"In each of the contexts discussed so far—the military, capital punishment, and assisted suicide—there are of course different views as to whether the killings in question are morally permissible. Yet there is essentially no room for debate that each of these contexts involves the killing of other human beings. In short, the debate is over the morality or permissibility of the killing, not whether a killing takes place at all. The context of abortion, of course, is different. In Roe v. Wade, the Supreme Court famously declared itself unable to determine when human life begins: “[T]he judiciary, at this point in the development of man’s knowledge, is not in a position to speculate as to the answer.” Thus, in some ways the abortion debate is about whether abortion is killing at all, with some abortion supporters arguing that abortion does not involve killing, and abortion opponents arguing that it does. This dispute over whether abortion is a killing in the first place adds a difficulty that is not present in the other contexts where the fact of killing is agreed upon, and the only questions concern the permissibility of that killing. Nevertheless, despite this additional level of dispute, the abortion context offers the most systematic and all-encompassing example of government efforts to ensure that unwilling individuals are not forced to engage in what"