In thirteenth-century French debate songs, known as jeux-partis, poets frequently dwell on the divided nature of their songs. The poetry of a jeu-parti is divided by a dilemma question, which is debated by two trouvères. Division can also be seen in the tonal structure of jeu-parti melodies. This paper presents the findings of a systematic survey of normative melodic practice in the jeu-parti. Drawing on Hepokoski and Darcy’s influential concept of norms and deformations (2006) and debates on tonal norms in fourteenth-century song, I suggest what the tonal norms of the jeu-parti might have been. I also consider the problems of applying the model of norms and deformations to a corpus whose melodies can be agonistically and, on occasion, violently divided.