Divergent Views on the Content and Relevance of the Jus Ad Bellum in Europe and the United States? The Case of the U.S.-Led Military Coalition Against 'Islamic State'

Abstract

The goal of this chapter is to take a critical look at the alleged transatlantic divide with regard to the content and relevance of the jus ad bellum by means of a case-study, notably from the perspective of the recourse to force by the US-led military coalition fighting against the so-called Islamic State (IS, also known as ISIL, or Da’esh) in Iraq and Syria. At first sight, this case would seem to confirm the existence of such a divide, more specifically in relation to the legality of self-defense against attacks by non-State actors (such as IS) and to the validity of the so-called unable and unwilling-test. A closer analysis of the intervening States’ positions, however, instead reveals a gradual acceptance of the more expansionist interpretation of the legal framework first put forward by the United States as its “persistent advocate.” Moreover, the chapter addresses the degree of parliamentary involvement in decisions to deploy armed forces abroad. It observes how the present case seems to fit into a broader trend of increased parliamentary control over war-and-peace decisions on both sides of the Atlantic. Inasmuch as international legal arguments can and do play a role in parliamentary debates and concomitant resolutions, this trend carries the potential of contributing to the compliance pull of the jus ad bellum.