WASHINGTON — The Trump administration is invoking a powerful tool in seeking to cut off a judge’s inquiry into whether it defied his order to turn around planes carrying Venezuelan migrants who were being deported from the United States.

The Justice Department said in court papers Monday that it was invoking the “state secrets privilege” in refusing to provide details demanded by U.S. District Judge James Boasberg about flights that carried the migrants to El Salvador earlier this month.

The claim often functions as a prevailing legal authority that has been used to limit or file lawsuits against the government when it says military or national security interests are at risk.

In 2022, the Supreme Court dismissed a lawsuit filed by a detainee at Guantanamo Bay who was captured after the Sept. 11 attacks and tortured by the CIA abroad. The court agreed with the government’s invocation of “state secrets” and ruled that information about the treatment of the detainee, Abu Zubaydah, must remain secret even though much of it has been widely reported.

The legal doctrine has its roots in a contract between President Abraham Lincoln and a spy for the Union during the Civil War.

After the spy’s estate sued for money owed for his wartime service, the Supreme Court ruled in 1876 that some subject matters, including involving espionage, are so sensitive that courts have no business even hearing lawsuits.

During the Cold War, the court also declared that some pieces of evidence sought in lawsuits must remain secret.

After their husbands died in the crash of a B-29 bomber, three widows sued for the accident report. In 1953, the justices allowed the executive branch to withhold, even from the court, details about the crash because officials said it was on a secret mission to test new equipment.

The current case began when President Donald Trump invoked a rarely used 18th century law, the Alien Enemies Act, to enable the quick deportation of Venezuelan migrants who were declared to be members of the Tren de Aragua gang.

Boasberg, the chief judge of the federal district court in Washington, held an emergency hearing after lawyers for some migrants who feared deportation sued. The judge forbade any additional deportations and ordered “that any plane containing these folks that is going to take off or is in the air needs to be returned to the United States.”

Even as the administration appeals the entirety of Boasberg’s order, the dispute is over its compliance with the judge’s command.

Boasberg had asked for details about the flights, including when the planes took off and landed, and how many people were aboard.

The administration said Monday it would not answer his questions. Disclosure of the information, even just to Boasberg in a secure setting, “would cause significant harm to the foreign relations and national security interests of the United States,” Attorney General Pam Bondi wrote in a court filing.

Boasberg is more accustomed to dealing with sensitive national security information than most federal judges. He previously served as the presiding judge of the secretive court that reviews government surveillance programs.

He told government lawyers at one hearing that they could file their answer “under seal,” meaning not for public disclosure. He also said he would look at any sensitive information in the courthouse’s security facility known as a SCIF.

But the administration told the judge that his review of the material in any setting is unnecessary and inappropriate.

It’s true that administration officials recirculated a posting from Salvadoran President Nayib Bukele after Boasberg’s initial order. “Oopsie…Too late,” Bukele wrote on X. Secretary of State Marco Rubio tweeted that the U.S. had sent more than 250 people to El Salvador.

But courts have held that public comments do not always amount to official confirmation of the same information. That is what the Supreme Court decided in the Zubaydah case, over a dissent by Justice Neil Gorsuch.

“Nothing in the case suggests that requiring the government to acknowledge what the world already knows to be true” would endanger national security, Gorsuch wrote, joined by Justice Sonia Sotomayor.

Indeed, despite Rubio’s post, the Justice Department wrote, “Official confirmation of any of those allegations would pose a distinct threat to foreign relations and national security.”

Critics of the use of the state secrets claim say it often is an effort to prevent embarrassing revelations.

“That’s probably what’s happening here,” Shayana Kadidal, a human rights lawyer who has challenged state secrets assertions, wrote in an email. “They let the flights leave despite knowing full well that the judge had ordered them turned around, and are doing this to avoid a contempt finding.”

The administration thinks so. It cited the Supreme Court’s decision last year that gave presidents broad immunity from prosecution for official actions and helped Trump avoid a criminal trial on charges of interference with the 2020 election.

The president’s ”execution of his Article II duties — which ‘are of unrivaled gravity and breadth’ and include ‘managing matters related to terrorism . . . and immigration’ — requires the ‘utmost discretion and sensitivity,’” the Justice Department wrote.

The Supreme Court has told judges to assess whether the government’s claim is appropriate.

In practice, when Cabinet-level officials assert that state secrets are at risk, as they have in the current case, judges often comply.

“Basically as long as they can get a cabinet official to sign off (personally) to a declaration, game over,” Kadidal wrote.