I recommend Irma Brandeis' superb (& brief) study of the Divine Comedy, titled Ladder of Vision. See her treatment of the "Farinata" episode from Inferno, for light on Dante's presentation of partisan factionalism and its moral effects.

Brandeis, in persona, was the model for the "Clizia" figure in Montale's "dantesque" poetry (30 years before her study was published). Montale achieved, for the Italian language, the "classic" as I've been trying to describe it.