Again, this is me posting on Adam Levitin's behalf because he is away from Internet access as he owns an Apple computer (often a redundant statement). Adam writes:

R.
Glenn Hubbard and Tim Kane have an op-Ed in the NYTimes proposing a federal
balanced budget amendment as the solution to federal deficits. 

I've got two
gripes about this "solution", both of which may reflect the
limitations on economists as policy makers. First, do we really need yet
another neat little legal solution for a non-legal problem? Unless
process is the goal, law isn't likely to solve political problems. Perhaps I've been reading too much on Chapter 9 and ideas for adapting
that chapter (which should probably be repealed from the Bankruptcy Code) to
situations where it is even less appropriate. Law isn't going to fix
government debt problems. Those are political problems that need
political fixes. The political system won't abide by a legal regime it
doesn't want.  

Second,
if Hubbard and Kane had looked at the literature on state balanced budget
amendments, they'd have learned that they are often warped by judicial
interpretation, disregarded, or result in all sorts of budgetary contortionism. They're not a solution. Simply put, there's no way to force a
self-commitment device on the Leviathan.  Government will be bound only if
it wants to be bound. 

At the risk of hijacking Adam's point, I'd make a similar observation about constitutional or legal commitments to protect governmental obligations such as promises not to violate public pensions. These are ultimately political issues.