Nico Krisch
Professor of International Law

In 1940, Hans Morgenthau — who had finished his postdoctoral work at the Graduate Institute just a few years earlier and was on his way to becoming a key post-war international relations theorist — advanced a grim vision of international law. For Morgenthau, “where there is neither community of interests nor balance of power, there is no international law”. This seemed utterly reductionist to many idealists of the interwar years who had hoped that international law would help to transform world politics — that it would help to realise "peace through law”. Morgenthau dismissed such hopes as a dangerous illusion, and in light of German aggression and the breakdown of the Versailles regime, his position struck a chord with many political observers.

This stance has had a deep impact on our thinking about the prospects of international law ever since. For realist scholars of international relations, there was not much to international law beyond the power play of the actors behind it. This changed somewhat when, in the 1980s, attention turned to international law’s role in overcoming collective action problems by stabilising international cooperation. The World Trade Organization’s (WTO) trade regime became a key example: here, international law helped states achieve welfare gains which all desired but could not achieve in the absence of stable rules and credible mechanisms for detecting non-compliance. Law’s role in this picture was more substantial than before, but it was still rather limited: changing international politics in a meaningful way was well beyond its purview.

For many international lawyers, especially in Europe, such realist and rationalist approaches failed to capture the full role of international law. Lawyers could not reconcile themselves to the idea that international law was merely a tool for governments, its use and acceptance subject to a constant recalculation of costs and benefits. For them, the impact of law and legality was deeper, and following international law was more often a matter of course rather than the result of rational calculus. Over the last fifteen years, as international law has expanded and interest in it has grown, some of these points have been vindicated, but some severe limitations on international law’s effects have become clearer, too.

One part of the new picture of international law is its increasing routinisation. As international law has come to cover more and more issue areas, ranging from trade to food safety, environmental protection and the laws of war, governments have established dedicated bureaucracies which often take international rules for granted. This helps to stabilise international law in the face of shifts in political interests and attitudes. But this stabilisation only goes so far: when the stakes are high, legalised routines may be disrupted and compliance again becomes subject to a more direct calculation.

International law’s increasing reach into issues of domestic politics has also brought new players to prominence. In countries with independent judiciaries, domestic courts have turned into key players in the implementation of international law, and they have also become important focal points for social mobilisation, as for example in the area of human rights. Where international rules connect with social, political and judicial actors at the domestic level, they can foster political change and embed themselves more durably in the fabric of national law. Yet the deeper impact of international law in the domestic sphere can also cut the other way. When international law is seen as too intrusive, it becomes politicised, potentially provoking a hostile response. The current challenges, in Switzerland and elsewhere, against the European Court of Human Rights and those in Latin American countries against international investment arbitration, are cases in point.

Yet international law has also been found to have a more broadly transformative effect. On issues such as the general prohibition on the use of force, the range of admissible weapons in war, or the prosecution of international crimes, it has helped to redefine standards of acceptable behaviour, thus altering the realm of possible political action and the costs associated with deviance. Such change has not happened quickly or by itself: it had to rely on active social and political support. In the dynamics of change in international politics, international law may help to crystallise and stabilise normative expectations, but it will always be only one piece among others.

As world politics become increasingly "legalised” and ”judicialised”, our picture of the effects of international law has also changed. It is far more multi-faceted today than it was for Morgenthau at the outset of World War II — we no longer see international law as merely a reflection of common interests or power relations, but also as a force that can help to alter the political landscape in manifold ways. But we have not gone back to the idealist picture of earlier times either. Whatever international law can achieve depends on whether it aligns with social and political constellations, both at the international and the domestic level. These constellations will often impose narrow limits on political change, and if international law is not attuned to such limits, it runs the risk of overreaching — and of either remaining a pipe dream or, worse, triggering a significant backlash.

This article was published in Globe, the Graduate Institute Review.