In this article, I first briefly describe the U.S. Supreme Court’s decades-long process of incorporating the federal Bill of Rights against the states. Second, I argue that incorporation of the Bill of Rights has come with significant costs to federalism in the United States. Third, I suggest that the American experience provides a cautionary note for the European Union as it grapples with the question of whether and to what extent to apply the Charter of Fundamental Rights to its constituent nations. I end by identifying options available to the European Union to avoid at least some of this harm to federalism while, at the same time, securing some of the benefit that might be occasioned by incorporating the Charter.