Can a state 'unsign' a treaty?

Yes — under VCLT Article 18, a state can clearly indicate it no longer intends to become a party, releasing it from the non-defeat obligation.

What is the difference between ratification and accession?

Ratification follows signature; accession is for states that did not sign but want to join. The binding effect is the same.

Ratification | Model Diplomat

What It Means in Practice

Ratification is the formal act by which a state expresses its consent to be bound by a treaty after signature. It is the legal moment a treaty becomes binding on the state — not the signature, not the negotiation. Signature alone is preliminary: it indicates intent and obligates the state under Article 18 of the Vienna Convention on the (VCLT) not to defeat the treaty's object and purpose, but it creates no substantive obligations.

Ratification involves domestic processes that vary by state. In the US, ratification requires two-thirds Senate consent ("") under Article II of the Constitution — a high bar that has prevented US ratification of many treaties (CTBT, CEDAW, CRC, UNCLOS, others). In the UK, the executive ratifies after parliamentary scrutiny under the Constitutional Reform and Governance Act 2010. In many states, constitutional courts review treaties before ratification. France requires approval for treaties affecting fundamental .

How Ratification Works Mechanically

Once a state's domestic ratification process is complete, the state's instrument of ratification is deposited with the treaty's depositary — typically the UN Secretary-General, the government of the state where the treaty was signed, or an international organization designated in the treaty text. The deposit is the formal act that triggers the state's legal binding under the treaty.

Different treaties have different rules for when they enter into force. Most require a threshold number of ratifications (the required 50; the Rome Statute required 60; the required 55 covering at least 55% of global emissions). Once the threshold is met, the treaty enters into force for the states that have ratified it.

Ratification vs Signature

The signature-ratification gap can be substantial. Treaties are negotiated by executive officials and signed at the negotiating conclusion; ratification often requires lengthy domestic political processes that may never complete. Major examples:

The US signed but never ratified the CTBT (1996), the Rome Statute (2000, signature later 'unsigned'), CEDAW (1980), the ICESCR, the CRC.
Israel signed and then 'unsigned' the Rome Statute after its investigations of Palestine began.
Russia signed and then withdrew its signature from the Rome Statute in 2016.

The gap matters because signed-but-unratified treaties carry only the limited VCLT Article 18 obligation (not to defeat the treaty's object and purpose), not the full obligations of party states.

Reservations and Declarations

States can attach reservations or declarations to their ratification, modifying the legal effect of certain treaty provisions. The rules are governed by VCLT Articles 19–23 — a reservation is permitted unless prohibited by the treaty or incompatible with its object and purpose. See for the detailed .

Accession

States that did not participate in original treaty negotiation can join later through accession — the legal equivalent of ratification for non-original parties. Accession applies to most multilateral treaties and is the mechanism by which most states actually become parties to global treaties (since few states participate in the original drafting).

Common Misconceptions

Signature is sometimes assumed to bind a state. It does not, beyond the limited VCLT Article 18 'not to defeat object and purpose' obligation. Substantive treaty obligations attach only on ratification.

Another misconception is that ratification cannot be reversed. Many treaties include withdrawal provisions — the NPT allows withdrawal with 90 days' notice, the Rome Statute requires one year. States that ratify can sometimes leave; the legal framework for treaty exit is often as important as the framework for entry.

Real-World Examples

US Senate rejection of the (1919–20) is the historical paradigm of failed ratification — the US never joined the despite Wilson's leadership of the negotiation. The Comprehensive Nuclear Test Ban Treaty (CTBT) was signed by the US in 1996 but has never been ratified due to Senate opposition, leaving the treaty in legal limbo (it cannot enter into force until certain key states ratify). The Paris Agreement's rapid ratification in 2015–16 (entering force in less than a year) was unusually fast for a major multilateral treaty, reflecting the political momentum behind the agreement.

Ratification