Provisional Application of Treaty

The provisional application of a treaty, or of part of a treaty, is a mechanism available to States and international organizations to give effect to all or some of the provisions of a treaty pending entry into force. The possibility and the principles governing provisional application are addressed in Article 25 of the Vienna Convention on the Law of Treaties¹ and Article 25 of the Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations. Although both provisions are of central importance for provisional application, they do “not necessarily reflect all aspects of contemporary practice on the provisional application of treaties”.² 

The International Law Commission included the topic of “Provisional Application of Treaties” in its programme of work in 2012. In 2018, the International Law Commission adopted its Draft Guide to Provisional Application, containing 12 Draft Guidelines and commentaries thereto, in first reading.³ The Draft Guide is aimed at providing “assistance to States, international organizations and other users concerning the law and practice on the provisional application of treaties” and at directing “States, international organizations and other users to answers that are consistent with existing rules and most appropriate for contemporary practice”.⁴

Provisional application of a treaty is optional. It needs the agreement of the States or international organisations concerned.⁵ Such agreement can be included in the treaty itself, or provided in any other manner. States and international organisations can also agree on other conditions, like the conformity of provisional application with internal law, or provide for specific opting out mechanisms. Article 45 of the Energy Charter Treaty contains such further conditions that gave rise to difficulties in the Yukos cases.⁶

It is well established that the provisional application of a treaty can be based on a provision in the treaty in question. Article 25(1)(a) of the Vienna Conventions on the Law of Treaties codifies this possibility. The Draft Guide to Provisional Application also accepts this legal basis.⁷ Some bilateral investment instruments include provisions for provisional application (or provisional entry into force).⁸ Article 45(1) of the Energy Charter Treaty contains an agreement between all signatory parties to apply the provisions of the Energy Charter Treaty provisionally under some conditions.⁹ Other multilateral or plurilateral investment instruments also contain provisions on provisional application.¹⁰

States or international organisations concerned can also agree to apply a treaty provisionally in a separate treaty or through any other means of arrangement. Article 25(1)(b) of the Vienna Conventions on the Law of Treaties acknowledges this.¹¹ The International Law Commission has endorsed a similar view.¹² Some treaties specifically provide for the possibility to agree, separately, on provisional application¹³ or to make declarations to that effect.¹⁴ But even if the treaty does not contain any provision concerning its provisional application, States have agreed to apply the provisions of the treaty on a provisional basis and pending entry into force, for instance, through exchange of notes,¹⁵ or through unilateral declarations accepted by the other relevant party.¹⁶ The form of the agreement is less significant than the intention of the States or international organisations concerned.¹⁷ 

Unless the treaty provides otherwise, its provisional application creates legally binding obligations and rights to apply the treaty as if it was already in force.¹⁸ The violation of the provisions of the treaty applied provisionally may entail international responsibility in the same way as if the treaty was in force.¹⁹ This has been accepted by decisions of arbitral tribunals.²⁰

Provisional application ends if the treaty enters into force.²¹ Tribunals have considered that the entry into force of a treaty in respect of some territories does not necessarily entail the termination of provisional application of the same treaty in respect of other territories, to which the treaty continues to apply on a provisional basis.²² Unless the treaty provides or the States and international organisations concerned have agreed otherwise,²³ provisional application can also be terminated through a notification of the State or the international organisation concerned that it does not intend to become a party to the treaty.²⁴ Some investment instruments contain provisions that extend the protection of investors and investments in case of the termination of provisional application (Sunset clauses).²⁵