I know we love to say "let them fight", but we've seen this before, and it didn't work out - for us.
When the Tea Party formed, the idea was that the crazy Tea Party candidates would primary the establishment Republicans, and if the crazy ones won, they'd be unable to win in the general. For some of them, that was true.
But the party as a whole adopted that crazy, and it didn't put a dent in their viability, in states or nationally. It even seemed to help. That's how we ended up with Trump.
The same thing is going to happen now, but worse. It's crystal clear that the crazies are going to win this fight, and they are way crazier than the Tea Partiers were. So now we just have to hope that, this time, they really are crazy enough that it hurts their viability? Fuck.