U.S. terrorism laws work through two parallel tracks. Threats that originate or operate abroad run through formal designation lists, sanctions, and the material support statute, while threats inside the country are prosecuted under existing criminal laws boosted by a powerful sentencing enhancement. The dividing line, drawn in 18 U.S.C. § 2331, is geographic, and it shapes almost everything that follows: who can be listed, whose assets can be frozen, who can be sued, and how long a sentence can run.
How Federal Law Defines Terrorism
Section 2331 of Title 18 sets out two parallel definitions. Both international and domestic terrorism require violent acts, or acts dangerous to human life, that violate federal or state criminal law. Both also require that the acts appear intended to intimidate or coerce civilians, influence government policy through intimidation or coercion, or affect government conduct through mass destruction, assassination, or kidnapping.1Office of the Law Revision Counsel. 18 USC 2331 – Definitions
The split is geographic. International terrorism covers activity that occurs primarily outside the United States or crosses national borders. Domestic terrorism covers activity that occurs primarily within U.S. territory.1Office of the Law Revision Counsel. 18 USC 2331 – Definitions Nothing about the required conduct changes between the two. What changes is the toolkit prosecutors can reach for.
The Three Designation Tools
Federal designations work at three levels: organizations, individuals, and countries.
Foreign Terrorist Organizations
The Secretary of State can designate a group as a Foreign Terrorist Organization under section 219 of the Immigration and Nationality Act. The State Department currently lists around 93 FTOs.2United States Department of State. Foreign Terrorist Organizations Three conditions must be met: the group must be foreign, it must engage in terrorism or retain the capability and intent to do so, and its activities must threaten U.S. nationals or national security, including foreign relations and economic interests.
Once a group is designated, non-U.S. nationals who are members or representatives become inadmissible to the United States and removable if already here.3Office of the Law Revision Counsel. 8 USC 1189 – Designation of Foreign Terrorist Organizations Designations are reviewable: an organization can petition for revocation, and if the Secretary denies the petition, it has 30 days to challenge the decision in the U.S. Court of Appeals for the D.C. Circuit.
Specially Designated Global Terrorists
The Treasury Department’s Office of Foreign Assets Control uses a parallel tool that reaches individuals, businesses, and facilitators rather than organizations as such. Under Executive Order 13224, OFAC can list anyone who commits or poses a significant risk of committing acts of terrorism, or who supports those who do, as a Specially Designated Global Terrorist.4eCFR. 31 CFR Part 594 – Global Terrorism Sanctions Regulations
The SDGT designation is a financial weapon. All property and interests in property of a designated party that sit inside the United States, or that are in the possession or control of any U.S. person anywhere in the world, are frozen immediately. U.S. persons cannot transact with the designated party.4eCFR. 31 CFR Part 594 – Global Terrorism Sanctions Regulations
Violating OFAC terrorism sanctions carries its own penalties under the International Emergency Economic Powers Act. Civil penalties run up to the greater of $250,000 (adjusted for inflation under regulations to $377,700) or twice the value of the prohibited transaction. Willful violations can bring criminal fines up to $1,000,000 and up to 20 years in prison for individuals.5Office of the Law Revision Counsel. 50 USC 1705 – International Emergency Economic Powers Act Penalties
State Sponsors of Terrorism
The Secretary of State can place entire countries on the State Sponsors of Terrorism list if their governments have repeatedly supported international terrorism. Four countries currently carry the designation: Cuba, Iran, North Korea, and Syria.6United States Department of State. State Sponsors of Terrorism The consequences include a ban on U.S. foreign assistance, a prohibition on defense exports and sales, controls on dual-use exports, and various financial restrictions. Removing a country requires presidential certification to Congress that its government has fundamentally changed its leadership and policies, has not supported terrorism in the preceding six months, and has committed not to support terrorism in the future.7Office of the Law Revision Counsel. 22 USC 2371 – Prohibition on Assistance to Governments Supporting International Terrorism
Material Support: The Charge That Catches the Most People
The FTO designation’s sharpest teeth belong to the material support statute, 18 U.S.C. § 2339B. Anyone subject to U.S. jurisdiction who knowingly provides material support or resources to a designated FTO faces up to 20 years in prison. If a death results, the sentence rises to any term of years or life.8Office of the Law Revision Counsel. 18 USC 2339B – Providing Material Support or Resources to Designated Foreign Terrorist Organizations
“Material support” is defined broadly. It covers money, financial services, lodging, training, expert advice, weapons, explosives, transportation, false documents, communications equipment, and personnel. The only statutory carve-outs are medicine and religious materials.9Office of the Law Revision Counsel. 18 USC 2339A – Providing Material Support to Terrorists
That breadth catches people who think their contributions serve peaceful purposes. In Holder v. Humanitarian Law Project (2010), the Supreme Court upheld the statute against a First Amendment challenge, ruling that even training aimed at peaceful dispute resolution can free up an organization’s resources for violence. A defendant only needs to know that the organization is designated or engages in terrorism. No intent to further violence is required.10Library of Congress. Holder v Humanitarian Law Project, 561 US 1
Domestic Terrorism: No List, No Standalone Charge
Here the framework turns counterintuitive. Section 2331 defines domestic terrorism, but that definition is not itself a crime. No one is indicted for “domestic terrorism.” The federal government also maintains no public list of domestic terrorist organizations, and there is no domestic equivalent to FTO or SDGT designation.
