The project aims to examine the interplay between international law, EU law and the Instrument of Government in the area of international military force. The project will examine the official interpretation of the Constitution's provisions on self-defense and the sending of Swedish troops abroad for other purposes, in light of the intensified Swedish participation in various international defense-related cooperation and in international military operations of various kinds and on various international law grounds. The project will analyze the provisions concerning "Defence of the Realm" (RF Chapter 15, Section 13) and "Deployment of Armed Forces" (RF Chapter 15, Section 16). The research in the project takes place against the background of the conflicts in Iraq and Syria and the Swedish involvement in various forms in these conflicts, but examples will also be taken from other conflicts, e.g. in Afghanistan, Libya and Mali. The deepened defence cooperation with Finland raises questions about collective defence arrangements of various kinds within the framework of the Instrument of Government. What scope is there for collective defense arrangements, either non-legally binding arrangements such as those envisaged with Finland or binding arrangements as in the case of the EU Treaty Article 42(7)? The legal - and real - question of when Sweden can go to war arises both in the case of international operations and in the case of collective self-defense. "War and danger of war" in the sense of the Instrument of Government is once again being taken seriously.