In recent months, the U.S. Immigration and Customs Enforcement (ICE) agency has been the subject of significant public attention and litigation, raising questions about immigration policy, constitutional rights, and public safety law.

Public debate often focuses on individual enforcement actions. But understanding today’s immigration landscape requires deeper context, including the statutory framework that created ICE, the laws that define its authority, and the constitutional protections that apply to all persons within the United States.

This post provides an overview of:

• How the Department of Homeland Security (DHS) was created
• The statutory authority governing ICE
• The constitutional protections that apply to noncitizens and U.S. citizens
• How researchers can explore these issues using HeinOnline’s specialized immigration database

The Creation of the Department of Homeland Security

The modern structure of federal immigration enforcement emerged in the aftermath of the September 11, 2001 terrorist attacks. In response, Congress enacted the Homeland Security Act of 2002,^[1]Homeland Security Act of 2002., Public Law 107-296, 107 Congress. 116 Stat. 2135 (2002). This document can be found in HeinOnline’s U.S. Statutes at Large database. which reorganized federal agencies and created the Department of Homeland Security. The Act transferred immigration enforcement responsibilities from the former Immigration and Naturalization Service (INS), which had been housed within the Department of Justice, into the new department.

Under the Act:

• ICE was created to handle interior enforcement removal operations
• U.S. Customs and Border Protection (CBP) became responsible for border enforcement
• U.S. Citizenship and Immigration Services (USCIS) took over immigration benefits processing

ICE was not created as a stand-alone agency; it was established by Congress as a component of the Department of Homeland Security.

ICE’s Statutory Authority

ICE primarily enforces provisions of the Immigration and Nationality Act (INA), originally enacted in 1952 and amended numerous times since. Several key sections define the scope and limits of ICE’s enforcement authority and are frequently interpreted by federal courts.

• 8 U.S.C. § 1226
  This section governs the apprehension, arrest, detention, and release of noncitizens^[2]2018 Edition v. 4 Titles (7-10) 850 (2018) Sections 1226 – 1227. This document can be found in HeinOnline’s U.S. Code database. who are in removal proceedings.
• 8 U.S.C. § 1231
  This section governs detention and removal after a final order of removal has been issued.^[3]2018 Edition v. 4 Titles (7-10) 878 (2018) Sections 1230 – 1232. This document can be found in HeinOnline’s U.S. Code database. It establishes a 90-day “removal period,” during which the government must attempt to effectuate removal, and authorizes continued detention in certain circumstances beyond that period. Federal courts have interpreted this provision in cases addressing prolonged detention.
• 8 U.S.C. § 1357
  This section outlines the powers of immigration officers, including the authority to interrogate, arrest, detain, and search individuals suspected of immigration violations,^[4]2018 Edition v. 4 Titles (7-10) 990 (2018) Sections 1357 – 1358. This document can be found in HeinOnline’s U.S. Code database. including making warrantless arrests in certain circumstances and exercising limited enforcement powers near U.S. borders.
• 8 U.S.C. §§ 1325–1326
  These sections criminalize unlawful entry into the United States and unlawful reentry after removal, establishing penalties for individuals who enter without inspection or return after being deported or denied admission.^[5]2018 Edition v. 4 Titles (7-10) 971 (2018) Sections 1324 – 1326. This document can be found in HeinOnline’s U.S. Code database.

Constitutional Protections and Legal Limits

ICE’s authority is grounded in federal statutes, and that authority operates within constitutional boundaries. Immigration enforcement actions are constrained by the U.S. Constitution, and these constitutional protections apply to all persons within the United States.

Fourth Amendment

The Fourth Amendment^[6]2022 Edition Annotating Interpretations to Various Articles of the Constitution 1609 (2023) Fourth Amendment: Searches and Seizures. This document can be found in HeinOnline’s World Constitutions Illustrated database. protects individuals against unreasonable searches and seizures. These protections apply to immigration enforcement actions conducted within the United States, including arrests and detentions carried out by ICE officers.

Under 8 U.S.C. § 1357, immigration officers are authorized to make certain warrantless arrests and conduct limited enforcement activities, subject to constitutional constraints. Courts evaluate compliance with the Fourth Amendment by looking at all the circumstances.

