The Use of Force in International Law

War and other forms of collective violence have been omnipresent in human history. While the ideaof perpetual peace has always been an aspiration since time immemorial, the rejection of aggressionto resolve international disputes is peculiar only to modern times. Indeed, only after World War IIhad the international community prohibited unilateral aggression. While the rules regulating the useof force are of critical importance in international law, the  political dynamics of internationalrelations   often   engender   self-interested   conduct   apropos   security-related   matters.  Thus,   themaintenance of international peace and security is in large measure hinged on the control andrestriction of military force. After examining the evolution of the laws governing use of force underthe League and United Nations systems, this Chapter will argue that despite the emergence of newthreats to international security, stemming from new actors and modern military technologies, theinternational community must remain attentive to unjustified attempts to downplay the principles ofjus ad bellum.