Crisis in the laws of war? Beyond compliance and effectiveness

How can we tell what state the laws of war are in today, and whether they face exceptional pressures? Standard accounts of the condition of this body of law focus on problems of compliance and effectiveness. In particular, there is a dominant international legal diagnosis that most non-compliance is accounted for by the prevalence of non-state belligerents in irregular or asymmetric conflicts. We propose that any such diagnosis is partial at best. A focus on compliance and effectiveness tells us nothing about the reasons for actor behaviour, or about its impact on the regime. We advance a different conceptual framework, exploring the complex connections between compliance, effectiveness and legitimacy. We propose an alternative diagnostic model that places legitimacy at the heart of the analysis, treating it as causal, not simply symptomatic. This highlights when violations result in legitimacy costs for the individual actor, as opposed to reaching a tipping point when violations cumulatively impose legitimacy costs on the regime itself. We argue for the need to move beyond discussions framed by compliance and effectiveness, and towards the forms, reasons and reception of non-compliant behaviour, as this provides a truly social measure of the state of the law. In order to illustrate this, we examine three distinct types of challengers — Islamic State of Iraq and the Levant, the US and Russia — and present them as, respectively, revisionist, rejectionist and denialist threats to the regime. Unusually, the laws of war today face challenges on all three fronts simultaneously