“It has become almost axiomatic that the great rights which are secured for all of us by the Bill of Rights are constantly tested and retested in the courts by the people who live in the bottom of society’s barrel.”

—Anthony Lewis, Gideon's Trumpet, 1964

One of the greatest challenges facing the criminal justice system is the need to balance the rights of accused criminals against society’s interest in imposing punishments on those convicted of crimes. This tension is illustrated by the debate over whether defendants have the right to be represented by an attorney.

Most Americans are familiar with the Miranda warning, which advises suspects of their rights that are guaranteed by the Fifth and Sixth Amendments: Criminal suspects have the right to refuse to answer questions from police; they have the right to an attorney; and if they cannot afford an...