefits. Its core mission is enforcement. That enforcement mission includes both civil immigration enforcement inside the United States and criminal investigations related to cross-border activity.

Understanding ICE therefore requires understanding that U.S. immigration governance is structurally fragmented. Administrative processing, border control, and interior enforcement are housed in separate agencies with distinct institutional cultures and statutory mandates. ICE occupies the enforcement end of that spectrum, which shapes both its legal authority and the controversies that surround it.

b. History

A key constitutional/structural rule is that immigration regulation is principally federal.

In Chy Lung v. Freeman (1876), the U.S. Supreme Court struck down a California scheme that effectively allowed the state to impose restraints on arriving noncitizens and warned that state action could entangle the United States in foreign-relations conflict. The decision became a canonical citation for the proposition that immigration admission rules are the exclusive domain of the federal government. This decision, in part, provides context for why in  modern enforcement actions, such as in Minneapolis, Los Angeles, and other targets for immigration enforcement, the State governments are limited in their ability to curtail ICE’s ability to operate within the jurisdiction, as they are preempted by the Federal Government’s superior interest in this area.

Against this Constitutional backdrop, Congress passed the Immigration Act of 1891. Among other things, it created “the office of superintendent of immigration” inside the Treasury Department, required inspection on arrival, empowered inspection officers to administer oaths and take testimony, built a rudimentary administrative appeal path (to the superintendent, then review by the Secretary of the Treasury), and established early removal/return mechanisms for unlawfully arriving individuals. That model – inspection, administrative decision, limited review – foreshadows the modern U.S. pattern: much of immigration law is executed through administrative processes rather than criminal trials. 

By 1933, the federal government consolidated key functions as related to immigration into an entity called the Immigration and Nationality Service (INS). By 1940, with wartime security concerns, the federal government reorganized immigration-related authority under the Department of Justice (a shift recorded in federal archival histories and reflected in statutory notes concerning executive reorganization). Id.

Finally, the Homeland Security Act of 2002 abolished INS, created the Department of Homeland Security (DHS) ,and transferred a wide range of border and immigration functions into the new department. That statute is the anchor document for the post-9/11 reorganization, including the eventual redistribution of INS functions.  In the first DHS appropriations cycle (FY2004), congressional documents already reflected ICE as a major operational component with multi-billion-dollar funding.

c. Internal Structure Today

ICE’s internal structure is best understood as three core operational “pillars,” supplemented by oversight and support functions. Congress itself describes ICE’s mission this way: ICE enforces federal laws governing “border control, customs, trade, and immigration,” and then differentiates its major subcomponents: HSI (criminal investigation), ERO (civil immigration enforcement), and OPLA (government counsel in removal proceedings and legal advice to ICE personnel). 

• Enforcement and Removal Operations (ERO). ERO is the civil immigration enforcement arm: it identifies and apprehends removable noncitizens, detains when necessary, and carries out removals. The key point is that ERO is not a “border patrol”; it is an interior enforcement agency as well as a detention/removal logistics machine. 

• Homeland Security Investigations (HSI). HSI is described by Congress as conducting criminal investigations into illegal movement of people, goods, money, contraband, weapons, and sensitive technology (domestically and overseas) aiming to disrupt transnational criminal networks. HSI therefore resembles a broad federal investigative service with an international footprint, not just an “immigration” unit. 

• Office of the Principal Legal Advisor (OPLA). OPLA is the government’s legal representative in removal proceedings before DOJ’s immigration court system and provides legal counsel to ICE. In effect, OPLA is the “prosecutor” side of the civil removal system (though removal is civil, not criminal). 

Within DHS, Congress established independent or semi-independent oversight structures that directly affect ICE:

• Civil Rights and Civil Liberties (CRCL). DHS’s civil-rights officer has statutory duties to review and assess civil rights/civil liberties abuses (including profiling), to oversee compliance with constitutional and legal requirements in DHS programs, and to investigate complaints unless the Inspector General takes them. The statute also requires annual reporting to Congress. The Trump Administration attempted to do away with this agency at the beginning of 2025, but reversed such a decision to shutter the office’s doors after a successful lawsuit brought by Robert F. Kennedy Human Rights, Southern Border Communities Coalition, and Urban Justice Center. The CRCL remains operational as a result of this lawsuit, though human rights activists criticize that the agency remains largely understaffed due to layoffs within the Department (a reduction of staff from 150 to 9).

