From a reader:

Jonah, I don’t know if I agree with your point about Marx; political writers, even those whose writings urge a resort to arms, should not be held responsible for what progeny does with their beliefs. That doesn’t make them or their writings less odious, though.
The more peripheral ones, like Rousseau, I have an even harder time believing. If writers should be held responsible for what follows from their works, wouldn’t one have to condemn the writings of the New Testament (the Gospels, of course, not written by Christ himself, but presumably what he said) for the Thirty Years’ War? Would one blame Thomas Jefferson and the Continental Congress for the Civil War, since the belligerents on both sides used the language of the Declaration of Independence for their own justification?
The line, of course, is fuzzy, but what one does with another’s opinions–especially when those opinions do not explicitly call for action–shouldn’t be a liability for the writer. It seems to remove the burden of responsibility from the independent actors who are doing the misdeeds.
Loyal reader,
Josh
P.S. Isn’t it also another way of saying that people like John Yoo should be held liable for the opinions they rendered for EIT policies? I would think not.

Me: I think we’re getting confused about something and it’s probably my fault. I don’t think Rousseau is guilty of murder if someone murders in his name. When I think of guilt-by-endorsement I don’t have that sort of thing in mind at all (though I think we can all agree that direct incitements to violence are a different thing). I’m merely saying that an author’s admirers and acolytes says something about the author, for good or ill. The impact of a book says something about the book and its author. I’m speaking here of how we judge the author as an author, not whether he should be judged as a criminal co-conspirator or some such.