As I periodically comment, the contemporary Republican Party and conservative movement really needs to draw firmer lines between acceptable discourse and dangerous lunacy. An example I frequently cite is Alex Jones, the Texas-based radio host and purveyor of InfoWars.com and the Prison Planet forum. He also produces documentaries of his wild conspiracy theories -- he is, for instance, a prominent 9/11 "Truther," who believes the US government ordered the attacks. And that's just one of his nutty ideas.
Jones should be treated as an untouchable pariah. My rule of thumb: anyone who goes on his show as a guest once, I'd give the benefit of the doubt and assume they're just an idiot; anyone who goes on more than once, I'd say is knowingly supporting hateful, dangerous propaganda; anyone who goes on regularly, I'd say that anyone who treats them as a respectable political entity is guilty of blurring the line between legitimate discourse and dangerous lunacy. (And yes, that goes for the rare Democrat who goes on the show as well.)
In a couple of days, we will apparently see a Republican Presidential debate, hosted by the South Carolina GOP, in which 50% of the candidates appearing are regular guests on the Alex Jones Show. Congressman Ron Paul is on monthly. (His son, Senator Rand Paul, also appears periodically.) former New Mexico Governor Johnson has been on several times since early 2010, most recently two weeks ago. The only other confirmed debate participants are Tim Pawlenty and Herman Cain, neither of whom have crossed that line, as far as I know.
[Update: It's also true that two 2008 Democratic candidates went on Jones's show, Dennis Kucinich and Mike Gravel. Shame on both of them -- I know I knocked Kucinich for it at the time. I believe Kucinich only went on once. Gravel, of course, rarely if ever got onto the stage for a debate with major candidates.]
Republicans don't call Paul and Johnson out on this kind of crap, presumably because A) nobody's worried that they're going to actually win the nomination, and B) criticizing them risks alienating a sizable chunk of conservative-libertarians who Paul and Johnson help bring to the party.
To my mind, it's absolutely unacceptable, and they should be called out on it.