• Immigration Detention Ombudsman (OIDO). OIDO is created by statute as an independent ombuds position reporting directly to the DHS Secretary. Its statutory functions include receiving and investigating complaints, conducting unannounced inspections of immigration detention facilities (including state/local and private facilities holding federal detainees), confidential detainee access, and annual reporting. Similar criticisms have arisen related to the gutting of these offices, with Congress presently debating whether to formalize furloughs via an appropriations bill.

If these bodies are weakened, ICE’s already-insulated environment (detention sites, rapid transfers, limited public access) becomes less visible to Congress, courts, and the public.

d. Thoughts on Naming

Language does not merely describe institutions; it can also create expectations about what institutions are for.

In plain English, “enforcement” is the act of making compliance happen: often by threat or use of coercion. Even without a dictionary, the “force” embedded inside en-force-ment is hard to miss. That matters because the U.S. immigration system is not structured as a single “ministry” with one coherent procedure. It is a patchwork of civil administrative processes enforced by multiple police-like actors, and the label “enforcement” is the conceptual bridge that makes heavy coercion seem normal. 

ICE’s creation also coincided with institutional renaming and reframing: immigration functions were moved into a department whose name foregrounds “homeland security.” The label “security” changes the normative baseline: it invites the public to evaluate migration decisions as “threat-response,” not as ordinary administration of residence, labor, family reunification, and humanitarian protection. 

A vivid example of naming as tone-setting is the 2025 executive action directing a rebrand of the U.S. Department of Defense as the “Department of War.” The executive order explicitly argues that the older label signals strength and willingness to fight. In other words,  it makes an argument about public psychology and institutional posture through the label itself. 

Whether one views that move as symbolism or substance, it illustrates the same analytic point: names can be used to normalize a governing style. ICE’s name performs similar work in the migration context. By foregrounding “enforcement,” and situating immigration within a department defined by “homeland security,” the United States signals that migration governance is to be understood through a security lens rather than as routine civil administration.

For readers in Spain, the contrast is especially clear. Spain’s national immigration authority, the Ministerio de Inclusión, Seguridad Social y Migraciones, embeds migration within a framework of social inclusion, labor policy, and social protection. If that ministry were suddenly rebranded as the Ministerio de Seguridad Nacional, the public meaning of immigration administration would shift immediately. The legal statutes might remain unchanged, but the normative baseline would not. Immigration would be reframed as a security matter first and an administrative or social one second.

In short, naming does not merely describe what an institution does; it helps define what the public believes the institution is for.

II. The Agency’s Powers

8 U.S.C. §1357 authorizes immigration officers (as designated by regulation) to exercise several important powers “without warrant,” including:

• Interrogation power: to interrogate “any alien or person believed to be an alien” regarding their right to be or remain in the United States. 

• Warrantless arrest power: arrest without warrant in specified circumstances (for example, certain entry violations “in his presence or view,” and certain interior arrests based on “reason to believe” plus likelihood of escape before a warrant can be obtained). 

• Border-area boarding/search authority: within a “reasonable distance” (topic of discussion in next section) from an external boundary, officers may board and search conveyances “for aliens,” and within 25 miles they may access “private lands, but not dwellings,” for border-patrol purposes.  Federal regulations define “reasonable distance” for §1357(a)(3) as 100 air miles from an external boundary (land borders and territorial sea), while allowing shorter distances set by relevant officials and even, in “unusual circumstances,” a process to justify more than 100 miles with higher-level approval. The practical effect is that a large percentage of the U.S. population lives within that 100-mile belt, which affects interior enforcement possibilities (especially vehicle and transportation corridors).

• Firearms and process service: officers may carry firearms and execute/serve orders, warrants, subpoenas, summonses, and other process issued under U.S. authority (subject to statutory conditions, including training and use-of-force regulatory requirements for certain arrest authority). 

• 287(g) delegation: the statute authorizes written agreements allowing state or local officers to perform certain immigration officer functions under federal supervision, clarifies training/certification requirements, and addresses liability/immunity mechanics. 

To be clear, this is a police-style statute embedded in a civil administrative system. Many legal consequences occur without a criminal conviction, because removability is a civil status determination, but enforcement tools can look and feel like criminal law enforcement. Let’s take a closer look at this civil agency’s powers that give it a criminal law enforcement agency “feel” in closer detail.

1. The power to detain

ICE’s day-to-day coercive power depends heavily on detention authority, which can be understood in three distinct legal “buckets,” each governed by different statutes and constitutional limits.

