In lively prose, Professors Ackerman and Ginsberg explain the origins of each constitutional provision, assess the ways in which each has been used and interpreted over time, and examine the controversies that continue to surround key constitutional principles such as the president's powers to regulate interstate commerce. The authors also address a number of long-standing American political principles and practices that are not discussed in the Constitution, though many Americans think they are. A selection of related documents is included, as well as a list of recommended online resources for further reading and research. The Second Edition includes expanded headnotes, coverage of recent Supreme Court decisions, and other important updates.