A state of war exists only after a declaration of war. This declaration is the dividing point between war and peace. If a country is in a state of war, the war of law binds the belligerents, as well as particular rules of domestic law that refer to a state of war or a time of war. New war terminology and new categories of war, emerging from political practices, resulted in confusion and legal uncertainty about the status and the consequences concerning military personnel participating in international peacekeeping missions. The trial of Eric O is a case in point. The Court of Appeal's severe criticism towards the Public Prosecution Service and the Ministry of Defence about this subject underline the problematic character of the lack of legal knowledge and the unanswered question of what rules apply in international missions.