Trump Signs Proclamation 10903 Invoking 1798 Alien Enemies Act Against Tren de Aragua

On March 14, 2025, President Trump signed Proclamation 10903, “Invocation of the Alien Enemies Act Regarding the Invasion of The United States by Tren De Aragua,” declaring that the Venezuelan prison-gang network constituted a “foreign nation or government” engaged in “invasion or predatory incursion” against US territory — the statutory predicates for invoking the 1798 Alien Enemies Act (50 U.S.C. §§ 21-24).

The proclamation’s legal-architecture significance. The Alien Enemies Act is a wartime statute, last used at scale during World War II for the internment and removal of Japanese, German, and Italian nationals. It authorizes the president, during declared war or “invasion or predatory incursion” by a foreign nation, to detain and remove all nationals 14 or older of the hostile power, without the due-process protections that apply to immigration proceedings under the Immigration and Nationality Act.

The Trump administration’s invocation outside a declared war — designating a non-state criminal organization as a “foreign nation” — is the first such use since WWII. The legal theory was developed by DOJ Civil Division and OLC; Stephen Miller has been publicly identified as the principal policy architect. Secretary of State Marco Rubio had designated Tren de Aragua as a Foreign Terrorist Organization on February 20, 2025, supplying the predicate for the Proclamation.

The Posse Comitatus dimension. The Proclamation routes federal detention-and-removal operations through wartime-detention legal framing rather than immigration-enforcement framing. Wartime detention of foreign enemies is structurally outside the Posse Comitatus Act’s reach — the Act regulates use of federal military for domestic law enforcement, not for wartime national-security operations. By reclassifying a removal operation as wartime detention, the administration accessed kinetic federal capacity (military-base detention, military air transport, military coordination with foreign-government partners like El Salvador’s CECOT prison) without invoking the Insurrection Act or amending Posse Comitatus.

This is one of twelve enumerated carve-outs in the 2024-2026 reclassification architecture documented in the posse-comitatus-reclassification-map mechanism note.

Immediate operational consequences. Within hours of the Proclamation, the administration removed more than 200 Venezuelan nationals to El Salvador’s CECOT (Centro de Confinamiento del Terrorismo) prison, in cooperation with Salvadoran President Nayib Bukele. The flights departed before US District Judge James Boasberg’s TRO took effect on March 15, 2025; Boasberg’s subsequent order directing planes already in the air to turn around was not complied with by the administration.

Subsequent litigation. A federal judge in Pennsylvania ruled on May 14, 2025 that the administration could use the Alien Enemies Act to deport specific individuals shown to be Tren de Aragua members. In September 2025, however, an appellate court ruled more broadly that Tren de Aragua does not constitute a “foreign nation” engaged in “invasion” under the statute’s terms, defining invasion as “an act of war involving the entry into this country by a military force of or at least directed by another country or nation, with a hostile intent.” The litigation remains active.

Structural significance. Proclamation 10903 establishes the precedent — and the legal theory — for redesignating transnational criminal organizations as “foreign nations” engaged in “invasion” so that wartime carve-outs to Posse Comitatus and due-process protections attach. Once the architecture exists, it can be reused: any organization the executive designates and any incursion the executive characterizes as predatory becomes a vehicle for wartime-detention authority over US-residing populations. This is the foreign-enemy-detention category in the broader posse-comitatus-reclassification-map enumeration.

Sources

• White House Proclamation 10903 (March 14, 2025): https://www.whitehouse.gov/presidential-actions/2025/03/invocation-of-the-alien-enemies-act-regarding-the-invasion-of-the-united-states-by-tren-de-aragua/
• Immigration Policy Tracking Project on Proclamation 10903: https://immpolicytracking.org/policies/proclamation-invocation-of-the-alien-enemies-act-regarding-the-invasion-of-the-united-states-by-tren-de-aragua/
• NPR: “Federal judge blocks Trump hours after he issues ‘alien enemies’ action” (March 15, 2025): https://www.npr.org/2025/03/15/nx-s1-5246028/trump-alien-enemies-act-tren-de-aragua-deportation
• FactCheck.org: “Q&A on the Alien Enemies Act and Tren de Aragua in the U.S.” (March 2025): https://www.factcheck.org/2025/03/qa-on-the-alien-enemies-act-and-tren-de-aragua-in-the-u-s/
• PolitiFact: “Why did a court rule that Trump can’t deport Tren de Aragua members using the Alien Enemies Act?” (Sept 3, 2025): https://www.politifact.com/article/2025/sep/03/Tren-de-Aragua-deportations-Alien-Enemies-Trump/
• NPR: “Federal judge OKs use of Alien Enemies Act to deport Venezuelans” (May 14, 2025): https://www.npr.org/2025/05/14/nx-s1-5397833/judge-alien-enemies-act-venezuelans-pennsylvania
• CRS LSB11269: “The Alien Enemy Act: History and Potential Use to Remove Members of International Criminal Cartels”
• Van Der Hout LLP analysis on due-process concerns: https://www.vblaw.com/trump-issues-executive-order-invoking-alien-enemies-act-against-tren-de-aragua-raising-serious-due-process-concerns/

Cross-references

• posse-comitatus-reclassification-map — carve-out #7 (Alien Enemies Act / wartime detention)
• privatization-of-force-projection-one-50-year-arc-four-phases — Phase-4 substrate