The split between President Trump and former chief strategist Stephen K. Bannon over the U.S. Senate race in Alabama should be easy enough to explain. Even friends with similar views disagree sometimes, right?

That is not Bannon's explanation, however. Appearing on Sean Hannity's Fox News show Monday night, the Breitbart News chairman suggested that he understands Trumpism better than Trump himself — that he is supporting Republican challenger Roy Moore instead of the president's candidate, incumbent Sen. Luther Strange, because Moore is actually the ally Trump needs, whether he realizes it or not.

“What I'm here to do is to support Donald J. Trump by having folks down here support Judge Roy Moore,” Bannon told Hannity after speaking at a rally for Moore in Fairhope, Ala., on the eve of a GOP primary runoff. “I think Roy Moore is the guy that's going to represent Donald Trump and fight the establishment.”

“We're not here to defy President Trump,” Bannon added a moment later. “We were here to praise and honor him. And we think the best way to do that is to send somebody to Washington, D.C., out of Alabama — the good folks of Alabama to send somebody that's going to have Donald Trump's back.”

Bannon made those remarks three days after Trump spoke at a rally for Strange. Trump's position is that Strange is the guy who will have his back. Yet here is Bannon, claiming that Trump doesn't know what is best for himself.

Bannon knows best, according to Bannon.

Here's the truly zany thing: Trump seems to think that Bannon might be right.

“I'll be honest: I might have made a mistake,” Trump said at Strange's rally on Friday, in one of those off-script moments that characterize his stump speeches.

“And I told Luther,” Trump continued, “I have to say this: If his opponent wins, I'm going to be here campaigning like hell for him.”

Bannon is hardly alone among Trump supporters in backing Moore, and the president appears to be considering the possibility that his base really did do a better job of picking the most Trump-like candidate than he did. My Fix colleague, Amber Phillips, framed the runoff like this:

An establishment candidate is running for his political life against a controversial, say-anything figure whom the elites despise. And against all political logic, the establishment may very well lose.

It's as if the 2016 presidential campaign is playing out in the Alabama Senate Republican primary to replace Attorney General Jeff Sessions. Only this time, President Trump is on the establishment side, and Alabama voters could very well go against the president they adore.

The troubling development, for Trump, is that some of his backers are willing to divorce Trumpism from Trump himself. They cling more tightly to what he symbolized during his insurgent campaign for the White House than they cling to him — to the point of ignoring his endorsement.

Earlier this month, Ann Coulter, who wrote a book called “In Trump We Trust,” was asked in an interview on WBAL radio in Baltimore whether she still trusts in Trump.

“Um, I trust in Trumpism,” Coulter replied.

Coulter supports Moore and told Breitbart that the president's decision to line up behind Strange was “completely idiotic.”

Trump is now in a fight with Bannon and company to define his own political brand. Trump says Strange fits the brand, Bannon says otherwise, and Trump has already hedged that Bannon might be right.