The problem is he's convinced his idiots that anything that attacks him is their enemy, too.
Modern Republicans for the last half century only care about their ends: control, and since everyone who isn't then is bad to them, any means to get control are justified. They start from considering their in-group the only good guys to validate anything and everything they do.
Nail his ass to the wall, but don't expect him to lose votes over it, you've met his voters.