It is this depiction of international law that often culminated in the question of whether international law was really law. How could international legal norms be effective if their validity depended on the will of states, the very subjects international law should govern? This doubt in the validity and effectiveness of international law ultimately led to a rupture between the two disciplines of international law and international relations theory after the Second World War. Two scholars, Edward Hallett Carr and Hans Morgenthau, suggested around this time that international law was particularly inept for understanding the behaviour of nations. They were disappointed by what they identified as an idealistic belief in international law which, after all, had not prevented – for the second time – a world war. They proposed instead a more ‘realistic’ assessment of international relations based on power and interest. The founding realist school of international relations theory thus questioned the effectiveness and relevance of international law as a decisive influencing factor for the behaviour of states and for the assurance of international peace and security.
Much has changed since then. The international legal order has diversified in every possible way. There are countless bilateral and multilateral contracts between states (called treaties or conventions in international law), and more than 5,000 intergovernmental organisations and their different organs engage in the regulation and administration of nearly all aspects of international life.
International legal norms pervade global affairs. Every time you travel internationally, send an email, or update your social media profiles, there are not only domestic but supranational legal norms at play, including regional norms as in the European Union. Be it border control, diplomatic and consular relations between countries, the determination of flight and navigation routes, internet regulation, privacy, the use of postal and telecommunication services, industrial standards or cross-border environmental hazards – international law permeates these areas as much as the better-known fields of the protection of human rights, humanitarian interventions and the fight against transnational terrorism.
It is important to understand, then, that the question of whether and how international law matters depends not least on one’s conceptual outlook on international life. This chapter introduces you foremost to the (traditional ‘occidental’ or ‘Western’) normative understanding of international law in order to show you how international lawyers think and how they use international law. This implies a focus on valid legal rules that authoritatively regulate international life. Yet the understanding of international law as a system of legal norms is not the only possible approach, nor is it the solely valid one. In fact, there are numerous other approaches that complement the normative outlook on global law (Walker 2014). It is also important that the occidental depiction of international law is not the only one existing in the world. Scholars from outside the West have shown, for example, how the dominant view of international law neglects important and often earlier contributions to international law by other cultures. Asian, African and Latin American countries should form part of our understanding of international law. For example, international treaties existed already in Africa and Asia over three thousand years ago. Islamic legal thought, present in Persia, India, South Asia and Europe, also had legal regulations of how to conduct hostilities at least since the seventh century. There is not one single conception of international law or international politics.
By focusing on the normative understanding of international law, the chapter takes a modest approach and steers a middle ground. There are also conceptualisations that portray international law as a cosmopolitan order securing solidarity and peace in a ‘post-Westphalian’ world in which states have largely lost their status as sole sovereigns. On the other hand, there are theories that continue to question the social effectiveness and relevance of international legal norms to shape the behaviour of international actors. In addition, one can also analyse international law through empirical research that uses collected data about the social behaviour of actors as it is done, for example, to scrutinise the effectiveness of human rights norms. Yet, a purely empirical analysis has difficulty in conveying the idiosyncrasy of normative thinking and argumentation in international law. Even if collected data shows instances of non-compliance with human rights norms, it would be wrong to draw conclusions from this about the binding character or range of social effects of these norms.
International lawyers as a particular group of professionals learn techniques to determine which legal norms exist and which are applicable to the relevant actors in a certain situation. Lawyers speak of the sources and subjects of law. They learn how to apply these norms using specific techniques, such as interpretation or the balancing of conflicting rights. These professional techniques are not value-neutral or objective but involve subjective choices and politics. An approximation to objectivity and ideals of justice is achieved only through specific procedures that need to be followed, recognised modes of argumentation and particular processes of decision-making. In a nutshell, international law consists of certain conventions on argumentation and modes of conflict resolution that some regard as a craft, others as an art. Most likely it is both.