• Pre‑removal‑order detention (with availability of bond): Pre-removal detention authority refers to the government’s power to hold someone in immigration custody while their deportation case is still being decided. These powers come mainly from sections 1225 and 1226 of the Immigration and Nationality Act. The Supreme Court addressed these detention statutes in Jennings v. Rodriguez. In that case, the Ninth Circuit Court of Appeals for the United States ruled that people detained under sections 1225(b), 1226(a), and 1226(c) were entitled to regular bond hearings if their detention became prolonged. The Supreme Court disagreed. It held that the statutes themselves do not require automatic bond hearings and rejected the lower court’s attempt to read such a requirement into the law using a doctrine called constitutional avoidance. In practical terms, Jennings means that immigration detention during removal proceedings does not automatically trigger periodic bond hearings unless Congress clearly provides for them in the statute.

• Mandatory detention (without bond): Certain non-citizens, mainly those with specific criminal convictions (e.g., simple possession of cocaine), are subject to what is called “mandatory detention” under section 1226(c) of the Immigration and Nationality Act. This means ICE must detain them during their removal proceedings and they are generally not eligible for bond. The Supreme Court upheld this system in Demore v. Kim. The Court ruled that Congress may require detention without bond for these categories of individuals while their cases are pending. At the same time, the Court made clear that federal courts still retain the power to hear constitutional challenges through habeas corpus, even though section 1226(e) limits review of discretionary custody decisions. In simple terms, Demore confirmed that mandatory detention is lawful in principle, but it did not eliminate the ability to challenge unconstitutional detention in federal court.

• Post‑order detention: Detention after a final order of removal is governed by a different statute, section 1231 of the Immigration and Nationality Act. This provision applies once an immigration judge has issued a final removal order and the government is trying to carry out the deportation. In Zadvydas v. Davis, the Supreme Court addressed how long someone can be detained under this post-order authority. The Court held that the statute does not allow indefinite detention. Using a method of interpretation known as constitutional avoidance, the Court read section 1231 as containing an implicit time limit. It established a presumptive six-month period: after six months of post-order detention, if there is no significant likelihood that removal will occur in the reasonably foreseeable future, continued detention becomes legally problematic. In practical terms, Zadvydas means that once a person has a final removal order, ICE cannot simply detain them forever if deportation is not realistically going to happen.

These cases matter because they determine how long ICE can keep someone detained. The longer detention lasts, the more it can function as a form of pressure. Even if deportation is legally uncertain or practically unlikely, prolonged detention can push individuals to give up claims, accept removal, or abandon legal defenses simply to regain their freedom.

b. The power to arrest

Regulations in 8 C.F.R. Part 287 define who qualifies as an “immigration officer” and delineate the scope of their authority, including arrest powers exercised under 8 U.S.C. § 1357 and related detention statutes.

In practice, ICE, particularly Enforcement and Removal Operations (ERO), initiates civil immigration arrests and detention decisions under those statutory authorities. However, the actual selection of targets has historically been influenced by executive-branch enforcement priorities. At times, those priorities have been formalized in written memoranda. The 2021 DHS enforcement priorities memorandum, for example, explicitly framed immigration enforcement as an exercise of prosecutorial discretion, emphasized that DHS lacks the resources to remove all removable individuals, and announced priority categories such as national security threats, public safety risks, and recent border entrants.

At present, however, the landscape has shifted. Formal nationwide priority frameworks have been withdrawn, narrowed, or deemphasized depending on administration policy changes and litigation outcomes. In the absence of clearly articulated limiting priorities, enforcement discretion broadens. Field offices may operate with fewer categorical constraints, and arrest decisions can become more dependent on operational directives, resource surges, and institutional momentum rather than explicit national-level prioritization criteria.

At the same time, enforcement intensity can expand rapidly through operational campaigns, staffing surges, and detention expansion. These initiatives can produce what communities experience as “sweeps,” often accompanied by rapid inter-facility transfers. A recent federal court  order responding to “Operation Metro Surge” found that ICE practices during that surge effectively blocked detainee access to attorneys through rapid transfers and communication barriers, and ordered immediate corrective measures including confidential communication safeguards and limitations on disruptive transfers.

In short, while statutory authority provides the legal baseline for arrest, the real-world scope and texture of enforcement depend heavily on whether executive leadership constrains that authority through defined priorities or allows it to operate at full discretionary capacity.

c. Present budget

ICE’s budget is now at or near the highest level in its history. That fact alone is significant. When an enforcement agency reaches record funding levels, it signals that the federal government is not retreating from that mission, but rather, reinforcing it.

Since ICE was created in 2003, its annual funding has generally trended upward, with fluctuations depending on administration priorities and congressional negotiations. But in recent years, total funding has reached unprecedented levels, presently at about $10 billion per year. Even without listing every line item, the bottom line is clear: ICE today operates with more financial resources than at any previous point since its creation.

