The federal Anti-Terrorism Act and the statutes built around it, chiefly the Antiterrorism and Effective Death Penalty Act of 1996 and the USA PATRIOT Act of 2001, criminalize providing material support to terrorists or designated foreign terrorist organizations, punish those crimes with up to 20 years in prison (life if anyone dies), expand federal surveillance and asset-freezing powers, and let U.S. victims of international terrorism sue for triple their actual damages. The framework is broad on purpose. It lets prosecutors act well before an attack and gives the government tools that reach money, communications, and foreign governments.
How Federal Law Defines Terrorism
Both international and domestic terrorism share a core definition under 18 U.S.C. § 2331: acts dangerous to human life that violate federal or state criminal law and appear intended to intimidate civilians, coerce government policy, or affect government conduct through mass destruction, assassination, or kidnapping.1Office of the Law Revision Counsel. 18 U.S. Code 2331 – Definitions The line between the two turns on geography. International terrorism occurs primarily outside the United States or crosses national borders. Domestic terrorism occurs primarily within U.S. borders.
That distinction matters because it controls which tools the government can use. Foreign intelligence surveillance authorities, Foreign Terrorist Organization designations, and certain financial sanctions apply only on the international side. Domestic terrorism investigations generally proceed under standard federal criminal statutes, which is why there are recurring calls for a dedicated domestic terrorism charging statute.
Foreign Terrorist Organization Designations
The Secretary of State can designate a group as a Foreign Terrorist Organization under 8 U.S.C. § 1189 if the organization is foreign, engages in or retains the capability and intent to engage in terrorist activity, and threatens U.S. national security or U.S. nationals.2Office of the Law Revision Counsel. 8 USC 1189 – Designation of Foreign Terrorist Organizations The State Department publishes the list.3United States Department of State. Foreign Terrorist Organizations Once a group is designated, providing it with material support becomes a federal crime, its U.S. assets can be frozen, and foreign nationals tied to it become inadmissible.
The Core Crimes and Their Penalties
The material support statutes are the government’s workhorse terrorism charges. They let prosecutors reach the people and resources behind an attack rather than waiting for the attack itself.
Material Support to a Designated FTO
Under 18 U.S.C. § 2339B, providing material support or resources to a designated FTO is punishable by up to 20 years in federal prison, and by life if anyone dies as a result.4Office of the Law Revision Counsel. 18 USC 2339B – Providing Material Support or Resources to Foreign Terrorist Organizations “Material support” is written broadly: money, training, personnel, expert advice, communications equipment, lodging, transportation, and other services of value. The government does not have to prove you intended to further the group’s violence. It only has to prove you knew the organization was a designated FTO, had engaged in terrorism, or was engaged in terrorist activity.
The Supreme Court upheld that framework in Holder v. Humanitarian Law Project, holding that Congress could constitutionally reach support directed even at a group’s nonviolent activities because designated foreign terrorist organizations are so entangled with criminal conduct that any support facilitates it.5Justia. Holder v. Humanitarian Law Project
Material Support for Specific Terrorist Crimes
A separate statute, 18 U.S.C. § 2339A, criminalizes providing material support when you know or intend it will be used to carry out listed federal offenses such as bombings, hijackings, assassinations, and attacks using weapons of mass destruction. No FTO connection is required. The maximum is 15 years, or life if a death results.6Office of the Law Revision Counsel. 18 U.S. Code 2339A – Providing Material Support to Terrorists
Receiving Military-Type Training
Knowingly receiving military-type training from or on behalf of a designated FTO is its own federal crime under 18 U.S.C. § 2339D, punishable by up to 10 years. The definition covers instruction in methods capable of causing death, serious injury, or property destruction, and training in explosives, firearms, or weapons of mass destruction. Again, the government must prove you knew the group’s terrorist status, not that you intended to carry out an attack.7Office of the Law Revision Counsel. 18 U.S. Code 2339D – Receiving Military-Type Training From a Foreign Terrorist Organization
Weapons of Mass Destruction
Using, threatening to use, or attempting to use a weapon of mass destruction against a U.S. national or within the United States carries any term of years up to life. If anyone dies, the death penalty is available.8Office of the Law Revision Counsel. 18 USC 2332a – Use of Weapons of Mass Destruction
The Sentencing Enhancement That Changes the Math
The statutory maximums tell only part of the story. Federal Sentencing Guideline § 3A1.4 applies when the offense involved or was intended to promote a federal crime of terrorism. It increases the offense level by 12 (with a floor of level 32) and places the defendant in Criminal History Category VI, the most severe category, regardless of any prior record.9United States Sentencing Commission. USSG 3A1.4 – Terrorism In practice this pushes sentences toward the statutory maximum even for first offenders. It’s one of the most aggressive sentencing provisions anywhere in federal law.
Surveillance Powers in Terrorism Investigations
Anti-terrorism legislation reshaped how the government gathers intelligence. It lowered the walls between foreign intelligence and criminal investigation and expanded several specific tools.
