Abstract

War and peace is a dichotomy that reflects humans’ desire to classify complex situations into simple and understandable concepts. Yet reality is more nuanced than the dichotomy suggests. This raises the question whether definitions of war and peace can inform a better understanding of modern competition, confrontation, and conflict – in particular of hybrid warfare and grey-zone conflict. While no common or widely accepted definitions of war and peace exist in the literature, how international law treats the divide between war and peace allows us to assess how states have jointly conceptualized and continue to perceive war and peace in international relations.

Accordingly, this chapter inquires how international law treats the divide between war and peace by tracing and analyzing the relevant legal rules of jus ad bellum and jus in bello. Thereby, the chapter clarifies the divide’s meaning commonly agreed by states and related behavior. It also offers insights into respective legal challenges that are particularly relevant to hybrid threats, hybrid warfare, and grey-zone conflict. The chapter finds that international law has evolved such to encapsulate war with different labels and legal concepts: war is prohibited under the banner of use of force; war is fought in the name of international peace and security when authorized by the UN Security Council; war tends to be justified as self-defense; and the existence of war is determined by relatively aleatory application of international humanitarian law (IHL).

Hence, the chapter argues that due to its conceptualization and evolution, modern international law does not offer much clarity on the divide between war and peace. Rather, international law confuses the boundaries and conflates the concepts – implying certain parallels to what George Orwell had termed ‘war is peace’ – to the extent that there is a relatively broad legal grey zone on the two notions. This results in analytical difficulties but also a certain normative permissibility, which is particularly relevant in the context of hybrid threats, hybrid warfare, and grey-zone conflict. The chapter concludes by identifying normative implications for the future of peace and war.