The FBI investigates ideologically motivated criminal activity inside the United States, and prosecutors charge the specific conduct using existing federal statutes:
- Using, threatening, or attempting to use a biological, chemical, radiological, or explosive weapon against people or property in the United States carries any term of years to life, with the death penalty available when a death results.11Office of the Law Revision Counsel. 18 USC 2332a – Use of Weapons of Mass Destruction
- Violence against railroads, buses, ferries, or other mass transit carries up to 20 years, or life if a death results.12Office of the Law Revision Counsel. 18 USC 1992 – Terrorist Attacks and Other Violence Against Railroad Carriers and Against Mass Transportation Systems
- Federal explosives and arson statutes reach devices and fires that affect interstate commerce.
- Federal hate crime statutes apply when the violence is motivated by bias against a protected characteristic.
- Broad federal conspiracy charges cover agreements to commit any of the above.
The absence of a standalone charge does not mean lighter consequences. The sentencing enhancement below often closes the gap.
The Terrorism Sentencing Enhancement
Section 3A1.4 of the U.S. Sentencing Guidelines applies when a felony involved or was intended to promote a “federal crime of terrorism.” The enhancement increases the offense level by 12 levels, with a floor of level 32, and automatically sets the defendant’s criminal history category to the highest tier, Category VI.13United States Sentencing Commission. USSC Guidelines Manual 3A1.4 – Terrorism
The practical effect is dramatic. A first-time offender is treated as though their record were the most extensive possible. Offense level 32 at Category VI produces a recommended sentence starting at 210 months, roughly seventeen and a half years, before any other adjustments. An underlying conspiracy or property-destruction count that might otherwise carry a few years can multiply several times over.
Civil Remedies for Terrorism Victims
Criminal prosecution and sanctions are not the only consequences. U.S. nationals injured by international terrorism can sue in federal court under 18 U.S.C. § 2333 and recover triple their actual damages plus attorney’s fees. The provision reaches injuries to a person’s body, property, or business.14Office of the Law Revision Counsel. 18 USC 2333 – Civil Remedies
These suits reach beyond the attackers themselves. Under subsection (d), anyone who aided and abetted an act of international terrorism by knowingly providing substantial assistance, or who conspired with the attacker, faces civil liability, provided the responsible organization was a designated FTO at the time of the attack.14Office of the Law Revision Counsel. 18 USC 2333 – Civil Remedies Banks, charities, and businesses that funneled money to designated groups have faced multimillion-dollar judgments under this provision.
Suing Foreign Governments
Foreign governments normally enjoy sovereign immunity in U.S. courts. The Justice Against Sponsors of Terrorism Act, enacted in 2016, carved out an exception. JASTA allows U.S. nationals to sue a foreign government for physical injury, property damage, or death occurring in the United States when caused by an act of international terrorism, whether or not that country sits on the State Sponsors of Terrorism list. The foreign government’s tortious acts do not have to have occurred on U.S. soil; only the resulting harm does.
Victim Expense Reimbursement
U.S. nationals who are victims of international terrorism can also seek reimbursement through the International Terrorism Victim Expense Reimbursement Program, administered by the Department of Justice. The program covers medical expenses up to $50,000, funeral and burial costs up to $25,000, mental health care up to $5,000, property loss up to $10,000, and miscellaneous expenses such as emergency travel up to $15,000. It does not cover lost wages, pain and suffering, or attorney’s fees. Reimbursement is denied if the victim was criminally involved in the terrorist act, and may be reduced for grossly reckless conduct or for acting as a mercenary.15eCFR. 28 CFR Part 94 Subpart A – International Terrorism Victim Expense Reimbursement Program The program is limited to international terrorism; victims of domestic incidents look to other federal and state victim-compensation programs.