The Judiciary in Democracy

In many democracies, the judiciary is protected, to one degree or another, from the voters.  Our federal judges, for example, though appointed by elected officials, then have lifetime tenure.  In more local venues, however, many judges are directly elected.  What is the role of the judiciary in a democracy, and how much protection from democratic processes is needed?  John and Ken probe the judiciary branch of government with Larry Kramer, Dean of the Stanford Law School, author of The People Themselves: Popular Constitutionalism and Judicial Review.