President Donald Trump declared Friday the Department of Justice should try to identify the writer of a bitingly critical New York Times opinion piece, purportedly submitted by a member of an administration “resistance” movement straining to thwart his most dangerous impulses.

Trump cited “national security” in an interview with reporters aboard Air Force One as he called on Attorney General Jeff Sessions to open an investigation to unmask the author. He also said he was exploring the potential of bringing legal action against the newspaper over the publication of the essay two days earlier.

“Jeff should be investigating who the author of that piece was because I really believe it’s national security,” Trump said. If the person has a high- level security clearance, he said, “I don’t want him in those meetings.”

It’s all but unthinkable that the Justice Department could open an investigation into the op-ed article. Though it was strongly critical of Trump, no classified information appears to have been revealed by the author or leaked to the newspaper, which would be one crucial bar to clear before a leak investigation could even be contemplated.

Still Trump’s call is the latest test of the independence of the Justice Department, which is supposed to make investigative and charging decisions without political interference from the White House.

A day earlier, Trump’s top lieutenants stepped forward to repudiate the op-ed in a show of loyalty to their incensed boss, who has ordered aides to unmask the writer.

In an interview Thursday with Fox News, Trump said the author “may not be a Republican, it may not be a conservative, it may be a deep state person who has been there for a long time.”