Provisional entry into force (sometimes "provisional application") is a device that lets states begin implementing a treaty—or designated parts of it—before all the formal steps of ratification, acceptance, or approval have been completed. It is governed primarily by Article 25 of the 1969 Vienna Convention on the Law of Treaties (VCLT), which permits provisional application where the treaty itself so provides or where the negotiating states have otherwise agreed.
The mechanism exists because multilateral treaties often require lengthy domestic ratification procedures, yet the underlying problem (trade barriers, arms flows, environmental damage) may demand earlier action. By applying a treaty provisionally, signatories accept its obligations on an interim basis, generating legal effects substantially equivalent to those of a treaty in force. Provisional application terminates if a state notifies the other parties of its intention not to become a party, unless the treaty or the parties agree otherwise.
Provisional application has been used in several prominent instruments:
- The General Agreement on Tariffs and Trade (GATT 1947) operated for nearly five decades under a Protocol of Provisional Application, never formally entering into force in the ordinary sense before being superseded by the WTO agreements in 1995.
- The Energy Charter Treaty (1994) was applied provisionally by signatories pending ratification; the Russian Federation's provisional application was a central issue in the Yukos arbitration awards.
- Parts of the EU–Canada Comprehensive Economic and Trade Agreement (CETA) have been provisionally applied since September 2017, covering matters within exclusive EU competence while national ratifications continue.
Provisional entry raises distinctive legal questions: the scope of obligations a state actually owes during the interim period, the relationship between provisional application and domestic constitutional requirements, and the consequences of unilateral termination. The International Law Commission adopted Guide to Provisional Application of Treaties in 2021, consolidating state practice and clarifying that provisionally applied obligations are, in principle, legally binding.
It is distinct from signature subject to ratification, which creates only the limited obligation under VCLT Article 18 not to defeat a treaty's object and purpose.
Example
Following Council approval, the EU and Canada began provisional application of most of the CETA trade agreement on 21 September 2017, pending ratification by EU member states.