It's tempted to sneer at this very public and nasty fight between two men who used to work together-ish.

WASHINGTON — President Trump excommunicated his onetime chief strategist, Stephen K. Bannon, from his circle on Wednesday, ending for now a partnership of convenience that transformed American politics while raising questions about the future of the nationalist-populist movement they cultivated together.

The rupture came after Mr. Bannon was quoted in a new book disparaging the president’s children, asserting that Donald Trump Jr. had been “treasonous” in meeting with Russians and calling Ivanka Trump “dumb as a brick.” Mr. Trump, described by his spokeswoman as “furious, disgusted,” fired back by saying that Mr. Bannon had “lost his mind.”

In a written statement, the president excoriated Mr. Bannon as a self-promoting exaggerator who had “very little to do with our historic victory” in the 2016 presidential election and was “only in it for himself.” Rather than representing Mr. Trump’s hard-core political base or supporting his agenda to “make America great again,” Mr. Bannon was “simply seeking to burn it all down,” the president said.

It's also tempting to hope that this sort of fight might cause this presidency to implode, and allow us to return to seeing grown-ups in grown-up jobs. (Not at all a fan of the extremely religious Mike Pence, but golly, wouldn't he be better than this? The culture wars are very much last decade. But maybe we can put up with them until the next election?)

But on the human level it's just sad, really.

And also a lesson. That when you rise to the top by being crude and insulting to your opponents (no matter what perfidy your opponents may or may not be guilty of), when you go through your days insulting people, and when you're mostly just looking after Number One, well, don't be surprised when those in your circle turn around to do the same thing once you've let them go, in effect turning your own weapons against you.

Perhaps I'm overly naive, but if instead we chose to rise to the top by being of service to others, by doing what we can to make our neighbours' lives better, or by working every day to share our gifts with others, maybe then we wouldn't find ourselves in pickles like this.