Why does that matter in practical terms?

A larger budget translates into:

• More personnel, including enforcement officers and investigative agents
• Greater detention capacity through contracts with private and local facilities
• Expanded transportation and logistics for removals
• Broader investigative operations
• More sophisticated technology and data systems

In other words, budget size directly determines operational reach. Record-level funding means record-level potential enforcement capacity. Whatever political debates surround immigration policy in the United States, the financial commitment to immigration enforcement remains strong and historically high. The budget level reflects not temporary rhetoric, but institutional investment.

III. Present Controversies

The most significant debates surrounding ICE today do not center on whether the agency has statutory authority. That authority is more or less well established in the Immigration and Nationality Act. The controversies instead concern how that authority is exercised, how visible it is to the public, and how effectively it is constrained. What follows examines some of the fault lines.

a. Weakened Oversight

A major area of controversy involves oversight institutions themselves. ICE operates within a web of executive, legislative, and judicial oversight structures. The present debate concerns whether those structures are functioning as intended or are being narrowed.

i. Executive oversight

As alluded to previously, Congress has created internal watchdog offices within DHS. The Office for Civil Rights and Civil Liberties is tasked with investigating allegations of profiling and abuse and producing annual reports. The Office of the Immigration Detention Ombudsman has statutory authority to inspect facilities, receive complaints, and access detention centers. Recent reporting in 2025 described efforts within DHS to reduce or dismantle some of these oversight functions. Litigation followed, with arguments that offices created by statute cannot be eliminated without congressional action.

Whatever the outcome of those legal disputes, the controversy reveals a structural vulnerability. Oversight offices, even when created by law, can be weakened through staffing reductions, budget constraints, or administrative restructuring. Critics argue that this creates an asymmetry in which enforcement capacity expands while oversight capacity contracts.

ii. Legislative oversight 

Congress retains authority through appropriations. Funding bills can include reporting requirements, contract disclosure mandates, and restrictions tied to programs such as 287(g) local partnerships or detention contracting performance. However, legislative oversight depends heavily on political alignment and committee priorities. It is episodic rather than continuous. In periods of partisan polarization (such having been the case in the U.S. for almost two decades), oversight hearings may become symbolic rather than corrective. As a result, the controversy is not about whether Congress has authority, but whether it is using it robustly.

iii. Judicial oversight

Courts intervene episodically in immigration enforcement, usually through habeas petitions, class actions, and constitutional claims. Supreme Court decisions new and hold, however, have generally narrowed the scope of judicial intrusion into immigration and border enforcement. Key pressure points include:

• Racial Profiling and Equal Protection Claims: In Noem v. Vasquez Perdomo (2025), the Supreme Court temporarily blocked a lower federal court order that had limited how ICE agents could conduct stops and arrests in the Los Angeles area. The district court had prohibited agents from relying primarily on factors such as race, ethnicity, language, or occupation when forming reasonable suspicion for immigration stops, finding that such practices likely violated the Fourth Amendment. By granting the government’s emergency request for a stay, the Supreme Court allowed ICE enforcement operations to continue without those restrictions while the case proceeds on appeal. The Court did not issue a full opinion on the merits, but the practical effect is significant: ICE agents may continue conducting stops under their existing practices unless and until a final ruling says otherwise. In practical terms, the decision gives immigration officers broader operational discretion in the field and makes it more difficult, at least for now, for lower courts to impose systemic limits on enforcement tactics tied to demographic indicators.

• Excessive Force and Damages Remedies: In Egbert v. Boule, the Supreme Court ruled that people generally cannot sue federal immigration or border officers for money damages under the implied “Bivens” cause of action when those officers are alleged to have used excessive force or violated constitutional rights during immigration enforcement. Petitioner Boule argued that a Border Patrol agent used unauthorized force and retaliated against him in violation of the Fourth and First Amendments. The Court declined to extend Bivens to this context, emphasizing that national security and border enforcement involve sensitive policy judgments best left to Congress. Practically, the decision means that individuals who believe immigration agents have violated their constitutional rights now face a much higher hurdle to obtain monetary compensation from those officers. Unless Congress has expressly authorized a damages remedy, courts will not imply one. As a result, accountability through personal liability suits against federal immigration agents is significantly limited, reducing a key form of judicial check on enforcement conduct.

