The pardon marks a stunning epilogue to a story of Bush administration intrigue, as Libby was a central figure in attempts to discredit reports that the government manipulated intelligence in order to justify the invasion of Iraq.

"I don't know Mr. Libby," Trump said in a statement released by the White House press secretary. "But for years I have heard that he has been treated unfairly. Hopefully, this full pardon will help rectify a very sad portion of his life."

But it also comes amid an FBI investigation into the Trump administration, and attempts by Trump and his allies to discredit former FBI director James Comey — who was the Justice Department official with oversight over the Libby case in 2005. Comey, who was fired by Trump last year, has just written a book calling Trump "unethical and untethered to truth."