As with any judicial mechanism, the International Criminal Court (ICC) will conduct its operation within the framework of a number of rules and will provide its functions with these rules. The rules relating to the substantive law and procedural law that will be taken while the activities of the court are carried out and the settlement of the dispute will depend on the concept of the applicable law in the court. It is of great importance in terms of the rights of the defendants that determining what criteria the judgement will be taken. Although the committed crimes are serious crimes against humanity, they are a prerequisite for the fair trial and the predictability of the rules of law.
Article 21 of the Rome Statute has laid out the legal sources to which the ICC may apply. In this article; A total of seven sources have been presented, including four specific and “applicable international agreements, principles and rules of international law and general principles of law”, including ” this Statute, elements of crimes and its rules of procedure and evidence”. The sources we refer to as “private sources” are only those regulated by the ICC. So the origin of these is the ICC. The sources we refer to as “general resources” are the sources that form the basis of international law. Before the existence of the ICC, they were in the world of international law.
The question of applicability is solved more easily in national laws due to the jurisdiction of a single state. However, there are some problems in international criminal law as more than one state has a role in determining the jurisdiction and the sources. The applicability of the ICJ’s jurisdiction has been tried to be solved by the provisions of the Rome Statute, but the very detailed discussion of such regulations has led to the need for interpretation of these rules. For example, the fact that there are too many procedural rules in the Statute and the detailed arrangement of the elements of the crime reveals the question of how these rules should be interpreted and applied. It is contemplated that the question of applicability in international criminal law will be examined by comparing it with the ICC case-law and national law. It must be noted that an international court can handle any case. What matters is not its functioning and ultimately making a decision; to be able to make a decision in a fair way that ultimately relieves the conscience of the international community. In this respect, it is of utmost importance that the applicability problem is resolved so that ICC can make fair decisions. This research shows that international justice systems can benefit from regulations national justice systems. The research will contribute to a better quality of justice in international systems, and lead to improved fair trial rights for defendants, better procedural protections for victims, and enhanced justice outcomes for affected communities.