International law is generally considered to be a good thing. With important exceptions, such as Critical Legal Studies, scholarship in both International Relations (IR) and International Law (IL) reinforces this ‘nice law’ assumption and therefore overlooks or underestimates the law’s negative aspects. In contrast, this article assumes the power of international law to examine how international law can have effects that are unintended, unhelpful, or even perverse. In particular, I argue that international law distorts policy- and decision-making processes in liberal democracies by eroding personal responsibility and decreasing accountability; legal expertise and legal virtues crowd out important virtues of statecraft and prudence while shrinking our capacity for sophisticated moral and political thought; and an excessive focus on law can lead to suboptimal foreign policy outcomes. Rather than law being a bad thing per se, I examine the significant strategic and moral limits of international law. This raises the need to lower our expectations of international law, carefully examine the relationship between power and international law, and political responsibility and legal ethics, and more fully embrace our own personal responsibility. The article closes by suggesting a research programme on the dark sides of international law from various theoretical perspectives.