There's a lot of debate about whether the Tucson shooter Jared Loughner was inspired by right-wing rhetoric or was just nuts. Why not both? Conservatism is driven by insanity, so obviously Jared was both. Not to say all mentally insane people will go out and shoot people of course. Conservatives have a worldview that leans away from reality to the point where I can classify them as insane.
To put it in a different way: not all crazy people are conservative, but all conservatives are crazy.