The all-states formula is one of three standard participation clauses used in multilateral treaties deposited with the UN Secretary-General, alongside the Vienna formula (limited to UN members, specialized agency members, ICJ Statute parties, and states invited by the General Assembly) and the any-state formula. Under the all-states formula, a treaty is open to participation by "all States," without requiring prior recognition by other parties or UN membership.
The formula emerged in the 1960s and 1970s to resolve a recurring problem: divided or contested states (e.g., the two Germanys, the two Koreas, North and South Vietnam) were excluded from key conventions because depositaries could not determine whether they qualified as "states." The General Assembly addressed this through guidance to the Secretary-General, notably in the context of the Vienna Convention on the Law of Treaties (1969). When acting as depositary, the Secretary-General follows the practice that he will be guided by Assembly decisions on whether an entity falls within the "all states" category, often referred to as the "Vienna all states formula" understanding.
In practice, the Secretary-General defers contested cases to the General Assembly rather than independently determining statehood. This depoliticizes the depositary function but means participation can still be blocked politically. The formula appears in major instruments such as the Vienna Convention on Diplomatic Relations (1961), the NPT (1968), and the Vienna Convention on the Law of Treaties (1969).
For practitioners, the formula matters because it determines who may sign, ratify, or accede, and therefore who counts toward entry-into-force thresholds. It is distinct from voting rights or recognition: deposit of an instrument under an all-states clause does not imply recognition by other states parties, a point routinely reiterated through reservation or declaration.
Example
When the Cook Islands deposited its instrument of accession to several UN conventions, the Secretary-General relied on the all-states formula and prior General Assembly practice to accept it as a participating state.