III.  ACCOUNTABILITY AND THE RIGHTS OF VICTIMS armed conflicts, all States have the responsibility to respond to grave and other breaches of the Geneva Conventions and of Protocol I. Under the Geneva Conventions, States undertake the obligation to respect and to ensure respect for the Conventions in all circumstances. Specifically, States undertake to enact legislation to provide effective penal sanctions for perpetrators of grave breaches of international humanitarian law. In contrast, neither common article 3 nor Protocol II makes specific provision for the prosecution of serious violations of their rules or for grave breaches. However, the jurisprudence of the International Criminal Tribunal for the former Yugoslavia and the International Criminal Tribunal for Rwanda has established that war crimes may also be committed in non-international armed conflicts.121 Moreover, taking into account the complementary nature of the International Criminal Court’s jurisdiction, the inclusion in its Rome Statute of war crimes committed in non-international armed conflicts means that States also have an obligation to investigate and prosecute serious violations of common article 3 of the Geneva Conventions, as well as other serious violations of the laws and customs applicable in armed conflicts not of an international character.122 The International Court of Justice dealt with the obligation to prevent and punish genocide. It determined that “one of the most effective ways of preventing criminal acts, in general, is to provide penalties for persons committing such acts, and to impose those penalties effectively on those who commit the acts one is trying to prevent.” Furthermore, the Court recalled that, under the Convention on the Prevention and Punishment of the Crime of Genocide, States parties have an obligation to “arrest persons accused of genocide who are in their territory—even if the crime of which they are accused was committed outside it—and, failing prosecution of them in the parties’ own courts, that they will hand them over for trial by the competent international tribunal.”123   See, in particular, Prosecutor v. Duško Tadic´, paras. 86–136.   Rome Statute, art. 8.2 (c) and (e). 123   Application of the Convention on the Prevention and Punishment of the Crime of Genocide, paras. 426 and 443. 121 122 83