"I can understand fully how Steve Bannon feels," Trump said in October.
Then Bannon placed a bad bet on Roy Moore in the Senate race in Alabama, denting the perception that he could influence or even read a red-state electorate.
His critical comments about Trump's adult children, published in Michael Wolff's "Fire and Fury" last week, enraged the president, who declared that Bannon had "lost his mind."
White House press secretary Sarah Huckabee Sanders said last Thursday that Breitbart should "look at and consider" cutting ties with Bannon. Five days later, Bannon was out.
"Steve is a valued part of our legacy," Breitbart chief executive Larry Solov said, "and we will always be grateful for his contributions and what he has helped us to accomplish."
Bannon said he was "proud of what the Breitbart team has accomplished in so short a period of time in building out a world-class news platform."
What's next for Bannon?
"I don't think he'll be quiet or silent for very long," Kurt Bardella, a former Breitbart spokesman, told me. "Accepting fate or defeat is not in his DNA. Someone who entertains running for president doesn't just retreat and shrink away into anonymity. He will try and reinvent himself. He will try and finish what he started."
Bardella's remark about presidential ambitions refers to a December Vanity Fair article in which Gabriel Sherman reported that a White House run "has at least been a passing thought" for Bannon.
"In October," Sherman wrote, "Bannon called an adviser and said he would consider running for president if Trump doesn't run for re-election in 2020. Which Bannon has told people is a realistic possibility.
In private conversations since leaving the White House, Bannon said Trump only has a 30 percent chance of serving out his term, whether he's impeached or removed by the Cabinet invoking the 25th amendment."
Another possible avenue for Bannon already is closed. Wolff reported in his book that former Fox News chairman Roger Ailes approached Bannon in April about teaming up to launch a new conservative television network that would feature the just-fired Bill O'Reilly.
According to Wolff, Bannon said at the time that he wanted to stay in the White House.
Bannon left the White House just four months later, but by then Ailes had died.
Bannon could attempt to start a new venture without Ailes or perhaps go back to making documentaries, like the one he produced in 2011 about Sarah Palin, before taking the helm at Breitbart.
But those projects might require fundraising and Bannon, through his falling-out with Trump, has alienated the billionaire Mercer clan, which would have been his most natural source of financial support.