Anti-Terrorism Laws: Federal Crimes, Statutes, and Agencies

Federal anti-terrorism laws in the United States are not a single statute but a layered system: definitions in 18 U.S.C. § 2331 that classify conduct as domestic or international terrorism, criminal statutes that punish the underlying acts (most often material support under 18 U.S.C. §§ 2339A and 2339B), post-9/11 legislation that expanded investigative tools, financial rules that cut off terrorist funding, and a group of agencies — chiefly the FBI, DHS, Treasury, and the State Department — that share enforcement. Most federal terrorism prosecutions run through the material support statutes, which carry up to 20 years in prison and life if a death results.

How Federal Law Defines Terrorism

Under 18 U.S.C. § 2331, the line between international and domestic terrorism is drawn mainly by geography. International terrorism covers violent acts that violate criminal law and occur primarily outside U.S. borders or cross national boundaries. Domestic terrorism covers the same kinds of conduct when it occurs primarily inside the United States.¹

Both categories share the same elements. The acts must be dangerous to human life and violate federal or state criminal law, and they must appear intended to intimidate or coerce civilians, pressure the government through intimidation, or influence government conduct through mass destruction, assassination, or kidnapping.¹

These definitions do not create standalone crimes. Nobody is charged with “domestic terrorism” as a single offense. The definitions instead trigger enhanced sentencing, investigative authorities, and national-security treatment. Prosecutors build actual charges around specific conduct statutes.

The Core Federal Terrorism Crimes

Material support charges do most of the work in federal terrorism prosecutions, and two statutes cover the ground.

18 U.S.C. § 2339A applies to anyone who provides support knowing it will be used to carry out specific violent crimes, including bombings, hostage-taking, and attacks on infrastructure. Material support is defined broadly to include money, lodging, training, weapons, false identification, communications equipment, transportation, and personnel. Medicine and religious materials are the only carve-outs. The maximum sentence is 15 years, or life if someone dies.²

18 U.S.C. § 2339B goes further. It criminalizes knowingly providing material support to any group the government has designated as a foreign terrorist organization, whether or not the support was meant for violent purposes. Money earmarked for a designated group’s charitable programs can still trigger prosecution. The maximum is 20 years, and life if a death results.³

To convict under § 2339B, the government must prove the defendant knew the recipient was a designated terrorist organization or engaged in terrorism. People who act entirely on their own to advance a group’s goals, without working under its direction, are not treated as having provided “personnel.” The Secretary of State, with the Attorney General’s concurrence, may grant exceptions for training or expert advice.³

Separately, 18 U.S.C. § 2332a covers using or threatening to use weapons of mass destruction. Punishment runs up to life imprisonment, and the death penalty is available if anyone dies.⁴

Major Anti-Terrorism Statutes

Antiterrorism and Effective Death Penalty Act of 1996

The AEDPA laid much of the groundwork for modern federal terrorism law. It restricted inmates’ ability to file repeat challenges to their convictions in federal court, which accelerated capital appeals. It also expanded federal jurisdiction over crimes involving biological, chemical, and nuclear weapons, with penalties reaching life imprisonment or death.⁵

The USA PATRIOT Act

Enacted after September 11, 2001, the PATRIOT Act significantly expanded investigative authority. It authorized roving wiretaps, letting federal agents follow a surveillance target across multiple phones and devices under a single court order rather than obtaining a new warrant for each device. It also permitted delayed-notice search warrants, in which agents execute a court-approved search and notify the subject afterward to avoid tipping off accomplices.⁶

The act tore down the legal wall between criminal investigations and foreign intelligence gathering, allowing agencies to share grand jury information and wiretap data. It raised criminal penalties for providing material support to foreign organizations that engage in violence. Section 215, one of the more controversial provisions, authorized the government to compel businesses to produce records deemed relevant to national security investigations.

Several key provisions, including roving wiretaps and the Section 215 business records authority, were subject to sunset clauses. They expired on March 15, 2020, and Congress has not reauthorized them. A grandfather clause keeps them in effect for investigations already underway before that date, but the government cannot initiate new actions under these authorities.⁷

USA FREEDOM Act

Before those provisions lapsed, the USA FREEDOM Act of 2015 had already reined in one of the most controversial PATRIOT Act programs. It ended the government’s bulk collection of phone call metadata, which had allowed the NSA to sweep up records on millions of Americans’ calls. Under the revised framework, telecommunications companies retained the data, and the government needed a specific court order to query it.⁸

Surveillance Authority Under FISA

The Foreign Intelligence Surveillance Act provides the legal framework for electronic surveillance of agents of foreign powers inside the United States. Before wiretapping a suspected spy or international terrorist on U.S. soil, the government must obtain an order from the Foreign Intelligence Surveillance Court, a specialized body of 11 federal district court judges designated by the Chief Justice.⁹ The court reviews applications in classified proceedings.¹⁰

How long surveillance can last depends on the target. Orders against a foreign power itself can run up to one year, as can orders against non-U.S. persons who are agents of a foreign power. For U.S. persons, the maximum is 90 days. The government must apply for an extension before authorization expires to keep collecting.¹¹

Section 702 works differently. It allows targeting of non-U.S. persons reasonably believed to be outside the country without individual court orders for each target. The court approves annual certifications and reviews the procedures the government uses to ensure it targets foreigners abroad and minimizes any U.S. person information it incidentally collects.¹⁰ Section 702 was reauthorized in April 2024 under the Reforming Intelligence and Securing America Act for a two-year period, with expiration approaching in 2026.¹²

Counter-Terrorism Financing Rules

Cutting off money is a central strategy, and financial compliance failures carry weight. The Bank Secrecy Act requires financial institutions to maintain detailed records and file a Currency Transaction Report for any cash transaction over $10,000.¹³ Banks must also verify who holds each account through customer identification programs, and they must file Suspicious Activity Reports for transactions that appear to lack a legitimate business purpose or involve potential criminal conduct. SARs must reach the Financial Crimes Enforcement Network within 30 days of initial detection; if no suspect has been identified, the institution gets an additional 30 days.¹⁴

The Treasury Department’s Office of Foreign Assets Control maintains the Specially Designated Nationals and Blocked Persons list, which identifies individuals and entities connected to terrorism, narcotics trafficking, and other sanctioned activities.¹⁵ Any assets belonging to someone on the list that touch the U.S. financial system must be frozen immediately, and doing business with a listed person or entity is broadly prohibited.

