When should international humanitarian law (IHL) apply? When should it prevail over, and when should it give way to international human rights law (IHRL) in regulating the conduct of hostilities during international and non-international armed conflicts? IHL and IHRL give diverging answers to the crucial question of when it is legally permissible to kill another person. Following the customary IHL principles of distinction, proportionality and necessity systematically leads to breaches of the legal provisions safeguarding the human right to life. Some legal scholars, notably Helen Duffy in this volume, do not acknowledge this norm conflict, but aver that the two bodies of law can be reconciled through interpretation. Those that reject a substantive convergence between IHL and IHRL tend to take one of three broad positions: many argue that the norm conflict can be resolved by reference to lex specialis; others suggest that, in each instance, the rule should prevail that affords greater protection; yet others cast the matter as depending on which rules states intended to apply in a given context.