What we usually think of as higher order skills in argumentation can be profitably viewed as systematic structures for organizing and representing information. Standard terms like “line of argument”, “synthesis”, “analysis” and “draft” can be viewed as ways of constructing, storing, and accessing data in a social context — data structures for social communication. What makes argument difficult are the multiple structures that arguers have to construct and negotiate when reading and composing. In this paper, we describe the WARRANT project, (...) a project designed to identify data structures of written argument and to design and implement computer tools to aid in the reading and design of argument. (shrink)