David French of National Review Online explores the role highly volatile rhetoric plays in provoking real violence.

Whenever there is a politically motivated murder, there is an immediate race to find and fix the “real” blame for the attack — to find that rhetoric that allegedly motivated the murder and discredit the speaker. Perhaps the worst modern example is the rush to blame Sarah Palin for Jared Loughner’s attack on Arizona Democratic representative Gabrielle Giffords.

In the absence of any evidence that Loughner was motivated by politics, some on the Left launched one of our tiresome “national conversations” on civility. Others went so far as to blame the Tea Party. …

… The political motivation is obvious. Tie an opponent to dreadful violence, and you can discredit him entirely, banishing him from mainstream discourse. It’s an impulse not confined to the Left. Just this week, the Cleveland Police Association president declared that “President Obama has blood on his hands” despite the fact that he never — not once — stated or implied that violence against the police was justifiable or acceptable.

But what about the explicit calls for violence that do exist? We’ve seen Black Lives Matter protests degenerate into violence, with protesters cheering loudly when police are hurt. We’ve seen marchers chant, “What do we want? Dead cops!” or “Pigs in a blanket, fry ’em like bacon.” Twitter has been a cesspool of violent anti-cop sentiment, with some apparent Black Lives Matter supporters openly celebrating the murders in Dallas and Baton Rouge.

Two things can be true at once. First, it is true that ultimate responsibility for violent acts rests with the criminal and his or her co-conspirators. A person does not lose his moral agency merely because his peer group is evil or because he is influenced by calls for violence.

Second, it is also true that calls for violence — especially when those calls come from one’s peer group — can be persuasive. One of the most obvious truths in human history is that words matter. Words can motivate revolutions, and they can certainly motivate murder. While I’ve got my disagreements with such clichés as “The pen is mightier than the sword,” no one doubts that the pen is mighty — and that’s precisely why our nation’s founding generation strove to protect free speech.