The text reproduces the keynote address, delivered by the author at an event marking the national Constitutionality Day, held on 18 December 2025 at the Constitutional Court of Slovenia in Ljubljana. The address reflects on the principles of rule of law, equality before the law and respect for international law as some of the key values enshrined in the Slovenian Constitution. The first part discusses the development and achievements in international criminal law over the past 80 years, focusing on three key aspects: institution-building, the growing importance of domestic prosecution and adjudication of international crimes and strengthened efforts at codification. It then turns to the challenges faced by international criminal courts and tribunals and international law more generally. The author discusses the unprecedented attacks and political pressure directed at the judges of the International Criminal Court and notes that judicial independence is a cornerstone of the rule of law and should be vigorously defended. International law, regional human rights instruments and the Constitution are complementary building blocks of the rule of law at both national and international levels. Strong and independent domestic courts strengthen international justice, whilst strong and independent international courts strengthen rule of law at the national level.
Key words: Constitution of the Republic of Slovenia, international law, international criminal law, international courts and tribunals, International Criminal Court, Nuremberg Trials, rule of law, judicial independence, codification of international law, international crimes.