[O]ne condition of immunity to violence is that one not be participating in an attempt on the lives or the bodily security of other innocent persons; and the terrorist ex hypothesi is so participating: he is, at the very least, deliberately allowing innocent persons to be killed and mutilated by withholding his knowledge; and if he had a hand in placing the bombs, he is allowing the consummation of murders and mutilations he himself has set in train. Until the nineteenth century, positive law and moral opinion joined in permitting torture in such a case. In the past century and a half, torture has come to be prohibited by law in all civilized countries; and rightly, because it has been found practically impossible, while allowing it at all, to confine its use to the very few cases in which it would be morally permissible.

(Alan Donagan, “Cases of Necessity,” chap. 4 in Absolutism and Its Consequentialist Critics, ed. Joram Graf Haber [Lanham, MD: Rowman & Littlefield Publishers, 1994], 41-62, at 57 [essay first published in 1977])