I wonder how many times Kathy Boudin said and heard the word "pig" before she and her rebel cohorts offed a pair of them in 1981. My guess is quite a few. Among '70s radicals like Boudin, and even among less violent leftists, "pig" was a common term for police officers—especially after the street battles outside the 1968 Democratic National Convention, during which Chicago police beat up a slew of protesters. Of course, the expression wasn’t limited to cops; it encompassed vast numbers of people and professions. Capitalist pigs. Fascist pigs. Unfortunate pigs. Former Weather Underground leader Bernadine Dohrn famously expressed delight in 1969 over the mutilations of the Hollywood "pigs" killed by Charles Manson and his followers.

Many left-wing zealots considered pigs, however defined, an undesirable class. Some police officers and others died as a result of their antipathy. A Brink's security guard was shot dead by Boudin’s gang minutes before it killed two police officers in a hail of bullets. Bystanders were sacrificed to the war on pigs, as well. Robert Fassnacht, a postdoctoral student, was killed when radicals bombed the University of Wisconsin in 1970. Myrna Opsahl, a mother of four, was reduced to collateral damage in a bank heist by the Symbionese Liberation Army.

Of course, it’s possible to claim that language that defines certain people as subhuman, or that marks the lives of others as blunt obstructions to the attainment of justice, or of a grand and noble cause, has no real-world significance. You can claim that the self-styled revolutionaries who shrieked "Kill the pigs!" at rallies in the early '70s were merely employing a bit of hyperbole. You can contend that not even the most deluded campus narcissists, those with the most romantic attachment to radical violence, and not even the most manipulative thugs, those for whom the revolution was an opportunity to steal some cake and eat it too—that none of them took such language seriously.

Similarly, there is no provable link between the hysterical right-wing rhetoric of the 1990s and right-wing terrorism. One could call federal agents "jackbooted thugs" intent on crushing the people’s liberty, as former National Rifle Association leader Wayne LaPierre did in 1995, and still deny that there’s any link between the nation’s most prominent gun lobbyist demonizing federal employees and an obscure gun nut blowing them up, as Timothy McVeigh did that year in Oklahoma City.

In fact, you can deny a connection between rhetoric and action every time. Just as Bill O’Reilly is doing now.

O’Reilly came out guns blazing at his critics in the wake of the murder of Kansas abortion doctor George Tiller. The doctor’s murder was not, in O’Reilly’s view, a net positive. But blaming O’Reilly for contributing to it was the greater outrage. It was—as it is ever and always with O’Reilly—a slander by elite liberals, amoral liberals, and the liberals’ very liberal enablers in the liberal press.

O’Reilly himself had nothing to apologize for.

Not the 29 episodes of his show on which he specifically targeted "Tiller the Baby Killer" as indifferent to human life and a menace to society.

Not his accusation that Tiller "destroys fetuses for just about any reason right up until the birth date for $5,000."

Not his contention that Tiller’s legal abortion practice was "the kind of stuff" associated with "Hitler’s Germany."

Not his characterization of Tiller’s practice as a "death mill."

Not his claim that "anybody" who allowed Tiller’s practice to continue "has blood on their hands."

Why should O’Reilly apologize? It was just talk, which is what he does for a living. And every one of his verbal assaults on Tiller was constitutionally protected talk at that. So O’Reilly has committed no crime. He can’t be blamed for Tiller’s death. He can’t be blamed for anything. It’s just the unpredictable nature of the world. Pigs die.