Abstract
This paper borrows the concept of “case” from academic debate and the concept of evolution from negotiation to analyze case arguments that evolve during a 10-hour teachers' bargaining. The paper adopts a developmental model of case based on bargaining interaction. Transcripts of the sessions are analyzed by plotting the argumentative clash, by identifying case types, and by determining patterns of case development. The study reveals that case type changes through offering counterproposals, clashing on issues, and shifting arguments for and against a proposal. Moreover, patterns of case development indicate which issues are resolved through problem solving as opposed to compromises and which ones emerge as salient or become dropped in the negotiation.