How many letters does the top answer for “a written agreement between two states or sovereigns” have?

The most common answer is pact (4 letters).

Crossword clue: a written agreement between two states or sovereigns

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

pact 4 letters wn-def

a written agreement between two states or sovereigns

treaty 6 letters wn-def

a written agreement between two states or sovereigns