Is there a moral difference between killing a newly born baby and having an abortion? To be consistent, do we have to say either abortion/infanticide is morally wrong OR that abortion/killing a newborn can be morally permitted if the circumstances are right?

The answer to your question depends in part on whether and how the moral status of a fetus differs from the moral status of an infant. One might reasonably think, for example, that there is no significant difference in moral status between a fetus the day before its born and an infant the day after its born. The only difference seems to be one of residence: one resides inside a uterus, and the other resides in a hospital's maternity ward. And we don't normally think that where one lives is especially relevant to one's moral status. Thus, if it's wrong to kill one, it must be wrong to kill the other. That said, one might also reasonably think that there is a significant difference in moral status between an embryo that is only two weeks old--a cluster of cells that looks something like this --and a newborn baby. And if there is a significant difference in moral status, then it is perfectly consistent on one hand to defend the right to have early-term abortions but on the other to oppose...