The Donald: exposing the true GOP.
This gives the whole game away. Pro-lifers know they cannot hope to win the argument if the woman seeking to end her pregnancy will also be seen in the eyes of the law as guilty of accessory to fetal homicide. Abortion might be murder, as the most vociferous pro-lifers argue, but it's the medics that carry it out who are the murderers, not the woman carrying the baby however defective her own moral code might be. This might be completely inconsistent with the law on homicide in every other case, but such are the compromises if you want to put a stop to women being "like their prenatal children, victims of our horrific abortion policy", as Charles Camosy has it in his piece for the New York Daily News.
Hence Trump is not a true pro-lifer in their eyes, as he isn't jumping through the ideological constructs they think necessary in order to eventually be able to punish women in precisely the way he suggested. And they're right, only for entirely the wrong reasons. Yes, he most likely doesn't believe a word he's saying, but he's saying it because it's what he thinks his base wants to hear. Those that do care don't go in for all this pious, oh, you can't blame the woman while doing precisely that half-way crap, they very much do blame the woman.
Trump's brilliance, or rather luck, has been in coming up with this formula at the precise moment when social media has made it possible to be unpleasant to almost everyone and still maintain a momentum that previously would have dissipated. It almost certainly won't win him the presidency, possibly not even the Republican nomination, but it has exposed the fissures in American politics and society both. In all the ironies of the 2016 presidential primaries so far, that it's a populist billionaire who has done the most to expose the failings of 35 years of Reagonomics has been the most delicious of all.