UnknownRussia’s military intervention in Ukraine naturally prompted a lot talk about the limits of international law. Eric Posner noted: “ 1. Russia’s military intervention in Ukraine violates international law. 2. No one is going to do anything about it.” Julian Ku argued: “International law can be, and often is, a very important tool for facilitating international and transnational cooperation. But it is not doing much to resolve to Ukraine crisis, and international lawyers need to admit that.” For Ku, the current crisis supports the claims of Rationalist law-skeptics, international law works when legal requirements align with self-interest. Many others, including a good portion of my students see the failure of international law in Ukraine.

Russia’s  intervention is indeed a serious blow to international law. Yet mere breach does not mean international law is epiphenomenal. The international community has condemned Russia’s action. Sanctions from the U.S. are already in effect. G7 suspended preparations for the G8 meeting in Russia. Eurozone countries seem committed to isolating Russia if a diplomatic solution cannot be found promptly even though they-especially Germany- are particularly dependent on Russia for gas and oil. All this indicates that international law is consequential. Eric Posner’s first point is correct. Russia’s intervention violates international law. But his second point seems rash. Many are doing something about it.

We would be remiss if we merely see international law as a constraint on state behavior. Limiting the scope of state action is one of law’s several functions. And in that regard, the law has failed. Yet international law also works through other channels. It shapes social expectations of appropriate behavior, mobilizes domestic and international civil society actors, imposes reputational and material costs on violators, allows for naming and shaming, and creates a discourse centered on legality and legitimacy. Russia’s intervention is a profound challenge to international law, but we should not despair. International law still matters. Peter Spiro, Chris Borgen, and Erik Voeten seem to agree.