The Economics of Treaty Ratification

In this paper we study the strengths and weaknesses of the matching-reservations mechanism introduced by Article 21 of the Vienna Convention. When states face asymmetric incentives, the rules introduced by the Vienna Convention may not discourage all reservations. We also analyze the welfare properties of the matching-reservations outcomes generated by Article 21 when such asymmetric incentives are at work. We show that Article 21 provides quite an effective solution to the prisoner's dilemma problem, but does not always induce socially optimal levels of ratification. A social optimum will be achieved under Article 21 only in the limited subset of cases where signatory states have homogeneous payoff functions, or when all states prefer full ratification, despite the differences in the incentives that they face.