Another Lawsuit, This Time in Colorado, Over Trump’s Use of the Alien Enemies Act

The American Civil Liberties Union filed another lawsuit on Monday seeking to stop the Trump administration from using a powerful wartime statute to deport to El Salvador immigrants from Venezuelan who have been accused of being violent gang members.

The lawsuit, brought in Federal District Court in Colorado, was the third of its kind filed in recent days, joining similar legal challenges that were filed last week in Texas and New York.

Lawyers for the A.C.L.U. brought the suit on behalf of two men — known in court papers only by the their initials, D.B.U. and R.M.M. The men claim they have been wrongly accused by the administration of being members of the Venezuelan gang, Tren de Aragua.

Court papers say that D.B.U., 32, was arrested on Jan. 26 at a gathering that federal drug and immigration agents have repeatedly described as a Tren de Aragua party. After his arrest, the papers say, he denied being a member of the gang and has not been charged with any crime.

Federal agents arrested R.M.M., 25, last month after they saw him standing with three other Hispanic men near their vehicles outside a residence in Colorado that was under surveillance as part of an investigation into Tren de Aragua, court papers said.

R.M.M. has claimed that he had nothing to do with the gang and had gone to the location with friends “to meet a prospective buyer for his vehicle at a public meeting,” the papers said.

Mr. Trump’s efforts to use the Alien Enemies Act to deport scores of Venezuelan immigrants have set off one of the most contentious legal battles of his second term. It began last month, after the president invoked the act, which has been used only three times since it was passed in 1798, to authorize the deportation of people he claimed were members of Tren de Aragua.

The A.C.L.U. immediately began fighting Mr. Trump’s use of the act, which the administration has already employed to deport more than 100 Venezuelan immigrants to the CECOT megaprison in El Salvador, known for its human rights violations.

The initial challenge by the A.C.L.U. was brought in Washington, where a federal judge, James E. Boasberg, issued an order to temporarily stop the deportation flights to El Salvador. Judge Boasberg expressed concern that the immigrants who fell subject to Mr. Trump’s proclamation had no way to contest whether they were gang members in the first place.

A federal appeals court in Washington subsequently agreed with him, finding that, at this early stage, it appeared unlikely that the Alien Enemies Act could be applied as Mr. Trump was trying to use it.

Then last week, the Supreme Court weighed in, ruling that immigrants subject to deportation under the act needed to be given notice before being removed from the country so that they could challenge the process in court. But those challenges, the justices said, were required to be made in the places where the immigrants were being held.

That prompted the A.C.L.U. to scramble to locate any Venezuelans who might be subject to Mr. Trump’s proclamation. They have so far located immigrants in Texas, New York and Colorado and the lawsuits filed on their behalf were temporary measures meant to keep them in the country until the underlying legal questions involving the administrations use of the Alien Enemies Act were resolved.