No matter which side of the abortion debate you stand on, the murder of Dr. Tiller is an appalling end to a human life. The fact that he himself has ended a number of innocent lives through his daily work does not matter: Whatever you may think of the man, he was acting within the bounds of the law of the land.
When anti-abortion advocates say that Dr. Tiller "had it coming", they are taking the position that their God's will has been done. They are offering their support to the murderer who decided to take the law in his hands imagining that god is on his side. This is what happens when men decide to bypass the legal confines of society in pursuit of their idea of justice.
When such events take place, then, some people carry more responsibility than others for fostering a climate in which these tragedies can take place. One such person is Frank Shaeffer, son of the late evangelical leader Francis Shaeffer. He takes responsibility and apologises for lending his mind in support of the atmosphere that made Dr. Tiller's murder possible.
When you hear someone condemn Dr. Tiller's activities or justify his murder with platitudes like "you live by the sword", or "you shall reap what you have sown", remind them that Dr. Tiller no more had it coming than a lawyer who defends a murderer or an aviator on the Enola Gay or a worker at a slaughterhouse. The world is full of people who perform a job despised by a part of the population, more or less strongly. Imagine what would happen if anyone armed with unshakable beliefs in a particular worldview, a self-appointed executioner of immoral men, decided to take matters in his hands to right what he sees as an abominable wrong.
This episode also highlights a fact which is more typical of the United States than of almost anywhere else in the civilized world: The widespread and largely unchecked availability of firearms, while legal, constitutes a clear and present danger to those of us who choose to live peacefully and seek reasonable means of conflict resolution through the available legal channels. It also reinforces the feeling in predisposed subjects that the law is a subjective domain, to be administered by those who are ready to act according to a superior sense of morality derived from divinity and/or superstitious beliefs.