In an increasingly complex and interdependent world, states resort to a bewildering array of regulatory agreements to deal with problems as disparate as climate change, nuclear proliferation, international trade, satellite communications, species destruction, and intellectual property. In such a system, there must be some means of ensuring reasonably reliable performance of treaty obligations. The standard approach to this problem, by academics and politicians alike, is a search for treaties with "teeth"--military or economic sanctions to deter and punish violation.

The New...