The ruling, applying only to detainees held in western Pennsylvania, is the first to uphold the president’s invocation of the wartime act. But it requires that detainees be given 21 days’ notice.

This is the second time in a week that a federal judge has blocked the administration from sending Venezuelans to the Salvadoran prison under the 18th-century wartime law.

U.S. District Judge Stephanie L. Haines, who was nominated by President Donald Trump, is the first judge to back the Trump’s use of the 1798 Alien Enemies Act.