John Cornyn is a pretty good senator, but to many conservatives, Cornyn represents a Republican establishment that disdains the Tea Party and cares little for principle. That’s because Cornyn, as chairman of the National Republican Senatorial Committee, decided to get involved in the Florida Senate primary last cycle, backing liberal Gov. Charlie Crist over conservative Marco Rubio.

It was extraordinary for the NRSC to get involved in a primary, especially siding against an electable conservative. It set off 18 months of Tea Party-vs-Establishment battles.