Impunity refers to situations in which there are no effective measures to penalize violations or when such measures are not enforced. Impunity may result from a political decision and amnesty regulation or from a judicial system that functions poorly or is disintegrating.
Under international law, impunity most often results from the absence of judicial mechanisms that are capable of judging a failure to comply with established rules. The enforcement of penalties for crimes committed is primarily a responsibility of domestic jurisdictions. It is especially difficult to render justice on war crimes or crimes against humanity committed by government actors or people under their command in times of armed conflict. Another aspect is the transnational aspects to the perpetration of these crimes, for instance in the case when perpetrators try to avoid justice by fleeing to other countries.
Therefore, and to fight impunity, international and national criminal law establishes that certain crimes are not subject to any statute of limitations. This means that legal proceedings cannot be limited in time and can be initiated even if the acts remain unpunished for years. Also, heads of states and governments enjoy limited immunity. The International Criminal Court or domestic jurisdictions may—under certain circumstances—criminally prosecute them.
Humanitarian law imposes on all states the obligation to pursue the perpetrators of grave violations of the Geneva Conventions (war crimes) and to prosecute them, regardless their nationality. This is called the concept of universal jurisdiction. Furthermore, for such serious crimes, humanitarian law forbids that amnesties be granted at the time of negotiation of peace accords or under any other circumstance.