We're joined by Michigan law professor Richard Primus to talk about his new book, "The Oldest Constitutional Question: Enumerated and Federal Power." Richard describes one of the the most widespread beliefs about constitutional law -- that the federal government is one of limited, enumerated powers -- and why he thinks it is actually wrong. Along the way, we discuss methods of constitutional interpretation, the relationship between the official story of the law and legal practice, and wrestle with the surprisingly hard question of how many congressional powers are listed in the Constitution.