The purpose of this case study was to examine the effects of scaffolded instruction in the Toulmin Model of Argument on the problem solving strategies used by four sixth-grade writers while composing argumentative essays. Three major components of the Toulmin Model that were presented to participants were claims, data, and warrants. Participants for the proposed study were four sixth-grade students, two of whom were identified as "high ability" (one male and one female) and two of whom were identified as "average ability" (one male and one female). Results of the study were derived primarily from the analysis of intervention protocols and essays produced by participants. After completing a survey about their experiences with argument/persuasion, participating in a practice think aloud, and composing a pretest argumentative essay while providing a think aloud guided by the intervention protocol, participants received a total of six units of scaffolded instruction in the Toulmin Model over a period of four weeks. At the end of the instructional period, participants composed an "independent" argumentative essay under normal (non-protocol) conditions. For the posttest, participants provided a second think aloud guided by the intervention protocol while composing an argumentative essay. Pre-test, independent, and posttest prompts asked participants to formulate and support a claim about a proposed change to a school policy and were identical in form, audience, and task demands. As a result of the intervention instruction in the Toulmin model and the scaffolds I was able to construct through the intervention protocols, participants were able to move beyond knowledge telling to engage in knowledge transforming, moving back and forth between problem spaces of content and rhetoric, and thus more effectively handling the audience-related task demands of warranting claims and providing convincing supporting data - aspects of argumentative writing that existing research suggests pose the greatest difficulties for secondary students. I had hypothesized that the intervention instruction in the Toulmin model would also enable participants to more effectively handle the argumentative writing task demand of anticipating and responding to opposition, but this hypothesis was not supported by the study data.