Roving Wiretaps
A standard wiretap order is tied to a specific device. A roving order under FISA follows the target instead. When the government shows the target may use or switch devices to defeat surveillance, the court can authorize surveillance that moves with the person. After directing surveillance at a new device, agents must notify the court within 10 days with the details and justification.10Office of the Law Revision Counsel. 50 U.S. Code 1805 – Issuance of Order
Delayed-Notice (“Sneak and Peek”) Warrants
Under 18 U.S.C. § 3103a, agents can enter and search a property without immediately notifying the owner if the court finds reasonable cause that immediate notice would produce an adverse result, such as destruction of evidence, flight, or witness intimidation. The warrant generally bars seizing tangible property unless the court finds a reasonable necessity. Initial delay caps at 30 days, with extensions of up to 90 days at a time when the government shows continued need.11Office of the Law Revision Counsel. 18 USC 3103a – Additional Grounds for Issuing Warrant
The “Significant Purpose” Standard
Before the PATRIOT Act, FISA surveillance required that gathering foreign intelligence be “the purpose” of the investigation, which courts read as the primary purpose. The PATRIOT Act changed that to “a significant purpose.”12Office of the Law Revision Counsel. 50 U.S. Code 1804 – Applications for Court Orders FISA-authorized surveillance can now go forward even when a criminal investigation is the main objective, as long as foreign intelligence gathering remains a significant one.
Section 702 Foreign Surveillance
Section 702 of FISA, enacted in 2008, authorizes the NSA to collect the communications of non-U.S. persons located abroad without individual court orders, provided the targets are foreigners and a significant purpose is foreign intelligence. Because those collections inevitably pick up communications with Americans, Section 702 has drawn sustained debate. Congress reauthorized it in April 2024 through the Reforming Intelligence and Securing America Act (RISAA), a two-year extension that sets a sunset of April 19, 2026. The 2024 law added stricter requirements for FBI queries of the collected data, mandatory court-appointed advocates during certain FISA Court certification reviews, new discipline for noncompliance, and a broader definition of “electronic communications service provider.”13Privacy and Civil Liberties Oversight Board. FISA Section 702 – Oversight Projects
Challenging FISA-Derived Evidence
If your case involves evidence from FISA surveillance, you can move to suppress it, arguing either that the information was unlawfully acquired or that the surveillance did not conform to the court’s authorization. When the Attorney General files a sworn declaration that disclosing the underlying FISA application would harm national security, the court reviews the materials in camera rather than in an adversary hearing. The judge decides whether the application established probable cause, whether the certification supporting it was properly made, and whether the government properly minimized collection touching U.S. persons. If the surveillance was unlawful, the evidence can be suppressed.10Office of the Law Revision Counsel. 50 U.S. Code 1805 – Issuance of Order In practice courts rarely grant these motions, because defense counsel cannot see what they would need to identify to attack.
Freezing the Money
Executive Order 13224, issued shortly after September 11, 2001, authorizes blocking all U.S.-based property and property interests of individuals and entities that commit, threaten, or support terrorism. It gives Treasury (through the Office of Foreign Assets Control) and State the power to designate targets for asset freezing.14The American Presidency Project. Executive Order 13224 – Blocking Property and Prohibiting Transactions With Persons Who Commit, Threaten to Commit, or Support Terrorism Designated names appear on OFAC’s Specially Designated Nationals list. U.S. persons are broadly barred from any transaction or dealing with anyone on it, including financial transfers, sales of goods or services, and indirect dealings such as processing a payment for someone else.
Sanctions penalties are steep. Civil penalties can reach $250,000 per violation or twice the value of the underlying transaction, whichever is greater. Willful violations are criminal offenses punishable by fines up to $1 million and up to 20 years in prison.15Office of the Law Revision Counsel. 50 USC 1705 – Penalties
Civil Suits by Victims
Anti-terrorism law also gives victims a direct route to compensation. Under 18 U.S.C. § 2333, any U.S. national injured in person, property, or business by an act of international terrorism can sue in federal district court and recover three times actual damages, plus attorney’s fees.16Office of the Law Revision Counsel. 18 U.S. Code 2333 – Civil Remedies The treble-damages structure works both as compensation and as deterrence, modeled on antitrust private enforcement.
These suits can also reach foreign governments. The Justice Against Sponsors of Terrorism Act of 2016 (JASTA) narrowed foreign sovereign immunity to allow civil claims against a foreign state for injuries or deaths caused by an act of international terrorism on U.S. soil. Before JASTA, sovereign immunity generally shielded foreign governments from such suits. The law has been used most prominently by families of September 11 victims in claims against Saudi Arabia, and JASTA litigation continues in federal courts.
What Expires Next
Some of the most intrusive powers carry sunset dates that force Congress back to the table. The original PATRIOT Act sunset 16 provisions, including roving wiretaps, business records orders, and the “lone wolf” provision.17U.S. Department of Justice. Report on USA PATRIOT Act Sunset Provisions The next big deadline is Section 702’s, on April 19, 2026. Whether Congress extends it, reshapes it, or lets it expire will be the most consequential surveillance debate of the current cycle. If you’re following the Anti-Terrorism Act’s trajectory, that’s the vote to watch.