The Legality of the Use of Force against Islamic State

The aim of this thesis is to evaluate the lawfulness of the use of force by the United States of America against the so-called Islamic State in the territory of Syria, in terms of Ius ad bellum. For this purpose, the thesis is divided into three parts. The first part focuses on assessing the subjectivity of the Islamic State. In particular, the subjectivity is examined with regard to the criteria arising from the Montevideo Convention on the Rights and Duties of States and from professional experience. The Islamic State is assessed in terms of defined territory, permanent population, effective government, capacity to enter into relations with other states, independence and legitimacy. The second part deals with the legal regulation of the use of force in international relations. After the presentation of the historical development, the attention is paid especially to the UN Charter and the ensuing prohibition of the threat or use of force in international relations. In the context of the use of force against the Islamic State, legal exceptions to this prohibition, which could be used in the fight against the Islamic State, are presented. First, attention is paid to the exceptions resulting from the UN Charter, which are self-defense under Article 51 and actions under Chapter VII. Two types of..