Education seeks to cultivate dispositions and skills that promote effective participation in democratic institutions, including the capacity to produce thoughtful written arguments about controversial issues. Unfortunately, students' argumentative writing is generally neither effective nor persuasive, and this is especially so for students with learning disabilities (LD). The most efficacious argumentative writing interventions explicitly teach strategies that can be used to self-regulate the writing process. These interventions reflect the "descriptive approach" to argumentation, which seeks to understand the influence of content and context on argumentative performance. A contrasting and complementary perspective, called the "normative approach," seeks to understand how critical standards can be ideally used to guide argumentation. The latter approach has received scant attention in instruction for students with LD. In this article, we first review studies in the LD literature that illustrate the descriptive approach to instructing argumentative writing, and then discuss how normative standards may be used to further promote the quality of students' written arguments. (Contains 2 figures and 1 table.)