Trump’s use of Alien Enemies Act ruled illegal by appeals court

The Fifth Circuit Court of Appeals has blocked President Donald Trump’s use of the 1798 Alien Enemies Act against Venezuelan gang members, delivering the first appellate ruling to declare the administration’s wartime authority illegal during peacetime.

Catch up: Trump first activated the Alien Enemies Act against suspected Tren de Aragua (TdA) members in March, saying they were conducting “irregular warfare,” undertaking hostile actions and engaging in mass illegal migration to the U.S. The law, which was last used during World War II, authorized the incarceration of 120,000 Japanese Americans in concentration camps that subjected them to poor food, unsanitary conditions and harsh treatment. Before courts intervened, authorities transported at least 250 suspected gang members to El Salvador.

The ruling: By a 2-1 vote on Sept. 2, the Fifth Circuit, one of the country’s most conservative appeals courts, found that Trump’s allegations do not satisfy legal standards for “invasion” or “predatory incursion.” Republican-appointed Judge Leslie Southwick concluded that invasion requires “military action by a foreign nation,” while predatory incursion demands “hostile intent.”

The majority also dismissed claims that immigration flows equal “an armed, organized force to occupy, to disrupt or to otherwise harm the United States.” Trump nominee Andrew Oldham, however, countered with 130 pages supporting the president’s “unreviewable power” to detain or deport non-citizens anytime.

Why this matters: The decision establishes the first appellate precedent limiting presidential emergency powers absent genuine warfare. Without judicial oversight, the law could allow presidents to detain or deport non-citizens whenever they want, as long as they cite an “invasion” regardless of actual threats. That being said, the ruling shields not only Venezuelan migrants, but all foreign nationals including permanent residents, from detention without proper legal justification. Still, there are fears of a constitutional crisis given the Trump administration’s apparent defiance of court orders.

The case will likely reach the Supreme Court for a final ruling.