While Clausewitz s theoretical framework was instrumental in dealing with modern wars, the undrestanding of the use of force on behalf of the internacional community is still in urgent need of a working theory. In 1945, the preamble of the Charter of the United Nations, while emphasizing the determination to save future generations from the scourge of war, established a clear dichotomy between good, represented by peace, and evil, represented by war. Nevertheless, the attempt to avoid wars between states and to protect populations ended up creating the conditions of possibility for the use of force on the behalf of the international community. The phenomenon of the use of force on behalf of the international community is therefore somewhat new. It has been mainly characterized by contemporary robust peacekeenping, humanitarian interventions, and (even more recently) responsibility to protect (R2P). Inspired by a Clausewitzian approach and introducing concepts such as abolute peacekeeping and thrinity, the present doctoral dissertation proposes a theoretical framework to understand the use of force on behalf of the international community. It also applies the proposed theoretical framework in order to understand two recent events: the UN peacekeeping operation in Haiti (MINUSTAH) and the 2011 intervention in Libya.