“Thomas Massie caught in a throuple!” screamed the AI-generated attack ad that showed the Republican congressman supposedly dining with Alexandria Ocasio-Cortez and Ilhan Omar then checking into a hotel with the two progressives. “Thomas Massie betrayed President Trump!” it added.

Crude but effective, as it turns out. Massie, from northern Kentucky, lost the most expensive House of Representatives primary election in history on Tuesday to Ed Gallrein, a farmer and former US Navy Seal backed by Donald Trump.

Massie’s ousting after nearly 14 years was proof that Trump still rules the Republican party like a mob boss who can get a horse’s head placed in any bed. Steven Cheung, the White House communications director, posted on X: “Do not ever doubt President Trump and his political power. Fuck around, find out.”

But the president’s allies are in danger of scraping false hope from Kentucky’s fourth congressional district. Trump commands fierce loyalty from a base that is shrinking. He is like a cult leader whose commune keeps getting smaller while the devotion inside grows more intense.

For sure, Trump’s political death has been greatly exaggerated. He was written off after the January 6 insurrection, but in the end it was Liz Cheney, his leading Republican critic on that effort to subvert democracy, who paid the price when she lost her House seat in Wyoming in 2022.

Similarly, it became a received wisdom that the Jeffrey Epstein files would be Trump’s undoing, that here, finally, was the moment his base would revolt against him. Yet Massie was the lead Republican on that cause, working with Democrat Ro Khanna to force the release of the files, only to suffer the same fate as Cheney.

Chris Murphy, a Democratic senator, posted on X: “So there you have it. If you lead a campaign against powerful pedophiles, you get drummed out of the Republican Party.” Marjorie Taylor Greene, a former Republican congresswoman now feuding with Trump, wrote: “Releasing the Epstein files was our demise. But it was worth every single bit because now everyone knows the truth.”

And in recent weeks, even as negative headlines swirled, Trump has quietly been notching up some political victories. The supreme court gutted a major section of the Voting Rights Act, giving Republicans the power to redraw congressional district maps to weaken the influence of Black and other minority voters. It also rejected an emergency request by Democratic officials in Virginia to use a newly approved district map in the midterm elections.

The president’s revenge tour has been no less successful. He secured the downfall of several Indiana state senators who defied him on redistricting, and of Louisiana senator Bill Cassidy, who had voted in favour of Trump’s conviction at his January 6 impeachment trial.

Then there was Massie who, on paper at least, seemed like a tougher nut to crack. Interviews by the Guardian with political insiders in Kentucky last month found plenty of confidence that Massie could prevail. They pointed to the advantages of incumbency, and respect he had gained as a principled maverick in a state with a mile-wide libertarian streak that helped birth the Tea Party and elects wild cards such as Senator Rand Paul.

But Trump got to work. He branded Massie a “moron”, a “nut job” and a “major sleazebag” and rallied against him. He dispatched two of his most trusted strategists – Chris LaCivita and Tony Fabrizio – to lead a political action committee in support of Gallrein. Even defence secretary Pete Hegseth joined the campaign trail.

In addition Massie, a critic of the Iran war who voted against US aid to Israel, faced accusations of antisemitism, and pro-Israel interest groups spent millions of dollars against him. In his concession speech on Tuesday, he quipped: “I would have come out sooner but I had to call my opponent to concede and it took a while to find him in Tel Aviv.”

The president enjoyed more wins elsewhere on Tuesday. Republicans in Kentucky chose Andy Barr, who was endorsed by Trump, as their Senate nominee to replace longtime Senate leader Mitch McConnell. Other Trump-backed candidates generally performed well, or advanced.

The outcomes are testament to his political resilience, at least within the Republican party, where his approval rating remains at 82%, according to a New York Times newspaper/ Siena poll released on Monday.

But the same poll showed Trump’s overall approval rating down to 37%, the lowest of either term. Nearly two in three voters disapprove both of his handling of the economy and decision to wage war on Iran. Democrats lead Republicans 50%-39% on the generic congressional ballot.

This suggests the Republican party is ever more out of whack with the country at large. Chris Hayes, a political commentator and host on the MS Now network, told viewers on Tuesday: “As the coalition collapses at large, the intensity of who’s left only grows, which means Trump’s control of that faction – increasingly a rump faction in American politics – is expanding, at the same time that his grip on the country is withering.

“Which means this faction of Americans – the 37%, the 35%, who knows how low it will go – are effectively kind of holding the rest of the country hostage. The majority is being pillaged by the minority.”

Elizabeth Warren, a Democratic senator for Massachusetts, told Hayes: “It’s a tighter and tighter hold on a smaller and smaller group.”

The next test of Trump’s strength over his party comes in Texas, where he just endorsed Ken Paxton, the state attorney general, over incumbent John Cornyn for an upcoming Senate primary. He will probably triumph again – but there is widespread consensus that Paxton, an extremist with huge personal and political baggage, is more vulnerable to defeat by Democrat James Talarico.

Forget the Thucydides Trap. This is the Trump Trap: a self-tightening knot in which Republicans must depend on him to win primaries, only to be doomed by him in general elections. Tuesday night proved he rules supreme in Maga-land. But that is only minority rule in America.