A Trump-appointed federal judge has permanently blocked the Trump administration from detaining, transferring or removing Venezuelans targeted for deportation under the Alien Enemies Act in the Southern District of Texas — ruling that the administration’s invocation of the AEA “exceeds the scope” of the law.

The ruling marks the first time a federal judge has declared President Donald Trump’s use of the Alien Enemies Act unlawful, with the judge rebuking the president’s claim that the Venezuelan criminal gang Tren de Aragua is invading the United States.

The ruling, by U.S. District Judge Fernandez Rodriguez, only applies to AEA-based deportations and does not prevent the government from detaining or seeking the deportation of individuals under the Immigration and Nationality Act.

In a 36-page opinion, Judge Rodriguez concluded that Trump’s March 15 invocation of the Alien Enemies Act is “unlawful” and “exceeds the scope” of the centuries-old wartime law that allows the president to deport noncitizens with little-to-no due process during an invasion or predatory incursion.

“The President cannot summarily declare that a foreign nation or government has threatened or perpetrated an invasion or predatory incursion of the United States, followed by the identification of the alien enemies subject to detention or removal,” Judge Rodriguez wrote.

While the judge declined to weigh in on whether Tren de Aragua represents a foreign nation or government, he concluded that the Trump administration fell short of proving the violent gang was engaging in an “invasion” or “predatory incursion” as required by the Alien Enemies Act.

Trump’s proclamation had alleged that Tren de Aragua was a “hybrid criminal state” invading the United States. Though Trump’s proclamation claimed that Tren de Aragua members “harmed lives” in the U.S., it did not provide any evidence to suggest the gang did so in an “organized armed attack,” according to Judge Rodriguez.

“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.

Lee Gelernt, the lawyer who argued the case for the American Civil Liberties Union, lauded the ruling.

“Critically, the court properly ruled that the president lacks authority simply to declare that there’s been an invasion of the U.S. and then invoke an 18th century wartime authority during peacetime,” Gelernt told ABC News. “Congress never meant for this law to be used in this manner.”

Judge Rodriguez, in his ruling, also pushed back against the Trump administration’s claim that the president’s use of the Alien Enemies Act should not be reviewed by courts — a claim the DOJ lawyers have asserted in courthouses across the country as they fight a series of challenges to Trump’s use AEA.

“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.

While other judges have temporarily blocked the Trump administration’s use of the Alien Enemies Act, most have done so on an emergency basis without weighing in on the “merits” or lawfulness of the proclamation. Judge Rodriguez’s lengthy order marks the first time a federal judge has plainly declared the proclamation unlawful and blocked him from using it to deport noncitizens.

The Trump administration touched off a legal battle in March when it invoked the Alien Enemies Act to deport two planeloads of alleged migrant gang members to the CECOT mega-prison in El Salvador by arguing that the Venezuelan gang Tren de Aragua is a “hybrid criminal state” that is invading the United States.

An official with the U.S. Immigration and Customs Enforcement acknowledged that “many” of the men deported on March 15 lack criminal records in the United States — but said that “the lack of specific information about each individual actually highlights the risk they pose” and “demonstrates that they are terrorists with regard to whom we lack a complete profile.”

The U.S. Supreme Court, in a subsequent 5-4 decision, lifted an injunction issued by a federal judge in Washington, D.C., that had halted deportations under the AEA — but said detainees must be given due process to challenge their removal in the district where they were detained.