Voices in the Chorus

No one wants to deny that the murderer or Dr. George Tiller bears responsibility for his actions, but the fact is that this crime would not have happened without the groundwork having been laid by a number of people with big megaphones. While no one speech act on the part of Bill O'Reilly, Randall Terry, or anyone else can be causally linked to the horrible crime, certainly the sum total of them were a causal factor in creating the environment which did play a causal role. Having the big megaphone means having more impact on people, what moral responsibility comes with it? Inciting violence is clearly problematic, but what about what the speaker thinks is a merely rhetorical call for violence? What of charged rhetoric that does not directly call for violence, but is intended to get people riled up to a point where some could commit violence? Are the speakers responsible for acts they did not commit, but were a part of establishing the environment from which the acts spring?