Back when some folks on the right (myself included, though the posts have vanished into the ether) were griping about the absence of a critical, substantive liberal response to Ramesh Ponnuru's Party of Death - and yes, I know, the title was inflammatory, and books with inflammatory titles don't deserve to be read, etc. etc. - someone responded (again, in a post I can't find) that they already knew what the pro-life arguments were on abortion, they'd heard the debate a hundred times before, and unless Ramesh's book had discovered some new, as-yet-unconsidered argument against feticide and embryo-killing, it was just the same old song, and they didn't need to hear it again.
Now of course The Party of Death covered all sorts of ground beyond the "is it murder/should it be legal?" debate - but even setting that aside, I would find the "nothing new to see here" line much, much more convincing if it didn't appear that no less eminent a figure than Garry Wills, who boasts a long career as a (Catholic!) public intellectual on the front lines of the culture war, seems to seriously believe that it's worth his time to explain to abortion opponents that the pro-life principle is mistaken because "harvesting carrots, on a consistent pro-life hypothesis, would constitute something of a massacre."