Use of force

When conflict could not be prevented, parties may have recourse to what in diplomatic language is euphemistically referred to as the ‘use of force’ – armed conflict and war. Some preliminaries will have to be addressed first: how to approach the question of the use of force? how does diplomacy relate to it? how does the current security landscape look like? After these preliminaries, the substance of the matter can be dealt with. We first distinguish the different forms of use of force: in self-defence, in response to an external threat or to an internal threat. Armed conflict – war – is not a free for all: there are questions of legality, legitimacy, and prudence to be addressed when launching a war (jus ad bellum), no less than in its actual conduct (jus in bello). These questions lay at the basis of the distinction between wars ‘of choice’ and wars ‘of necessity’. But how they work out in practice is far from obvious. In this context, we also discuss the United Nations Security Council’s crucial role in authorising (or not) the recourse to the use of force. When war is over, we get peace, but peace comes in many shapes ranging from ‘deficient’ to ‘perfect’. We will look at these. We will also briefly review the main causes of and reasons for war. We close the chapter by studying two extremes of warfare: nuclear war and hybrid war.