The Provisional Application of Arms Control Treaties

This article examines a development that emerged in the 1990s whereby parts of arms control treaties are applied provisionally pending the definitive entry into force of the instrument concerned, as foreseen in article 25 of the 1969 Vienna Convention on the Law of Treaties. Following a brief introduction to the technique of provisional application, an overview is provided of entry into force clauses of arms control treaties, whose principal requirement is ratification by some or even all signatories. The role of provisional application in the law of arms control is then considered in the light of the inherent sensitivity of the interim period between the conclusion and entry into force of arms control treaties. Various instances of provisional application are described with a view to clarifying the features of each provisional regime. The treaties concerned are the Treaty on Conventional Armed Forces in Europe, the Treaty on Open Skies, the Treaty on Further Reduction and Limitation of Strategic Offensive Arms (START II), the Ottawa Convention on the Prohibition of Anti-Personnel Mines, the Chemical Weapons Convention, the Comprehensive Nuclear-Test-Ban Treaty (CTBT) and certain subsidiary arms control agreements. The related question of the international legal status of the preparatory commissions that preside over the provisional implementation of certain arms control treaties establishing new international organisations is also considered. Among the conclusions reached are that the provisional application of an arms control treaty may be a valuable confidence-building mechanism and that in certain situations the technique may contribute to the emergence of a new norm of customary international law.