Trump's endorsement still wins primaries, which is bad news for any Republican thinking of crossing him before 2028.

• Louisiana Senator Bill Cassidy lost his primary to Ed Gallrein, a Navy SEAL and fifth-generation farmer almost no one had heard of before Trump backed him.
• Cassidy was one of seven Republicans who voted to impeach Trump over January 6, and Trump never forgave him.
• Kentucky Congressman Thomas Massie has dropped about eight points in a month after Trump turned on him, and he is now trailing.
• Mike Pence quietly launched a book this week and it flopped, getting only a few hundred likes and angry replies calling him a traitor.
• Republicans who attacked Trump in public, like Liz Cheney, Chris Christie, Adam Kinzinger, and John Bolton, have all faded from politics.

Outlook: More Republicans who broke with Trump are likely to lose their seats in upcoming primaries, and 2028 will test whether his endorsement still carries this much weight once he is out of office.