Danielle Crittenden, the wife of conservative David Frum, sees a serious narrowing of the intellectual range of opinion that you can safely express within contemporary American conservatism (and still remain in the fold):
We have both been part of the conservative movement for, as mentioned, the better part of half of our lives. And I can categorically state I’ve never seen such a hostile environment towards free thought and debate — once the hallmarks of Reaganism, the politics with which we grew up — prevail in our movement as it does today. The thuggish demagoguery of the Limbaughs and Becks is a trait we once derided in the old socialist Left. Well boys, take a look in the mirror. It is us now.
The reason that nuanced conservatives like Danielle Crittenden and David Frum are finding little intellectual wiggle room within the American conservative movement is, in my view, a straightforward one: the movement has obviously been taken over by anti-intellectual authoritarians and fundamentalists. It is now a nostalgia based and populist cult. How could any ironic and reasonable person feel comfortable within it?
Prometheus Unbound 