The federal system of the United States is based on the bedrock premise that the states bear the primary responsibility for criminal justice policy. States are better able to ensure that local communities can define crimes and set sentences according to the preferences of their residents. Indeed, it has long been recognized that criminal justice is at the core of state, not national, responsibility.
In recent decades, however, the importance of federalism has often been overshadowed by shortsighted political concerns. In particular, there has been an unprecedented expansion of federal criminal law into areas traditionally left to the states. The federal government has intervened in many local crimes--from carjacking to crimes committed with a firearm or involving drugs--without any showing that federal intervention is necessary or appropriate. While there are important areas that require federal intervention, many federal crimes of the past few decades fall outside this category...