On Tuesday night, Ken Paxton, the scandal-plagued attorney-general of Texas and an uncompromising avatar of the MAGA movement, bulldozed past Senator John Cornyn to clinch the Republican nomination for a US Senate seat—a result that, viewed from Washington, signals the final triumph of fealty to Donald Trump over every other political virtue. Paxton, who secured a last-minute presidential endorsement, won with more than 62 per cent of the vote, capping the most expensive Senate primary campaign in American history. “Today change was on the ballot, and change won,” he declared, thanking Trump for refusing to abandon him.

Paxton’s rout was the centrepiece of a night of primary victories for the president’s handpicked candidates. State senator Mayes Middleton defeated Representative Chip Roy for the attorney-general nomination, and Alex Mealer, a combat veteran backed by Trump, triumphed in a Houston-area congressional runoff. These outcomes, combined with Cornyn’s demise, illustrate how Republican voters have redefined loyalty: the four-term incumbent had voted with Trump more than 99 per cent of the time, yet that proved insufficient. Viewed from European capitals, the purge of a senior legislator such as Cornyn, who once led the party’s Senate campaign arm, confirms that any deviation from Trump’s personal demands—however minor—is now politically fatal inside the GOP.

The general election will test whether a party that prizes ideological purity can hold Texas, a state it has dominated for decades. Democrats have not won a statewide race here since 1994, but James Talarico, a Presbyterian pastor and state legislator, is running competitively in early polling. The Cook Political Report immediately downgraded the contest from “likely Republican” to “lean Republican,” and Republican strategists privately estimate it could cost a quarter of a billion dollars to defend the seat—money urgently needed elsewhere. Viewed from Mexico City, a Democrat representing Texas might soften the bellicose border rhetoric that has characterised the Trump era, while analysts in London note that any genuine Texan opening would dramatically reconfigure the arithmetic of a Senate the Republicans control by just 53 seats.

Yet the longer-term cost may be strategic. By purging an experienced legislator such as Cornyn, Trump has gambled that base mobilisation can overcome a candidate whose own party once impeached him for corruption. The calculation risks giving Democrats a foothold in the Sun Belt at a moment when the president’s grip on Capitol Hill is already frayed by overseas wars and domestic priorities. Whether that wager succeeds or hands the Democrats the Senate for the final two years of Trump’s term, the Texas result already confirms that, in today’s Republican Party, absolute fealty is the only currency that trades.