Putting all the establishment money into Jeb Bush's campaign
Wouldn't be so much of a problem except that the Establishment's conception of what the GOP should be is basically the British Conservatives - across-the-board austerity, tax cuts for the super-rich and deregulation of banking and finance, while largely ignoring social/cultural issues or immigration. Jeb! was a fine candidate for that, but that agenda falls flat among actual GOP voters.
Jeb had the Bush name , and was terrible campaigner