Chapter 4 shows that military necessity can affect the legitimacy of a belligerent act where the act is deemed evil and its purpose is considered legitimate. In no other circumstances, however, does an act’s legitimacy depend on whether it is materially necessary. As far as IHL norm-creation is concerned, the lack of material military necessity per se is never a reason for a belligerent act’s illegitimacy. If a warring party encumbers itself with missed opportunities and mounting blunders, it has only itself to blame. Nevertheless, in some circumstances, IHL does delegitimise exclusively self-inflicted evil, and it does mandate action with a view to reducing such evil.