Firstly, it is widening of the scope to the groups which are not under direct control of a state, as required by the International Court of Justice in Nicaragua case. Secondly, the problems arise as to what actions are justified in self-defense. Thirdly, the issue of preventive self-defense arises, especially after the 2002 US National Security Strategy widened its application far beyond limits set by customary and case law. Three case studies will illuminate several legal and political aspects of law of self-defense at the beginning of the 21st century.

Research paper was originally prepared for the conference Global Security in Obama’s Age held on April 9, 2010 in Prague.