In this article, Betty Achinstein and Rodney Ogawa examine the experiences of two new teachers who resisted mandated "fidelity" to Open Court literacy instruction in California. These two case studies challenge the portrayal of teacher resistance as driven by psychological deficiency and propose instead that teachers engage in "principled resistance" informed by professional principles. They document that within prescriptive instructional programs and control-oriented educational policies, teachers have a limited ability to implement professional principles, including diversified instruction, high expectations, and creativity. In this environment, teachers who resist experience professional isolation and schools experience teacher attrition. Through these two cases, Achinstein and Ogawa express concern about the negative impact of educational reforms that are guided by technical and moralistic control. (Contains 4 endnotes.)