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Joint Chiefs Chair Gen. Mark Milley was so convinced that then-President Donald Trump had gone into "serious mental decline" after the Capitol riot that he took steps to limit him from going "rogue" and launching nuclear weapons, a new book by Bob Woodward reportedly reveals.

Peril, an upcoming book written by Woodward and Washington Post journalist Robert Costa, reports that after the Jan. 6 attack on the Capitol, Milley secretly called a meeting at the Pentagon and instructed officials not to take orders to launch nuclear weapons unless he was involved, according to CNN. 

"No matter what you are told, you do the procedure," he reportedly told them. "You do the process. And I'm part of that procedure."

Milley reportedly then went around the room to ask the officials to confirm they understood this. He was worried Trump might "go rogue" and "certain that Trump had gone into a serious mental decline in the aftermath of the election, with Trump now all but manic, screaming at officials and constructing his own alternate reality about endless election conspiracies," the book reportedly says.

At one point after the Capitol riot, Milley reportedly had a phone call with House Speaker Nancy Pelosi (D-Calif.), during which she questioned him about whether there was "anybody in charge at the White House who was doing anything but kissing [Trump's] fat butt" and said the president is "crazy." Milley reportedly responded, "Madam Speaker, I agree with you on everything."

The book also reveals Milley held secret phone calls with his Chinese counterpart to assure him the United States wouldn't strike the country, The Washington Post reports. Another revelation in the book, according to CNN, is a description of a tense meeting in the Oval Office, during which Trump reportedly told then-Vice President Mike Pence that if he didn't take steps to overturn the election, "I don't want to be your friend anymore."