Americans commonly believe that their country is unique in its commitment to the separation of church and state. Yet by the European measure, the American separation of church and state looks strikingly weak, since Americans permit religious rhetoric to permeate their politics and even cite the Bible in court. In light of these striking differences, this article argues that it is wrong to imagine that there is some single correct measure of the separation of church and state. Instead, northern continental Europe and the United States have evolved two different patterns, whose historical roots reach back into the Middle Ages. In northern continental Europe, unlike the United States, historic church functions have been absorbed by the state. The consequences of this historic divergence extend beyond familiar questions of the freedom of religious expression, touching on matters as diverse as welfare policy and criminal law.