A federal district judge ruled Thursday that the Alien Enemies Act (AEA) does not permit President Trump to swiftly deport alleged Venezuelan gang members to a prison in El Salvador, extending a block on the law being used against migrants detained in South Texas. 

U.S. District Judge Fernando Rodriguez Jr., a Trump appointee, said the rarely used law can only be invoked when an “organized, armed force” is entering the United States, rejecting the president’s claims that he can use it against alleged members of the Venezuelan gang Tren de Aragua (TdA).

The ruling from Rodriguez offered a historical deep dive into the rarely used statute used just three times prior in U.S. history, and all during times of war while parsing terms central to igniting the power. 

Rodriguez determined Trump’s efforts to use the law to deport alleged gang members strayed from the strict war powers, writing that Trump’s invocation “exceeds the scope of the statute and, as a result, is unlawful.”

“The Proclamation makes no reference to and in no manner suggests that a threat exists of an organized, armed group of individuals entering the United States at the direction of Venezuela to conquer the country or assume control over a portion of the nation. Thus, the Proclamation’s language cannot be read as describing conduct that falls within the meaning of ‘invasion’ for purposes of the AEA,” he wrote. 

“While the Proclamation references that TdA members have harmed lives in the United States and engage in crime, the Proclamation does not suggest that they have done so through an organized armed attack, or that Venezuela has threatened or attempted such an attack through TdA members. As a result, the Proclamation also falls short of describing a ‘predatory incursion.’” 

Trump’s use of the Alien Enemies Act has become a flash point in the administration’s sweeping immigration efforts of its first 100 days. The Trump administration deported more than 100 men to a Salvadoran megaprison, often citing their tattoos as evidence of gang affiliation and without giving the men any formal process for refuting the claims. 

Thursday’s ruling marks a significant legal victory for the American Civil Liberties Union (ACLU), which has filed a wave of class action lawsuits in judicial districts across the country on behalf of detained migrants.

It’s also a sign of potential difficulty for the Trump administration as the Supreme Court mulls whether to lift its current block on deportations under the Aliens Enemies Act as it weighs whether to leapfrog the lower courts and provide a nationwide resolution on questions over his power. 

Rodriguez is one of several federal judges who temporarily blocked Alien Enemies Act deportations in their districts as the challenges proceed. But Thursday’s ruling marks the first time that a judge has entered their final judgment in one of the cases. 

The 1798 Alien Enemies Act enables migrants to be summarily deported amid an “invasion” or “predatory incursion” by a foreign nation. The law was previously invoked during the War of 1812, World War I and World War II, most recently used as the basis for Japanese internment. The ACLU has asserted the law can only be used in times of war. 

Rodriguez did not adopt that position fully. But he ruled that Trump stretched the law too far, saying it must “involve an organized, armed force entering the United States to engage in conduct destructive of property and human life in a specific geographical area.” 

The judge also rejected the administration’s other arguments, including that the courts have no authority to review the president’s invocation of the law.

“Allowing the President to unilaterally define the conditions when he may invoke the AEA, and then summarily declare that those conditions exist, would remove all limitations to the Executive Branch’s authority under the AEA, and would strip the courts of their traditional role of interpreting Congressional statutes to determine whether a government official has exceeded the statute’s scope. The law does not support such a position,” he wrote.

Rodriguez also delivered another key victory to the ACLU, agreeing to class certification for all would-be deportees In the Southern District of Texas, averting a scenario in which each would have to file their own petition to fight their removal.