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Spare No One? A Review Essay


This essay considers some central arguments given by Helen Frowe and Seth Lazar regarding the permissibility of killing civilians in war. It raises some objections to their views and defends some alternative bases for weighing harms to combatants against harms to civilians.

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  1. Jeff McMahan’s views are laid out most fully in Killing in War (Oxford: Oxford University Press, 2009).

  2. Helen Frowe, Defensive Killing (New York: Oxford University Press, 2014) (hence referred to as “DK”); Seth Lazar, Sparing Civilians (New York: Oxford University Press, 2015) (hence referred to as “SC”).

  3. See Jeff McMahan’s and Henry Shue’s papers on “Laws of War,” (Chapters 24 and 25, respectively) in The Philosophy of International Law, eds. Samantha Besson and John Tasioulas (Oxford: Oxford University Press, 2010). See also Jeff McMahan, “War Crimes and Wrongdoing in War,” in The Constitution of the Criminal Law, eds. R.A. Duff, Lindsay Farmer, S.E. Marshall, Massimo Renzo, and Victor Tadros (Oxford: Oxford University Press, 2013).

  4. Here and elsewhere, I assume the following straightforward definition of liability: X is liable to being killed by Y iff X lacks a right that Y not kill him (or, in other words—and I assume this to be equivalent—X would not be wronged by Y if Y kills him).

  5. David Rodin, “The Moral Inequality of Soldiers: Why Jus in Bello Asymmetry is Half Right,” in Just and Unjust Warriors, eds. David Rodin and Henry Shue (New York: Oxford University Press, 2008), 44–68.

  6. Alan Gewirth, “Are There Any Absolute Rights?” Philosophical Quarterly 31(122) (1981): 1–16.

  7. Thomas Scanlon, “A Theory of Freedom of Expression,” Philosophy & Public Affairs 1(2) (1972): 204–226, at 213.

  8. John Gardner, “Complicity and Causality,” Criminal Law and Philosophy 1(2) (2007): 127–141.

  9. Alan Gewirth gives a similar motivation for his stronger principle.

  10. This case derives from one discussed by Cheney Ryan, “Self-Defense, Pacifism, and the Possibility of Killing,” Ethics 93(3) (1983): 508–524.

  11. Thanks to Helen Frowe for raising this objection.

  12. Crimes that, let’s suppose, are also clearly moral wrongs, such as harming the innocent, rather than, say, selling drugs or facilitating gambling.

  13. U.K. Ministry of Defence, The Joint Service Manual of the Law of Armed Conflict, available online at at 24.

  14. This still leaves Seth Lazar’s important puzzle of what to say about combatants who are, say, ineffectual and thus contribute little to the threats their country poses. Aren’t they also lacking in responsibility? I won’t address this issue here, but see the discussions of combatant (non)immunity in Helen Frowe (DK, Chapter 7) and Seth Lazar (SC, Chapter 6).

  15. Although there is this difference between them: Helen Frowe claims that only non-combatants are innocent/non-liable, while Seth Lazar claims that some combatants are too.

  16. Though Helen Frowe points out that these killings would have to be proportionate to be acceptable; they would have to produce a substantial benefit (DK, 197). According to Helen Frowe, this will rarely be the case, but see Seth Lazar’s many examples of attacks on civilians that had a major impact on the course of a conflict (SC, Chapter 2).

  17. Note that this principle is formulated much more carefully in the book than in my presentation—for instance, in its specification of the precise kind of probability that is relevant. These subtleties don’t make any significant difference to my discussion.

  18. “General Bugeaud pursued a scorched-earth policy in the Algerian interior, designed to undermine popular support … Men, women, and children were killed, and officers were told to take no prisoners. Any of Abd al-Qadir’s men who tried to surrender were simply cut down.” Eugene Rogan, The Arabs: A History (New York: Basic Books, 2009), 117–118.

  19. Perhaps the introduction of ethnicity complicates the example because there is something especially bad about systematically targeting a particular group. (See, for instance, Massimo Renzo’s overview of targeting collectives in “Crimes Against Humanity and the Limits of International Criminal Law,” Law and Philosophy 31(4) (2012): 443–476.) In that case, imagine that our killer doesn’t aim to kill any particular group: she has decided that the world is simply overpopulated and eradicates large numbers of innocents because she hates having them around. I still find this no easier to justify than an opportunistic killing, and perhaps rather worse.

  20. See, for instance, Alan Hájek, “The Reference Class Problem is Your Problem Too,” Synthese 156(3) (2007): 563–585.

  21. It might be said here that when it comes to preventing compromised relationships what really matters is conditional vulnerability. For as long as others have the capacity to really damage me, then I am relying somewhat on their goodwill not to harm me and will thus always be somewhat concerned to avoid drawing their ire. I think this shows that conditional vulnerability matters. But unconditional vulnerability can still matter too: if someone powerful makes a genuine commitment not to harm me and I trust her, this does provide with me some worthwhile extra security, despite being a product of her decision. Also, there is little that can be done to reduce non-combatant dependency of this kind: short of arming them (and turning them into combatants), they will always be reliant on the restraint and protection of the powerful for their own security.

  22. Joseph Heller, Catch-22 (New York: Simon and Schuster, 1955), 25.

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Correspondence to Adam Omar Hosein.

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Hosein, A.O. Spare No One? A Review Essay. Criminal Law, Philosophy 13, 187–203 (2019).

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  • Self-defense
  • War
  • Civilians