The Ex Post Facto Principle in International Criminal Law: To Observe Impossible to Violate?

The present article analyses the content of the principle of non-retroactivity in international law and the main legal acts where the ex post facto principle is fixed. The problems of the application of the ex post facto principle in international law are examined, considering the specificity of its content as well as the historical context that raised the issue of the possibility of derogating from this principle. In conclusion, an author finds out the scope where the implementation and application of the principle of non-retroactivity in international criminal law will have its specific features compared with national law.