Post opinion writer Jonathan Capehart says President Trump's white nationalist tirade came from fertile ground expertly tilled by Steve Bannon. That won't stop now that Bannon is out. (Gillian Brockell/The Washington Post)

Stephen K. Bannon, President Trump’s chief strategist, is out: ““White House Chief of Staff John F. Kelly and Steve Bannon have mutually agreed today would be Steve’s last day,” according to a White House statement.  Since his interview with the American Prospect trashing his colleagues and undercutting Trump’s North Korea policy, it seemed only a matter of time before he was ousted. The White House will spin this as somehow presidential and responsive to calls for “radical changes,” as Sen. Bob Corker (R-Tenn.) put it, maybe even as a way to stave off staff resignations. You should not fall for it.

Maybe Bannon appealed to Trump’s worst instincts, but honestly, does the president have any good ones? It is said that Bannon’s pro-Russian views made for constant tension with hawkish advisers, but does anyone think Trump is not compromised in some fashion when it comes to Russian President Vladimir Putin? Bannon was the faux intellectual giving direction and form to Trump’s views, but Trump’s deeply warped views, glaring ignorance and defective character are the root of the problem. Trump will still talk to allies harboring the same worldview, will still tweet impulsively, will still repeat discredited hoaxes and will still be unfit for the presidency. And most ominously, the Russia investigation will still grind on, and Trump will no doubt lash out at both the special prosecutor and the media. This personnel move may buy him a brief pause in the chaos, but his presidency is living on borrowed time.

How will we know that Bannon’s departure is more than another staff shuffle? Look to see if Trump continues to campaign against Republican incumbents, obsess over news coverage, treat Russia with kid gloves, saber-rattle over North Korea and stoke racial tension.

We find any change of that magnitude highly unlikely. Trump knows very little else and never will imagine his base will defect.

What we don’t know is what would be left if Trump excised the ghost of Bannon and shunned the white nationalists. He’s never had a coherent worldview or domestic agenda. He can, one supposes, go hard right, cozying up to the right wing and trying to be a conventional right-winger. But then that agenda has shown to be wholly unpopular. He could alternatively adopt a strict economic populism, but that will perpetuate a war with the party’s business base.

Indeed, Trump may be in worse shape than ever. Bannon may lead his true believers away from Trump while the rest of the party turns its back on him. Trump could very well find himself utterly isolated, lacking a real agenda or any defense against a vengeful Bannon and determined prosecutor.

Robert Kuttner, co-editor of the American Prospect, got an unexpected interview with White House chief strategist Stephen K. Bannon on Aug. 15. (Peter Stevenson/The Washington Post)