I've been afraid to go too hard after mass-murderer Anders Breivik for citing Islamophobic blogger Pamela Geller because people will respond that Osama bin Laden has cited Jimmy Carter and Walt and Mearsheimer. Steve Walt deals with this question in a great post on Breivik. On the intellectual culpability issue, he says that OBL did what he did without reading Walt and Mearsheimer, while the same cannot likely be said about Breivik/Geller:
As you'd expect, some of [Robert Spencer and Pam Geller's] defenders have pointed out that the late Osama bin Laden also cited some writers favorably, including Noam Chomsky, Michael Scheuer, and yours truly. Bin Laden also mentioned John Perkins (author of Confessions of an Economic Hit Man) and Jimmy Carter's Palestine: Peace Not Apartheid. The defenders suggest that these two situations are identical and accuse those who see a link between Breivik and his Islamophobic inspirations of a double standard.
This line of defense is pretty silly because it completely ignores conventional notions of causality. Osama bin Laden began his terrorist career over a decade before the authors he cited had even started the books to which he subsequently referred. He didn't need to read Chomsky, Perkins, Scheuer, or me in order to develop his violently fundamentalist outlook; it was firmly in place long before I wrote one word and wholly at odds with the central views of the people to whom he referred. Indeed, I doubt he ever read my work; if he had, I wonder what he made of our defense of Israel's right to exist, our condemnation of terrorism in general and al Qaeda in particular, and our explicit denunciations of anti-Semitism?
By contrast, it is clear from Breivik's own statements that his thinking was shaped by the various Islamophobic writers whose work he cites (and whose websites he patronized and posted on). He wasn't dreaming up terrorist plots 20 years ago and then citing these writers after the fact to justify it; on the contrary, these works apparently helped convince him that radical violence was necessary in part because there was a looming danger to "the West." Geller, Spencer, and their ilk are not responsible for his specific decisions and actions, of course, but they do bear some responsibility for creating and promoting a vision of cultural conflict that makes such extreme responses more likely.
I'd say the distinction Walt makes extends to the bizarre ideas that neocons came up with, that George W. Bush then deployed in Iraq. And I'd add this: Breivik might actually be called an intellectual, if a twisted one; his manifesto is very articulate about repulsive ideas. Ideas that Geller and Spencer share. And I bet that if you had shown his arguments about "cultural Marxism" and political correctness and Islam's threat to Geller a couple of weeks ago, she'd have agreed with them wholeheartedly. I wonder what in his manifesto she'd disagree with!