Treaty FAQ

What is the oldest treaty still in force?

The Anglo-Portuguese alliance, set out in the treaty of 1373 and sealed by the Treaty of Windsor in 1386, is usually cited as the oldest alliance still in force. The Rush-Bagot Agreement of 1817, limiting warships on the Great Lakes, also remains in force between the US and Canada.

Can a treaty be canceled?

Yes. Withdrawal clauses allow exit with notice, like Article 50 for the EU. Material breach by the other party justifies suspension. Fundamental change of circumstances, rebus sic stantibus, rarely works. Simply breaking a treaty is possible but carries diplomatic and legal consequences.

What is the difference between a treaty and an executive agreement?

In the US, treaties require approval by two thirds of the Senate. Executive agreements need only presidential authority or simple congressional majorities. Most US international commitments today are executive agreements; formal Article II treaties are a small minority.

Why did Versailles fail while Westphalia lasted?

Westphalia exhausted all parties and included the losers in the settlement. Versailles dictated terms to a defeated but unoccupied Germany, which never accepted it as legitimate, and the victors did not enforce it. The difference between imposition and agreement, backed by enforcement, often determines whether peace treaties hold.

Are UN resolutions treaties?

No. Security Council resolutions under Chapter VII are binding decisions, a stronger enforcement mechanism than most treaties. General Assembly resolutions are recommendations without binding force. Only instruments meeting consent, ratification, and registration criteria become treaty law.

What was the shortest lived major treaty?

The Molotov-Ribbentrop Pact lasted under two years before Hitler invaded the USSR. The Treaty of San Stefano of March 1878 was replaced four months later by the Congress of Berlin. Brest-Litovsk lasted eight months before the Armistice of November 1918 annulled it.