The Challenge to Jus ad Bellum Posed by the Development or Use of CBRN Weapons

A widespread debate has arisen on the lawfulness of military interventions to counter the proliferation of CBRN weapons and prevent their use against combatants and civilians. widespread debate has arisen on the lawfulness of military interventions to counter the proliferation of CBRN weapons and prevent their use against combatants and civilians. Some authors have judged such a debate useless.1 They believe that jus ad bellum has become ‘paper rules’, ie ‘rules that lay out aspirational goals for the management of state-sponsored force rather than binding precepts of international law’ (Glennon, 2013). Moving from the opposite opinion, this contribution assumes that the rules prohibiting the use of force are still alive and have not lost their compulsory nature. Against this background, the present chapter will examine whether State practice concerning the development and use of CBRN weapons has brought (or is in the process of bringing) the emergence of new rules allowing States to use military force with the limited aim of preventing the occurrence of imminent or possible CBRN attacks against them or thwarting their use against civilians and combatants.