Federalism, State Sovereignty, and the Constitution: Basis and Limits of Congressional Power [September 23, 2013] [open pdf - 349KB]
"The lines of authority between states and the federal government are, to a significant extent, defined by the United States Constitution and relevant case law. In recent years, however, the Supreme Court has decided a number of cases that would seem to reevaluate this historical relationship. This report discusses state and federal legislative power generally, focusing on a number of these 'federalism' cases. The report does not, however, address the larger policy issue of when it is appropriate--as opposed to constitutionally permissible--to exercise federal powers."
CRS Report for Congress, RL30315
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html