Although the Supreme Court has not issued many recent immigration-specific Fourth Amendment decisions, general Fourth Amendment principles governing stops and seizures continue to apply in immigration enforcement contexts.

Fifth Amendment

The Fifth Amendment^[7]2022 Edition Annotating Interpretations to Various Articles of the Constitution 1693 (2023) Fifth Amendment: Rights of Persons. This document can be found in HeinOnline’s World Constitutions Illustrated database. guarantees that no person shall be deprived of life, liberty, or property without due process of law. The Supreme Court has recognized that these protections apply to noncitizens who are physically present in the United States, including those in removal proceedings.

In the immigration context, due process generally includes notice of the charges, an opportunity to be heard, and the ability to present evidence before an immigration judge. Although immigration law is considered a civil system, removal proceedings must still comply with constitutional requirements.

Equal Protection Principles

Although the Equal Protection Clause^[8]2022 Edition Annotating Interpretations to Various Articles of the Constitution 2065 (2023) Section 1: Rights. This document can be found in HeinOnline’s World Constitutions Illustrated database. appears in the Fourteenth Amendment, which applies directly to the states, the Supreme Court has interpreted the Fifth Amendment’s Due Process Clause to incorporate equal protection principles at the federal level. As a result, federal immigration policies and enforcement practices are subject to constitutional review under equal protection standards.

Challenges to immigration laws and enforcement actions sometimes allege discrimination based on race, nationality, or other protected characteristics. Congress’s authority over immigration is subject to constitutional review.

Researching This Topic in HeinOnline

With so many legal interpretations, court decisions, legislative histories, and regulatory changes shaping immigration law, researchers often need access to authoritative primary sources and historical context.

Immigration law is particularly complex because it draws from constitutional law, federal statutes, administrative regulations, and decades of judicial interpretation.

That’s where HeinOnline’s Immigration Law & Policy in the U.S. database becomes especially valuable.

About Immigration Law & Policy in the U.S.

HeinOnline’s Immigration Law & Policy in the U.S. provides comprehensive coverage of the legal framework shaping immigration enforcement and policy, bringing together statutory text, legislative materials, administrative decisions, and historical analysis in a single searchable platform.

The database provides access to:

Acts and Legislative Histories

Discover all compiled legislative histories on immigration law. Easily browse acts and their legislative histories by title, public law number, or popular name.

Law and Policy Titles

Access works spanning more than 200 years of law and policy, providing in-depth analyses and discussions that contextualize the evolution of immigration practice.

Government Reports

Find reports on immigration-related federal programs from the Government Accountability Office (GAO) and Congressional Research Service (CRS) reports.

The CFR and U.S. Code

Utilize HeinOnline’s comprehensive digital coverage of Title 8 (Aliens and Nationality) of both the Code of Federal Regulations (CFR) and U.S. Code.

Congressional Hearings

Discover more than 1,000 Congressional hearings and debates on immigration issues, including employment, criminal justice, refugee status, and more.

Extradition Titles

Peruse more than 100 titles on extradition (the act of handing over an accused criminal to another country’s jurisdiction), searchable for the first time.

Users can also locate the most up-to-date opinions and decisions of the U.S. Department of Justice concerning U.S. immigration policy and practice.  BIA Precedent Decisions is a working index to the Administrative Decisions under Immigration and Nationality Laws, containing decisions which have been selected and designated as precedents in accordance with Title 8, Code of Federal Regulations section 3.1(g) and 103.3(c). It includes all opinions and orders of the Attorney General, Board of Immigration Appeals, and the Commissioner of Immigration and Naturalization Service. 

So what exactly can you do with this database?

Researchers can work directly with the primary sources that shape immigration enforcement. With access to statutes, legislative history, and administrative decisions, users can:

• Trace how statutory definitions central to current debates, such as removal authority or asylum standards, have evolved over time
• Review BIA precedent decisions to understand how immigration judges interpret specific provisions in practice
• Examine congressional materials to better understand the legislative intent behind enforcement changes
• Compare historical immigration acts with modern regulations to understand how current policies developed

Together, these resources provide comprehensive support for immigration law research.

For libraries and institutions seeking to support deeper research into immigration law, Immigration Law & Policy in the U.S. is available for trial. Request a trial or a price quote to learn more.

Readers of this blog who request a quote will receive 25% off a new subscription.
Offer valid through May 29, 2026.