When you break a municipal law, the local police come to arrest you. But what happens when you break international law? It’s no secret that laws and their enforcement are the result of politics. Unlike traditional law, which passed down by governments, international law is passed up by governments by consensus. It’s up to individual governments to hold themselves to those laws or more powerful countries to exert pressure towards enforcement.

Naturally, this means that international law is as much about power as it is about justice. Whenever a powerful country breaks an international treaty — the basis of international law — they make a legal argument that legitimize their over-reach of power. When they win a case before an international court, it often empowers states to use certain technologies or tactics that international law doesn’t adequately address.

Ian Hurd is the director of Northwestern University’s International Studies Department. In his new book, How to Do Things with International Law, Hurd looks at how recent legal justification for war, torture, and drones only provide cover for the most powerful countries. Hurd joins Worldview to discuss how powerful governments abuse international law for foreign policy gain.