Escalating a standoff with the federal judiciary, the Trump administration invoked national security secrecy powers on Monday night to avoid complying with a judge’s demand for information about its transfer of migrants to a prison in El Salvador despite a court order.

The administration, as justification, pointed to the so-called state secrets privilege. Here is a closer look at the scope and limits of that power and the unfolding confrontation between two branches of government.

What information does the judge want?

The judge is asking for basic data about two flights by an Immigration and Customs Enforcement contractor on Saturday, March 15.

The flights took detained Venezuelan migrants from Texas to El Salvador after President Trump issued a proclamation invoking a wartime deportation law to assert the power to summarily remove people the government suspects of being members of a gang, Tren de Aragua, without individual due process hearings.

The judge has asked the following questions: “1) What time did the plane take off from U.S. soil and from where? 2) What time did it leave U.S. airspace? 3) What time did it land in which foreign country (including if it made more than one stop)? 4) What time were individuals subject solely to the proclamation transferred out of U.S. custody? and 5) How many people were aboard solely on the basis of the proclamation?”

Why is he seeking these details?

The judge is trying to assess whether administration officials violated a court order, and if so what the consequences — like whether to find them in contempt — should be.

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