The USA and European countries have developed radically different approaches to regulating racist hate speech over the past 50 years. This divergence is largely a function of rulings by the US Supreme Court and the European Court of Human Rights. While the Supreme Court has elected to uphold the freedom to express inflammatory racism in public, the European Court has almost always sided with its 47 member states when they have enforced laws curbing racist hate speech. Although a number of scholars have described the differences between the USA and Europe, there is currently no theoretically informed explanation of this important divergence. In this article, I draw on scholarship about comparative law and freedom of expression to develop and test hypotheses about judicial regulation of racist speech in the USA and Europe. I argue that political cultural variables, legal texts and differences in jurisprudential norms strongly influence the overarching patterns of outcomes we see across jurisdictions. Yet, preferences of individual judges also matter, especially in cases that have shifted the trajectory over time within a region, or that have cut against the grain of the predicted pattern. I examine the course of hate speech regulation in the USA and in Europe, illustrating how the variables identified in the model affected court decisions in each region and reviewing specific cases that constituted turning points in the regulation of racist speech.