Criminal penalties for willful BSA violations reach up to five years in prison and a $250,000 fine. If the violation is part of a pattern of illegal activity involving more than $100,000 over 12 months, the maximum jumps to 10 years and a $500,000 fine.¹⁶ Knowingly providing funds or financial services to a designated foreign terrorist organization falls under the material support statutes, with penalties up to 20 years.³ Financial institutions that knowingly fail to freeze assets when required face civil penalties of at least $50,000 per violation.

Which Agencies Enforce Anti-Terrorism Laws

No single agency runs the counter-terrorism apparatus. Work is divided among departments with overlapping missions.

The FBI has primary responsibility for domestic terrorism investigations under 28 C.F.R. § 0.85, which assigns it broad authority to investigate federal offenses and gather evidence for the government.¹⁷ The bureau operates Joint Terrorism Task Forces that combine federal, state, and local officers into unified teams.

The Department of Homeland Security handles border security, airport passenger screening, and emergency response coordination. Through the Cybersecurity and Infrastructure Security Agency, DHS oversees protection of 16 critical infrastructure sectors whose disruption could carry serious national security and public health consequences.¹⁸

The State Department holds the authority to designate groups as Foreign Terrorist Organizations under Section 219 of the Immigration and Nationality Act. A group qualifies if it is foreign, engages in terrorism or retains the intent and capability to do so, and its activity threatens U.S. nationals or national security.¹⁹ Once designated, it becomes illegal for anyone in the United States to provide support to the group, and its members can be denied visas.²⁰

The National Counterterrorism Center serves as the central hub for threat analysis, pulling together intelligence from across every branch of government so that information reaches the right people quickly.

If You’ve Been Wrongly Affected

Anti-terrorism measures sometimes sweep in the wrong people. Watch list misidentifications, asset freezes based on mistaken identity, and travel disruptions all happen, and the law provides ways to push back.

Anyone repeatedly pulled aside for additional screening, denied boarding, or delayed at a border crossing can file an inquiry through the DHS Traveler Redress Inquiry Program. The process runs through an online portal at DHS.gov, and applicants receive a seven-digit Redress Control Number to use when booking future travel once the inquiry is resolved.²¹

If your assets are frozen because you appear on the SDN list, you can petition OFAC in writing for removal. The petition must include proof of identity, a description of the listing you are challenging, and a detailed explanation of why delisting is appropriate. OFAC generally acknowledges receipt within seven business days and aims to send its first follow-up questionnaire within 90 days. Grounds for removal include mistaken identity, changed circumstances, or evidence that the original basis for the listing no longer applies. An attorney is not required, but submitting false information can trigger enforcement action.²²

Broader oversight of executive branch anti-terrorism programs falls to the Privacy and Civil Liberties Oversight Board, an independent federal body that reviews whether security measures appropriately balance national defense with constitutional rights. The board has conducted reviews of FISA Section 702, TSA facial recognition technology, the terrorist watchlist, and FBI collection of publicly available data.²³

1
Office of the Law Revision Counsel. 18 USC 2331 – Definitions
2
Office of the Law Revision Counsel. 18 USC 2339A – Providing Material Support to Terrorists
3
Office of the Law Revision Counsel. 18 USC 2339B – Providing Material Support or Resources to Designated Foreign Terrorist Organizations
4
Office of the Law Revision Counsel. 18 USC 2332a – Use of Weapons of Mass Destruction
5
Congress.gov. Antiterrorism and Effective Death Penalty Act of 1996
6
Department of Justice. The USA PATRIOT Act: Preserving Life and Liberty
7
Congress.gov. Origins and Impact of the Foreign Intelligence Surveillance Act (FISA)
8
Intelligence.gov. Fact Sheet: Implementation of the USA FREEDOM Act of 2015
9
Office of the Law Revision Counsel. 50 USC 1803 – Designation of Judges
10
Office of the Director of National Intelligence. Categories of FISA
11
Office of the Law Revision Counsel. 50 USC 1805 – Issuance of Order
12
Congress.gov. H.R.7888 – Reforming Intelligence and Securing America Act
13
Federal Deposit Insurance Corporation. Bank Secrecy Act, Anti-Money Laundering, and Office of Foreign Assets Control
14
Financial Crimes Enforcement Network. FinCEN Suspicious Activity Report Electronic Filing Instructions
15
U.S. Department of the Treasury. Specially Designated Nationals (SDNs) and the SDN List
16
Office of the Law Revision Counsel. 31 USC 5322 – Criminal Penalties
17
eCFR. 28 CFR 0.85 – General Functions
18
Cybersecurity and Infrastructure Security Agency. Critical Infrastructure Security and Resilience
19
Office of the Law Revision Counsel. 8 USC 1189 – Designation of Foreign Terrorist Organizations
20
United States Department of State. Foreign Terrorist Organizations
21
Homeland Security. Traveler Redress Inquiry Program (DHS TRIP)
22
U.S. Department of the Treasury. Filing a Petition for Removal from an OFAC List
23
Privacy and Civil Liberties Oversight Board. Home