The Rome Statute of the International Criminal Court completely divests the Court of the power to compel a state to disclose evidence in its possession if the state opposes such disclosure on grounds of national security. If a state refuses to disclose information essential to the adjudication of a case on national security grounds, the ICC may settle fair trial concerns either by drawing factual inferences favourable to the defendant or by staying the proceedings. I argue, however, that in practice such judicial powers do not provide a sufficient guarantee of a fair trial. I propose to allay fair trial concerns arising from the refusal of states to allow the ICC access to evidence in their possession by introducing a reform in the exercise of the ICC's prosecutorial discretion. According to my proposal, the requirement of a fair trial, which entails the disclosure of material essential for the defence, would be incorporated into the criteria that guide the ICC Prosecutor in the selection of cases for prosecution. Although the present article focuses on the issue of national security evidence, the reach of the proposed reform extends to all cases of state refusal to allow the ICC access to evidence, regardless of the grounds for refusal.