"In short, it comes down to one person: Milley," Costa tweeted. "Trump loathed his coverage in press, in books, per multiple sources. As Trump fumed in post-presidency period about Milley, in his view, being cast as a hero and himself as an insurrectionist, he began to talk regularly about Milley in 2021, dismissing him and bringing up stories that made Milley seem unintelligent and untrustworthy, per sources."
The ex-president's efforts to discredit the chairman of the Joint Chiefs of Staff caused him to act in a way that alarmed some of his aides.
"Trump’s anger about Milley led him to be cavalier about what he said about Milley and their interactions & policy decisions, and it frustrates some aides who notices how he would veer into dicey/near classified material in convos," Costa said. "Then Trump started to do interviews for books."
Costa said the former president did not speak to him or Washington Post reporter Bob Woodward for their book, Peril, but Trump spoke to others during that same period and frequently bashed Milley both in those conversations and in private discussions -- and aides took steps to protect themselves.
"These dynamics began to collide as Trump sat down with people, with him pulling out documents and memos from the WH to make his points," Costa tweeted. "And when people would come by to hear Trump go on and on about his presidency, and often rant about Milley, Trump's aides would also be recording the conversations, in case they ever wanted to contest what was later written. That included when Meadows's ghostwriters stopped by."
Recordings made by two writers working on the former White House chief of staff's memoir captured evidence of Trump discussing top-secret military planning documents to push back on a contemporaneous report on Milley's concern the then-president would issue illegal orders.
"The audio, recorded by a Trump aide, includes remarks Trump made to two ghostwriters for his last chief of staff, Mark Meadows," Costa added. "Sometimes aides & visitors weren't even sure if what Trump was talking about on national security or military matters was true or if docs Trump mentioned existed, sources recalled. But Trump seemed to talk a lot about Milley and his own view of what really happened on that front."