Federalism—including its meanings and limits—remains one of the most contested principles in constitutional law. To fully understand its importance, we must turn to a landmark decision nearly two centuries old. M’Culloch v. Maryland (1819) is widely regarded as the Supreme Court’s most important and influential decision—one that essentially defined the nature and scope of federal authority and its relationship to the states. Mark Killenbeck’s sharply insightful study helps us understand wh...

In the wake of the 2000 Election, the relationship between the Supreme Court and the American states has become more important. Once derided by the Court as a 'truism,' the Tenth Amendment has in recent years been transformed from a neglected provision into a vital 'first principle.' As such, it has provided the foundation for a series of decisions in which the Supreme Court has elevated the status of the states, often at the expense of federal power and in the face of previously settled a...