• Fourth Amendment and the Border Zone: In United States v. Martinez-Fuerte, the Supreme Court upheld the constitutionality of fixed immigration checkpoints set up by the U.S. Border Patrol on highways well inland from the border. Agents stopped vehicles without individualized reasonable suspicion at permanent or temporary checkpoints to verify passengers’ immigration status. The Court ruled that these checkpoint stops were reasonable under the Fourth Amendment because the intrusion on motorists was limited and the government’s interest in controlling illegal immigration at or near the border was significant. The decision distinguished these stops from roving, suspicionless searches, finding that interior checkpoints serve a similar purpose to border searches and involve less intrusion given the structured and publicly known nature of the stops. Martinez-Fuerte establishes that, in certain contexts tied to border enforcement, officers may stop vehicles at designated checkpoints without individualized suspicion, so long as the intrusion is minimal and regulated.

• Access to Counsel and Procedural Fairness: In INS v. Lopez-Mendoza, 468 U.S. 1032 (1984), the Supreme Court held that removal proceedings are civil, not criminal, and therefore do not carry all the constitutional protections that apply in criminal trials. Most notably, the Court ruled that the Fourth Amendment exclusionary rule, which suppresses unlawfully obtained evidence in criminal cases, generally does not apply in deportation hearings. The Court reasoned that the costs of excluding evidence in civil immigration proceedings outweigh the deterrent benefits. The decision reinforces the principle that removal is an administrative process, limiting the availability of certain constitutional remedies in immigration court.

• Federalism and Masking — Supremacy Clause Litigation (California 2026): In early February 2026, a federal district court in Los Angeles struck down a California state law that would have banned federal officers, including ICE agents, from wearing masks while on duty. The judge found that the mask prohibition, as written, violated the U.S. Constitution’s Supremacy Clause because it singled out federal officers while exempting state law enforcement, treating the federal government differently from the state. The court granted a preliminary injunction blocking enforcement of the mask ban, meaning it cannot be applied while the case continues. At the same time, the judge upheld a separate California law requiring federal officers to visibly display identification such as agency and badge numbers, which is set to take effect later. The ruling reflects the continuing tension between state efforts to increase accountability and federal authority over immigration enforcement.

b. Training

A final present controversy involves staffing expansion and internal culture.

As ICE’s budget has increased, hiring efforts have expanded. Recruitment bonuses, accelerated onboarding, and efforts to fill operational gaps have raised questions about vetting standards and training depth. Critics argue that rapid expansion risks weakening institutional safeguards. Supporters argue that increased staffing is necessary to meet statutory mandates and operational demands.

In enforcement agencies, training does more than teach procedure. It shapes constitutional compliance, discretionary decision making, and engagement with vulnerable populations. The controversy, therefore, is not simply about numbers. It is about institutional culture and the long-term character of immigration enforcement.

IV. Conclusion

ICE is not simply an agency. It is an institutional expression of how the United States has chosen to structure immigration governance in the twenty-first century. It reflects a system in which migration control is embedded within a security framework, administered through civil proceedings, and enforced with police-style tools. Arrest, detention, and removal occur within an administrative process, yet the experience of that process can resemble criminal law enforcement in both form and consequence.

The agency’s authority is not accidental. It rests on statutes enacted by Congress, judicial decisions that define the outer constitutional boundaries of detention and enforcement, and appropriations that continue to fund ICE at historically high levels.  At the same time, ICE’s modern footprint is shaped as much by structure and oversight as by statute. Transparency in detention conditions, the vitality of internal watchdog offices, the scope of executive enforcement priorities, the availability of judicial remedies, and the training and culture of personnel all influence how authority is exercised on the ground. When oversight mechanisms weaken or data become difficult to interpret, the formal boundaries of law may remain intact while practical accountability erodes.

For readers outside the United States, the central insight is this: American immigration enforcement is not merely a bureaucratic function of residence administration. It is a security-oriented, federally centralized enforcement regime operating inside a civil legal framework. ICE occupies the enforcement pole of a fragmented immigration system, and its evolution reflects broader debates about federal power, constitutional limits, and the meaning of how migrants are treated: are they matters of homeland security or, as Spain has classified, a group of people to be “included” into society?

Whether one views ICE as necessary infrastructure, excessive coercion, or something in between, it cannot be understood in isolation. It must be understood as part of a larger architecture of law, politics, and institutional design. That architecture continues to evolve. The questions that remain are not only about what ICE is authorized to do, but about how visible, how restrained, and how accountable that authority will be in practice.

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Disclaimer:

This article is provided for informational purposes only. It does not constitute legal advice and does not create an attorney-client relationship. Each case depends on its specific facts and circumstances. Individuals should seek individualized advice from a licensed U.S. immigration attorney before making travel or immigration-related decisions. All rights reserved. While every effort has been made to ensure accuracy, any errors or omissions are the author’s own. Readers are welcome to contact the author with corrections or feedback.