This is the second edition of Professor Tushnet's short critical introduction to the history and current meaning of the United States' Constitution. It is organised around wo themes: first, the US Constitution is old, short, and difficult to amend. Second, the Constitution creates a structure of political opportunities that allows political actors, icluding political parties, to pursue the preferred policy goals even to the point of altering the very structure of politics. Deploying these themes to examine the structure f the national government, federalism, judicial review, and individual rights, the book provides basic information about, and deeper insights into, the way he US constitutional system has developed and what it means today.