HT: Thoughts of a Regular Guy
Why the analogy to slavery, or Hitler? It's inflammatory, and rarely advances the debate. Such analogies too often degenerate into "Hitler was a vegetarian too, you tofu-eating Nazi!!!*"
But in this case, I think the analogy to slavery is important, for two reasons. First of all, it was the last time we had an extended, society-wide debate about personhood. And second of all, as now, there were structural political reasons that it was much harder--nearly impossible--to change slavery through the existing political process.
Listening to the debates about abortion, it seems to me that really broad swathes of the pro-choice movement seem to genuinely not understand that this is a debate about personhood, which is why you get moronic statements like "If you think abortions are wrong, don't have one!" If you think a fetus is a person, it is not useful to be told that you, personally, are not required to commit murder, as long as you leave the neighbors alone while they do it.
Read it all!
And keep in mind, the vast majority of prolifers -- even those who figure the murder was an instance of "good riddance to bad rubbish" -- believe shooting Tiller was wrong. That the killer should be positively identified by a proper trial and punished according to the law. Because society is based on justice, not on vigilantism and not on killing people just because you find their presence troubling.
We can recognize what Tiller did as abominable and still not want him to have been gunned down, just as opponents of capital punishment can recognize what a death-row inmate did as abominable and still not want him to be executed.