From today's column:

Today, as in the early years of the Clinton administration but to an even greater extent, right-wing extremism is being systematically fed by the conservative media and political establishment.

And that's what's so troubling and important to understand about the current hate speech phenomena that's greeted the Obama administration. As I've noted, the kind of vigilante, militia-style rhetoric that we're seeing and hearing today was also hatched in response to the election of Clinton in the early `90's. But haters back then had to search out the really vile stuff from the underground media, or a handful of AM talk show hosts.

Today, thanks to Fox News, Limbaugh and right-wing bloggers, that same kind of dehumanizing, anti-Democratic rhetoric has been dumped right into the mainstream. It's part of our everyday conversation and fringe players now see their deepest fears legitimized by so-called mainstream outlets.

Notes Krugman:

And at this point, whatever dividing line there was between mainstream conservatism and the black-helicopter crowd seems to have been virtually erased.