The unlikely alliance of former White House chief strategist Stephen Bannon and President Trump seems to be at an end, undone by Bannon's remarkably loose lips. The quotes revealed in the new book Fire and Fury: Inside the Trump White House by Michael Wolff don't really reveal much that's new (Trump and his family are idiots? Well knock me over with a feather), but the president found them insulting enough to cast Bannon out. Despite Bannon's apologies, the rumpled would-be Svengali has even lost the support of billionaire financier Robert Mercer and his daughter Rebekah, his chief patrons in recent years, suggesting his influence over Republican politics could burn down to nearly nothing.

The story of Bannon and Trump's relationship isn't just about a couple of colorful characters; it also tells us something important about this presidency and the Republican Party. Even if Wolff's book had never come out, Bannonism was already dead. In the era of Trump, it never had a chance.

While it sometimes appears that Bannon wants nothing more than to destroy all he surveys, including his own party, he always had an agenda, an extraordinarily ambitious one at that. He believes that there's already a war going on between the white, Christian West and the Islamic world, a grand clash of civilizations that will determine humanity's fate. "There is a major war brewing, a war that's already global," he said in 2014. "Every day that we refuse to look at this as what it is — and the scale of it, and really the viciousness of it — will be a day where you will rue that we didn't act."

The first policy shifts that grew out of Bannon's ideas, like efforts to clamp down on both legal and illegal immigration, were certainly amenable to President Trump. But as Trump now understands, he never had Bannon's loyalty. Bannon saw Trump only as a vehicle for his own agenda, one Trump was never going to fully appreciate in all its ambitious majesty, even if the candidate might share pieces of it. What Trump certainly shared was its destructive force, the idea that smashing existing norms and institutions was essential to doing what Bannon wanted.

And Bannon certainly had something to offer Trump. His dark genius, such as it was, lay in identifying groups of angry people who could be mobilized for a political end, whether they really understood what that end was or not. As Joshua Green, author of the book Devil's Bargain: Steve Bannon, Donald Trump, and the Storming of the Presidency, explains, even before Bannon took over Breitbart News and later became CEO of the Trump campaign, a brief experience in the video game industry "awakened him to the power of what he called 'rootless white males' who spend all their time online. And five years later when Bannon wound up at Breitbart, he resolved to try and attract those people over to Breitbart because he thought they could be radicalized in a kind of populist, nationalist way."

They were, but even after Bannon helped guide Trump to victory, he may have overestimated the degree to which Trump voters were actually in the market for a clash of civilizations.

If there's anything the innumerable "In Trump Country, Trump Supporters Continue to Support Trump" articles have taught us, it's that the support of Trump's base is overwhelmingly personal. They'll follow their leader through as many substantive flip-flops and betrayals as Trump can serve up, whether it's stocking his administration with Wall Streeters when he said he'd stick it to the elites, trying to cut Medicaid when he said he'd protect it, or never getting around to building that wall and making Mexico pay for it. What they love is Trump himself, not what he does.

Bannon helped create that cult of personality, and now it can't be undone. The Republican Party is essentially divided between one group that wants the traditional GOP agenda — tax cuts, less regulation on corporations, abortion restrictions — and another group that wants whatever will serve the greater aggrandizement of Donald Trump. There is no genuine populist Bannonite force in the middle. As for the enemies abroad that Bannon would like to fight, the truth is that as much damage as Trump may do in foreign affairs, the rest of the world regards him as sui generis — yes, they think he's a lunatic halfwit, but don't be surprised when the next American president resets our relations with the globe to the pre-Trump status quo that Bannon found so unacceptable.

All that isn't to say that Bannon and Trump don't still share many ideas about things like immigration, or that many of those ideas won't be expressed in policy. But when you help get Trump elected, it's always going to be first and last about Trump himself. He will be with you as long as your agenda serves him, but he's never going to serve any agenda. The reason Bannon fell out of favor in the first place and had to leave the White House was that he stole some of Trump's limelight, a sin even more unforgivable than insulting Trump's family.

Bannon can certainly be glad he got as far as he did. If he had learned to manage Trump's ego better — and kept his big mouth shut — who knows what he might have accomplished.