The 10th Amendment was created to ease the fears of the Antifederalists that the Constitution’s list of enumerated powers was not sufficient to restrain the new federal government from encroaching on the legitimate powers of the states. Its subsequent influence on federal, state, and court actions is, however, debatable. When questions about the legitimate powers of the federal government are raised, they are rarely couched in 10th Amendment terms. Indeed, nearly everyone today would agree that it is a “truism” that whatever powers are not granted are reserved. But just how expansively or narrowly should those granted powers be interpreted? An excessively broad interpretation would effectively place no limits on federal authority at all. An excessively narrow interpretation would limit Congress only to those powers which were explicitly named in the enumerated powers—something James Madison argued would bring the exercise of any power to a standstill. The 10th Amendment, alas, provides no guidance for how to interpret the powers that were delegated.