The British philosopher G. E. M. Anscombe, in a brilliant essay [“Modern Moral Philosophy”] in 1958, pointed out that somewhere between John Stuart Mill in the nineteenth century and G. E. Moore in the twentieth, the British utilitarian tradition lost the ability to assert that the taking of innocent life is wrong. Anscombe also predicted that there would eventually come along someone willing to say that we should kill babies because utilitarianism offers no explanation of why we shouldn’t. Anscombe intended this as the final rejection of utilitarian ethics—for, after all, killing babies is wrong, and a moral theory that arrives at the contrary conclusion must be mistaken.

But with Princeton University’s Peter Singer, among others, we finally have utilitarians who have abandoned the last vestiges of cultural Christianity that skewed the purely philosophical structure of their ethics. They have accepted Anscombe’s dilemma by denying that the taking of innocent life is always wrong. “John Paul II proclaims that the widespread acceptance of abortion is a mortal threat to the traditional moral order,” Singer wrote in “Killing Babies Isn’t Always Wrong,” a 1995 article in the London Spectator. “I sometimes think that he and I at least share the virtue of seeing clearly what is at stake.” For a believer, all of this demonstrates that there is nothing in the liberal philosophical tradition that can be counted upon to preserve, unaided by faith, the sanctity of innocent life.

(Joseph Bottum, "Social Conservatism and the New Fusionism," chap. 2 in Varieties of Conservatism in America, ed. Peter Berkowitz [Stanford, CA: Hoover Institution Press, 2004], 31-47, at 44)

Note from KBJ: It's worse than Bottum makes it sound. Singer doesn't just deny that killing innocent human beings is absolutely wrong (i.e., wrong without exception); he denies that killing innocent human beings is intrinsically wrong (i.e., wrong in and of itself, independently of its consequences). To Singer, the fact that an act is an act of killing an innocent human being is morally irrelevant. All that matters to him are the consequences of the act.