This paper emerged from the Stockholm Centre for the Ethics of War and Peace's ‘Conversations on War’ series. We are grateful to participants at those workshops for helpful discussion. Versions of this paper were presented at the University of Birmingham Global Ethics Seminar; the LSE Choice Group Seminar; the University of Warwick Centre for Ethics, Law and Philosophy; the Moral and Political Philosophy Seminar at Australian National University; the Uppsala Women in Philosophy conference; the University of Melbourne Philosophy Department seminar; the University of Washington Philosophy Department seminar; and as a public lecture at the University of Southampton. For very helpful written comments and conversations, thanks to Avia Pasternak, Tom Parr, Derek Matravers, Bob Goodin, Al Wilson, Nic Southwood, Seth Lazar, Suzanne Uniacke, and Christian Barry. Thanks to two associate editors for this journal, whose comments significantly improved the paper. Work on this paper was supported by the Knut and Alice Wallenberg Foundation, Grant no. 1521101.