Excerpt from Justice O'Connor's concurring opinion in McCreary County v. ACLU (2005):

At a time when we see around the world the violent consequences of the assumption of religious authority by government, Americans may count themselves fortunate: Our regard for constitutional boundaries has protected us from similar travails, while allowing private religious exercise to flourish. The well-known statement that “[w]e are a religious people,” has proved true. Americans attend their places of worship more often than do citizens of other developed nations and describe religion as playing an especially important role in their lives. Those who would renegotiate the boundaries between church and state must therefore answer a difficult question: Why would we trade a system that has served us so well for one that has served others so poorly?