Abstract

Kieran Oberman argues that there is no such thing, in realistic circumstances, as an optional war, i.e. a war that it is permissible for a state to wage, but not obligatory. Regarding a central kind of war – humanitarian intervention – this is due to what Oberman calls the Cost Principle, which says that states may not impose humanitarian costs on their citizens that those citizens do not have independent humanitarian obligations to meet. Essentially, this means that if the seriousness of a humanitarian crisis is sufficient to justify imposing a certain level of cost, it must be serious enough to ground a genuine obligation to intervene. This paper offers three cases where, even if we accept the Cost Principle, war may be reasonably described as optional. These include the state’s moral relationship to amassing support for voluntary contributions to a war that would otherwise exceed the threshold established by Cost Principle (the Voluntary War); a war where it is uncertain whether costs will exceed the threshold (the Forever War); and two wars whose costs would individually fall below the threshold, but which would collectively fall above it. While none of these examples is conclusive, I conclude that Oberman must defend some further, contestable moral claims to establish that the optional humanitarian war is a myth. The Cost Principle alone does not get us there.