Tren de Aragua and the Use of Military Force

On Sept. 19, 2025, the Congressional Study Group on Foreign Relations and National Security convened over Zoom to discuss the legal questions raised by recent U.S. military strikes against alleged members of Tren de Aragua. Earlier that month, the U.S. military used lethal force against 11 alleged members of the Venezuelan criminal organization—which the United States has designated as a terrorist organization—who were said to be smuggling narcotics into the United States. A second strike against another vessel similarly alleged to be smuggling narcotics on behalf of the group soon followed, with the administration suggesting that more would come. These incidents raised a host of difficult questions under both domestic and international law, as well as broader concerns about how they intersect with longstanding U.S. use-of-force policies.

For the session, the study group was joined by three leading experts, whom coordinator Scott R. Anderson led in an initial discussion:

• Brian Finucane, a senior advisor at the International Crisis Group and a former attorney-adviser at the U.S. Department of State;
• Todd Huntley, director of the National Security Law Program at Georgetown University Law Center, who previously spent more than 20 years as a judge advocate general in the U.S. Navy with extensive operational law experience supporting the special operations community; and
• Loren Voss, a public service fellow at Lawfare and a reserve U.S. Air Force officer who has held several relevant government positions, including as director for defense policy and strategy at the National Security Council under the Biden and Trump administrations.

Background readings circulated before the session included:

• Brian Finucane, “Legal Issues Raised by a Lethal U.S. Military Attack in the Caribbean,” Just Security (Sept. 3, 2025);
• “Lawfare Live: U.S. Military Conducts Lethal Strike on Venezuelan ‘Drug Boat’,” Lawfare (Sept. 4, 2025) (livestream and podcast);
• Scott R. Anderson, “Did the President’s Strike on Tren de Aragua Violate the Law?,” Lawfare (Sept. 5, 2025); and
• Brian Finucane, “Asserting a License to Kill: Why the Caribbean Strike is a Dangerous Departure from the ‘War on Terror’,” Just Security (Sept. 15, 2025).

Huntley opened the operational discussion by describing what one would normally expect to see in advance of a military strike of this kind, from the targeting process to the layers of review involved, while also explaining the role that judge advocates play in vetting proposed operations for legal sufficiency. Voss elaborated on how decisions are made in the run-up to a particular strike, including how targets are developed and approved. Against that baseline, the speakers noted, the Caribbean strikes appeared to depart in significant ways from the deliberative processes that ordinarily accompany the use of lethal force, raising questions about the legal theories on which the administration was relying.

Turning to international law, Finucane walked through the “jus ad bellum” questions the strikes presented. He examined whether the operations could be characterized as an armed attack against another state implicating the prohibition on the use of force in Article 2(4) of the U.N. Charter, whether a strike in international waters changes that analysis, and how concepts such as the passive personality principle bear on it. He then addressed whether the strikes could be justified as a lawful exercise of self-defense—asking whether Tren de Aragua had carried out an armed attack on the United States and, even assuming it had, whether a lethal response would satisfy the requirements of necessity and proportionality. Huntley described how the U.S. military approaches jus ad bellum determinations as an institutional matter.

The conversation then moved to jus in bello questions and the competing theories that might apply. Huntley considered the possibility that Tren de Aragua is a non-state group engaged in a non-international armed conflict with the United States, and whether, under this theory, the individuals targeted would have been permissible military objectives. Voss laid out an alternative framing of the operations as one-off self-defense strikes, and what that characterization would mean for who could lawfully be targeted. Finucane questioned whether there was any colorable case that the strikes complied with international human rights law, and how the U.S. military has historically envisioned that body of law’s applicability to operations of this nature.

On domestic law, the speakers canvassed the constitutional and statutory landscape. Voss addressed the scope of the president’s Article II authority, while Finucane discussed statutory restrictions such as the war powers resolution as well as the longstanding assassination ban, and Anderson examined the self-defense rationale and the relevant federal criminal statutes. Huntley addressed the implications under the Uniform Code of Military Justice, including for service members ordered to carry out such strikes. The group closed by considering slippery-slope concerns—among them the targeting of migrants and the potential geographic expansion of such operations—and the possible constraints available, including litigation, the military chain of command and the doctrine of unlawful orders, congressional action through joint war powers resolutions and other measures, and enhanced oversight and transparency mechanisms such as sensitive military reporting requirements, the legal policy framework report, and the use of confirmations as leverage.

The session then concluded with an open discussion wherein attendees were invited to ask questions or present their own views on some of the issues raised.

All sessions of the study group operate under the Chatham House Rule, meaning statements made there are not for attribution without the permission of the speaker.