What Northam, Obama, and Tran have all demonstrated is that the line between abortion and infanticide is blurry, and politicians zealously committed to the former are liable to cross it. While infants are usually at a more advanced stage of development than fetuses, what distinguishes each group from the other as a class is not that fact. An individual infant who was born very prematurely is less developed (often substantially so) than a fetus at term, but it is the former who has legal protection. The distinction turns entirely on location: Inside the womb the developing human organism is a fetus, and outside it an infant.

The Supreme Court’s abortion juris­pru­dence compounds the confusion because it purports to turn on stage of development but actually turns on location. The Court’s rulings are often thought to require abortion to be legal early in pregnancy but to allow prohibitions later, and it has often claimed that the government’s interest in protecting un­born life increases with fetal age.