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This review essay examines Benbaji and Statman's War by Agreement. It raises two challenges to their contractarian account of war, which seeks to show that considerations of mutual advantage can generate novel permissions. First, if such a robust justification for participation in unjust wars is available, it is not clear that any kind of agreement between states is even required; if a state can make otherwise unjustified killings permissible, it would seem to be able to do so without the participation of other states. Second, more generally, I doubt that any such agreement could make otherwise unjustified killings permissible.

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  1. For example, David Gauthier, Morals by Agreement (Oxford, Oxford University Press, 1986)

  2. Raz, for example, argues that authoritative directives, including both rules and rights, provide a service by enabling people to better conform to reasons that apply to them apart from those rules.

  3. Applbaum, Ethics for Adversaries (Princeton, Princeton University Press, 1999),.

  4. Yuan Yuan, Public War: Restoring the Political Nature of Warfare, unpublished doctoral dissertation, Yale University, 2020.

  5. If capital punishment is never justified, then the executioner is no more of a murderer in this than in any other case.

  6. e.g. Sumner, The Moral Foundations of Rights (Oxford, Oxford University Press, 1987)

  7. Thomas Hurka, “Liability and Just Cause,: Ethics and International Affairs 21 (2):199-218 (2007)

  8. Seth Lazar Sparing Civilians (Oxford, Oxford University Press, 2015)

  9. Christian Wolff, Jus Gentium Methodo Scientifica (Frankfurt and Leipzig: Societas Veneta, 1764), for the English translation, see Christian Wolff, Jus Gentium Methodo Scientifica (Joseph H. Drake trans., Oxford: Clarendon Press, 1934), 2:402.

  10. Hugo Grotius, de iure belli ac pacis 1625, translated by William Whewell as On the Laws of War and Peace (Cambridge: Cambridge University Press, 1853). Book III ch. 11.

  11. For a contemporary statement of a similar contrast between impunity and justification, see Adil Haque, Law and Morality at War (Oxford: Oxford University Press, 2017).

  12. Emerich de Vattel, Le Droit des Gens, ou Principes de loi Naturelle, Appliques à la conduite & aux affaires des Nations & des Souverains, London: Chez Benjamin Gibert 1758, translated as The Law of Nations, Or, Principles of the Law of Nature, Applied to the Conduct and Affairs of Nations and Sovereigns, edited and with an Introduction by Béla Kapossy and Richard Whatmore (Indianapolis: Liberty Fund, 2008) Book III, ch. III, par. 33.

  13. Kant, Rechtslhere, translated as The Doctrine of Right, by Mary Gregor in Kant, Practical Philosophy (Cambridge: Cambridge University Press, 1996) 6:307.

  14. Hersch Lauterpacht, “Recognition of States in International Law,” Yale Law Journal, 53:3 (1944), 385-458, at 388.


  15. Benbaji and Statman refer to Andrew Sepielli, “Along an Imperfect Lighted Path: Practical Rationality and Normative Uncertainty” (PhD Dissertation, Rutgers University, 2010) p. 66. Sepielli has developed his position further in a series of more recent articles.

  16. Seth Lazar, Sparing Civilians, (Oxford: Oxford University Press, 2015) Ch. 2.

  17. Bearing in mind that aggressors also use defensive weapons to stop defenders from attacking them.

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Correspondence to Arthur Ripstein.

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An earlier version of this paper was presented at a workshop on War by Agreement at the University of Toronto in December 2020, where Yitzhak Benbaji and Danny Statman provided an illuminating response. I am grateful to an anonymous referee, Janina Dill, and Cecile Fabre for helpful written comments on an earlier draft.

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Ripstein, A. Disagreement by War. Law and Philos 41, 763–784 (2022).

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