Broadening their efforts to stop the Trump administration from using a rarely invoked wartime statute to carry out deportations, lawyers for the American Civil Liberties Union on Wednesday asked a federal judge in Texas to bar the White House from using the law to send Venezuelan migrants to El Salvador.
The filings by the A.C.L.U., submitted in Federal District Court in Brownsville, Texas, were in direct response to a Supreme Court decision on Monday. That ruling permitted the migrants to challenge efforts to deport them under the wartime law, known as the Alien Enemies Act, but only in the place they were being held.
The three Venezuelans identified in the Texas filings — albeit only by their initials — had already secured a court order from a federal judge in Washington last month shielding them from being flown to El Salvador under President Trump’s invocation of the act. But the Supreme Court, in its ruling, vacated the order by that judge, James E. Boasberg, saying that the A.C.L.U.’s case on behalf of the men should have been filed in Texas, not Washington.
On Tuesday, the A.C.L.U. filed a similar case in New York, noting that two of the Venezuelans subject to Mr. Trump’s proclamation had been moved from a detention center in Texas to one in the town of Goshen, in Orange County, N.Y.
At an emergency hearing Wednesday morning in Federal District Court in Manhattan, Judge Alvin K. Hellerstein followed the path laid out by Supreme Court and declined, for the moment, to decide whether Mr. Trump was correctly using the Alien Enemies Act.
But Judge Hellerstein also said he would order the government to alert anyone who was targeted for removal in the Southern District of New York to give them an opportunity for a hearing to question whether they had been improperly identified as a gang member.
Mr. Trump’s efforts to use the Alien Enemies Act to deport scores of Venezuelan migrants has 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 claims were members of Tren de Aragua, a violent Venezuelan street gang.
The A.C.L.U. immediately challenged Mr. Trump’s use of the act in court filings in Washington, even as the administration rushed more than 100 Venezuelan migrants on to planes to El Salvador. Once there, they were put in a megaprison called CECOT, known for its brutal conditions.
Lawyers for the A.C.L.U. have said the government unlawfully used the act, which is supposed to be invoked only in times of declared war or during an “invasion” by a foreign nation or government.
In its ruling this week, the Supreme Court did not weigh in on the question of whether Mr. Trump has complied with such provisions of the law. But a federal appeals court in Washington ruled last month that at this early stage it appeared unlikely that the Alien Enemies Act could be applied in the way Mr. Trump was trying to use it.
Judge Boasberg has also expressed skepticism about the White House’s use of the statute, saying he was concerned that the migrants who fell subject to it had no way to contest whether they were gang members in the first place.
One of the men identified in the Texas filing as J.A.V. is a 32-year-old Venezuelan who was taken into custody by federal immigration agents during an asylum interview in February, largely because of his tattoos, court papers say. He has denied being a member of Tren de Aragua.
J.A.V.’s lawyers claim he is H.I.V.-positive and fears deportation to El Salvador “on account of his sexual orientation.” Like the other two men identified in the filings, he was almost deported on the planes that left Texas on March 15, but was spared at the last minute by Judge Boasberg’s initial order.
Both of the other men — known in the filings as J.G.G. and W.G.H. — have also denied belonging to Tren de Aragua.
Jonah E. Bromwich contributed reporting.
