States exercising considerable influence in the international realm have condemned the International Criminal Court’s investigations into alleged wrongdoing by their citizens during times of conflict. To do so and enact barriers against ICC investigations threatens the sole international mechanism by which governments and their citizens may be held accountable for war crimes and grave breaches. This article considers in what circumstances the International Criminal Court can hold citizens of Third States accountable for actions that may violate the Geneva Conventions and asserts that the ICC may exercise jurisdiction over citizens of Third States – even without a referral from the United Nations Security Council – due to the development of the prosecution of such crimes into jus cogens. In addition to the jus cogens nature of the prosecution of war crimes and grave breaches, the ICC may also exercise universal jurisdiction due to its legal personality. The protestations against ICC investigations into alleged war crimes by citizens of Third States, such as the United States’ condemnation of the ICC investigation into its servicemembers’ activities in Afghanistan, cannot prevent the ICC from completing its directive due to the international legal authority of universal jurisdiction and jus cogens.