A thought,
As much as a want strong Conservatives, please remember that about 98% of votes are strictly Party Line votes.
To lose an 88% Conservative to someone who is effectively unknown statewide, is to probably hand the seat to the Dems in the 2016 General.
We will never get everything we want, but 88 Birds in Hand are better than 100 in Bush.
Live long and prosper.
I don't know Burr well enough to say if this is his situation, but people in NC might and I am merely suggesting that they don't spend a lot of effort taking him out if he will vote with Trump/Cruz next year. If he will obstruct them, as McConnell will, fine, raise the funds and divert them to the primary instead of using them in another race.