Primary challenges traditionally hurt incumbent Presidents.
He’s hasn’t lost his mind, he’s trying to soften Trump up for Com-Allah Harris, pure and simple. But unlike the most recent primary challengers (Buchanan, to Bush’s right) (Kennedy to Carter’s left) he’s attacking from the direction opposite to the party’s base so the effect won’t be the same.
Slick Willie Weld will inflict as much damage to Trump as a gnat on the windshield of a Buick going at 120 mph. He is an epic left-wing loser and lush who destroys anything and everything he is ever put in charge of. Some poor dopes at a college in Kentucky thought he’d be great at running it, and instead he put them out of business in record time.