Basdevant, Jules Keywords: Law on conclusion of international treaties | Mots clefs: Droit de conclure des traités | ABSTRACT Jules Basdevant shows that the practice of drafting diplomatic instruments other than treaties is uncertain, hesitant, and contradictory. The first part of his study deals with the conclusion and drafting of treaties: negotiation and signature, context, content drafting, ratification, recent practices and transformations (in 1926). The second part of the study deals with the drafting of dip…