This previous post notes Yale Law School Constitutional Law professor Jack Balkin‘s (of the popular Balkinization blog) article in which he favors the “living Constitution” approach over originalism as a theoretical framework for interpreting the U.S. Constitution.
In this recent blog post, Professor Balkin addresses a basic structure of constitutional interpretation and the limits of interpretive theory, and breaks down the topic into four basic issues: fidelity, interpretation, construction, and constraint. He then notes:

[T]he issue of what fidelity requires is not the same thing as the question of how the system produces constraint. That is to say, it’s possible (in fact it is likely) that the requirements of fidelity permit people to arrive at a wide range of different answers to constitutional questions over time, and that the work of constraining interpretation and construction is achieved by other features of the system. It is often assumed that what constrains judges are a set of rules of interpretation and construction, that, if followed, will produce correct answers that will also constrain judges, or, less ambitiously, keep judges from making arbitrary decisions (and poor decisions) or keep them from moving too far out of the mainstream of constitutional thought.
My view, by contrast, is that theories of constitutional interpretation, even the best theories, offer only part of the constraints necessary for the practice of judicial review, particularly when constitutional issues become most strongly contested. Rather, much of the work of constraint is produced by structural and institutional features of the constitutional system.

Check out the entire post.