This work reconsiders and critically evaluates the complex international legal framework which seeks to regulate wars of national liberation in the light of two fascinating case studies. It tests the effectiveness of both the jus ad bellum and jus in bello aspects of the current legal framework by applying it to self-determination wars waged in the South Moluccas and Aceh by armed groups against Indonesia. The book highlights the various difficulties inherent in the current legal framework as well as the ad hoc and unpredictable practice of States in relation to its application. The work concludes with recommendations on how the current framework should be updated and enhanced so that it can adequately deal with modern self-determination conflicts.