The Use of Force and International Law

The purpose of this chapter is to provide some focused discussion on the meaning of the ‘force’ prohibited in Article 2(4) and customary international law. In seeking to expose the uncertainties in regards to this particular term, various factors or common elements of ‘force’ are distilled. After looking at the prohibition of force in the context of the principle of non-intervention, the chapter then moves on to look at the type of force that the prohibition is concerned with and, concluding that it is ‘armed force’, then moves on to attempt to distil the key elements of such force, including whether a weapon must be used and whether force can be used indirectly. The chapter then addresses the ‘gravity’ or severity aspects of a use of force, in particular by distinguishing it from an armed attack or act of aggression, but also by examining whether there is a level of force – or de minimis threshold – below which an action falls out of the remit of the prohibition. In this context, a distinction will be drawn between uses of force and law enforcement measures. Finally, and having distilled the key practical components of a prohibited use of force, the chapter focuses upon the mens rea component.