For a long time, people have predicted the crackup of American conservatism, the end of a Republican Party dominated by the conservative movement as one of the major powers in our politics. Demographic trends were supposed to permanently marginalize the right. Barack Obama’s 2008 victory was supposed to signal conservatism’s eclipse. The rise of Donald Trump was supposed to shatter Republican politics the way that slavery once broke the Whigs.

Conservatism survived all these prophecies, always clawing back to claim a share of power, maintaining unity and loyalty by offering a bulwark against liberal ambition even as its own agenda became more and more threadbare.

So it would be a foolhardy prophet indeed who looked at the Jan. 6 riot at the Capitol and assumed that this time, under this pressure, the conservative coalition will finally break apart, sending the Republican Party deep into the wilderness and reshaping American ideological debates along new lines.

But breaking points do come, and the violent endgame of the Trump presidency has exposed a new divide in the conservative coalition — not a normal ideological division or an argument about strategy or tactics, but a split between reality and fantasy that may be uniquely hard for either self-interest or statesmanship to bridge.

At the same time, it has cast the key weakness of conservatism into even sharper relief: the growing distance between right-wing politics and almost every nonpolitical power center in America, from the media and culture industries to the old-line corporate suites to the communications empires of Silicon Valley.

The Republican Party has succeeded in the past decade, despite its decadence and growing provincialism, by providing a harbor for voters who want to cast a vote, for all kinds of different reasons, against consolidated liberal power. And it has found new support in unexpected places: first the Obama-Trump voters of the Midwest in 2016, then the immigrant neighborhoods that trended rightward in 2020.

But the implicit bargain of the Trump era required traditional Republicans — from upper-middle-class suburbanites to the elites of the Federalist Society — to live with a lot of craziness from their leader, and a lot of even crazier ideas from the very-online portions of his base, in return for denying Democrats the White House. And it’s not clear that this bargain can survive the irruption of all that crazy into the halls of the Capitol, and the QAnon-ification of the right that made the riot possible.

Even before Jan. 6, the difficulty of balancing normal Republican politics with an insistence that Mike Pence could magically overturn a clear election outcome helped cost the party two Senate seats in Georgia. Even before the riot, finding post-Trump leaders who could bridge the internal divide, bringing along his base but also broadening the party, was going to be an extraordinary challenge.

But the Republican Party that lost Georgia a week ago still looked competitive enough to count on holding, say, 47 Senate seats even in a tough election cycle. A week later, it seems the party could easily break harder, and fall further.

Here’s how it could happen. First, the party’s non-Trumpist faction — embodied by senators like Mitt Romney and Lisa Murkowski, various purple- and blue-state governors and most of the remaining Acela corridor conservatives, from lawyers and judges to lobbyists and staffers — pushes for a full repudiation of Trump and all his works, extending beyond impeachment to encompass support for social-media bans, F.B.I. surveillance of the MAGA universe and more.

At the same time, precisely those measures further radicalize portions of the party’s base, offering apparent proof that Trump was right — that the system isn’t merely consolidating against but actively persecuting them. With this sense of persecution in the background and the Trump family posturing as party leaders, the voter-fraud mythology becomes a litmus test in many congressional elections, and baroque conspiracy theories pervade primary campaigns.

In this scenario, what remains of the center-right suburban vote and the G.O.P. establishment becomes at least as NeverTrump as Romney, if not the Lincoln Project; meanwhile, the core of Trump’s support becomes as paranoid as Q devotees. Maybe this leads to more empty acts of violence, further radicalizing the center right against the right, or maybe it just leads to Republican primaries producing a lot more candidates like Marjorie Taylor Greene of Georgia, to the point where a big chunk of the House G.O.P. occupies not just a different tactical reality from the party’s elite but a completely different universe.

Either way, under these conditions that party could really collapse or really break. The collapse would happen if Trumpists with a dolchstoss narrative and a strong Q vibe start winning nominations for Senate seats and governorships in states that right now only lean Republican. A party made insane and radioactive by conspiracy theories could keep on winning deep-red districts, but if its corporate support bailed, its remaining technocrats jumped ship and suburban professionals regarded it as the party of insurrection, it could easily become a consistent loser in 30 states or more.

Alternatively, a party dominated by the Trump family at the grassroots level, with Greene-like figures as its foot soldiers, could become genuinely untenable as a home for centrist and non-Trumpist politicians. So after the renomination of Trump himself or the nomination of Don Jr. in 2024, a cluster of figures (senators like Romney and Susan Collins, blue-state governors like Maryland’s Larry Hogan) might simply jump ship to form an independent mini-party, leaving the G.O.P. as a 35 percent proposition, a heartland rump.

None of this is a prediction. In American politics, reversion to the gridlocked mean has been a safe bet for many years — in which case you’d expect the MAGA extremes to return to their fantasy world, the threat of violence to ebb, Trump to fade without his Twitter feed and the combination of Biden-administration liberalism and Big Tech overreach to bring the right’s blocking coalition back together in time for 2022.

But if Biden governs carefully, if Trump doesn’t go quietly, if MAGA fantasies become right-wing orthodoxies, then the stresses on the Republican Party and conservatism could become too great to bear.

I woke up last Wednesday thinking that the G.O.P. had survived the Trump era, its power reduced but relatively stable, with some faint chance to redeem itself — by carefully shepherding it supporters back toward reality, while integrating elements of populism into the reality-based conservatism that our misgoverned country needs.

A week later, that hope seems like as much of a fantasy as QAnon. Instead, it feels as if the Republican Party survived Trump’s presidency, but maybe not his disastrous and deadly leaving of it.

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