It comes just as Mr. Trump is frantically seeking to stabilize a presidency besieged by internal chaos and to cope with his own Justice Department's investigation into his campaign's possible collusion with Russian agents meddling in the 2016 election.
The president already has his hands full trying to discredit that probe and by association Special Counsel Robert Mueller, even as Mr. Trump insists he has no intention of firing him. He also has now he has turned against Mr. Bannon, his onetime guru.
The catalyst for this bizarre bombshell is a recently released insider book on Mr. Trump and his administration by free-lance writer Michael Wolff. In it, Mr. Bannon is said to have described Donald Trump Jr.'s meeting with Russian officials at Trump Tower in 2016 as "treasonous" and "unpatriotic" — among other explosive contentions.
In reply to derogatory remarks Mr. Bannon made about Trump family members, the president contended that Mr. Bannon's role in his campaign and first months of his administration were overblown. Of his old close adviser he tweeted, "When he was fired, he not only lost his job, he has lost his mind." Mr. Bannon, he said, had "very little to do with our historic victory." Mr. Trump also instructed his lawyers to send Messrs. Bannon and Wolff cease-and-desist letters, citing an alleged breach of a nondisclosure agreement Mr. Bannon has supposedly signed.
It's clear now that Mr. Bannon has become another cross for the president to bear among an accumulating list of critics in and out of his Republican Party. After being fired by Mr. Trump, Mr. Bannon returned to his old job running the alt-right Breitbart News website, which formerly was a conspicuous cheerleader for the president. He stepped down from the company Tuesday, under pressure. Under Mr. Bannon, Breitbart had become a vehicle for his own political ambitions, including clashes with the Republican Party establishment and national committee, which he appeared to be targeting for a takeover.
Beyond revealing the breakup itself, Mr. Wolff's book provides a stinging insight into what some White House insiders thought of the president. One fired campaign aide, Sam Nunberg, is quoted as saying he was assigned to tutor Mr. Trump on the Constitution. "I got as far as the Fourth Amendment," he said, "before ... his eyes are rolling back in his head." Mr. Bannon himself is said to have commented that Mr. Trump's daughter Ivanka was "dumb as a brick."
Also, a former deputy chief of staff, Katie Walsh, is quoted as saying that trying to deal with the president was "like trying to figure out what a child wants" — an observation she later denied having made.
Mr. Wolff also reports Ms. Walsh says she was obliged to respond to three different Trump power centers: Reince Priebus, the first chief of staff; Mr. Bannon and Trump son-in-law Jared Kushner.
"For Walsh," Mr. Wolff writes, "it was a daily process of managing an impossible task: almost as soon as she received direction from one of the three men, she would be countermanded by one of another of them."
It was no wonder the Trump White House came off from the outside as a confused madhouse, with a president constantly getting mixed messages and making decisions as an ill-informed neophyte would-be politician.
Whether all the disclosures Mr. Wolff has reported are accurate or not, taken together they constitute more tasty morsels for both the conventional news media and the social media platforms Mr. Trump himself so favors.
As a new year gets started, there are already more than enough reasons to worry about the state of the union in the era of Donald J. Trump and his merry band of confusion-spinners.
Jules Witcover is a syndicated columnist and former long-time writer for The Baltimore Sun. His latest book is "The American Vice Presidency: From Irrelevance to Power" (Smithsonian Books). His email is email@example.com.