James Clapper, the mendacious national intelligence director who last month told NBC News that he gave the “least untruthful answer” in a March Senate hearing about the extent of government spying on U.S. citizens revised that assessment to “erroneous” Tuesday.

The most senior intelligence officer in the country wants Americans to believe he suffered a memory lapse when he gave the answer to Oregon Sen. Ron Wyden. Wyden had asked Clapper, “Does the NSA collect any type of data at all on millions or hundreds of millions of Americans?” Clapper responded, “No, sir … not wittingly.”

Clapper wrote in letter to the Senate Intelligence Committee published Tuesday that he “simply didn’t think” of the NSA programs of dragnet phone surveillance when he testified in March that the agency did “not wittingly” spy on Americans’ communications. He said “his staff acknowledged the error to Senator Wyden’s staff soon after the hearing,” and that he “can now openly correct it because the existence” of a portion of the government’s surveillance program “has been declassified.”

Portions of the letter were reported by The Washington Post on Monday.

— Posted by Alexander Reed Kelly.