Nobel Prize-winning economist and liberal New York Times op-ed columnist Paul Krugman is a pretty smart guy, but in a column in yesterday’s Times, is Krugman blaming Bill O’Reilly and Glen Beck for the recent death of a doctor who performed late-term abortion and the attack on the Holocaust Museum?

The basis of the piece goes back to a Homeland Security report a couple of months ago that postulated that the current environment was ripe for possible right-wing domestic terror attacks. The report was criticized and basically forgotten.

Until Krugman brought it back yesterday.

Here’s a sample:

Now, for the most part, the likes of Fox News and the R.N.C. haven’t directly incited violence, despite Bill O’Reilly’s declarations that “some” called Dr. Tiller “Tiller the Baby Killer,” that he had “blood on his hands,” and that he was a “guy operating a death mill.” But they have gone out of their way to provide a platform for conspiracy theories and apocalyptic rhetoric, just as they did the last time a Democrat held the White House.

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

Exhibit A for the mainstreaming of right-wing extremism is Fox News’s new star, Glenn Beck. Here we have a network where, like it or not, millions of Americans get their news — and it gives daily airtime to a commentator who, among other things, warned viewers that the Federal Emergency Management Agency might be building concentration camps as part of the Obama administration’s “totalitarian” agenda (although he eventually conceded that nothing of the kind was happening).