Popular commentaries suggest that the movement against genetic engineering in agriculture (anti-GE movement) was born in Europe, rooted in European cultural approaches to food, and sparked by recent food-safety scares such as "mad cow" disease. Yet few realize that the anti-GE movement's origins date back thirty years, that opposition to agricultural biotechnology emerged with the technology itself, and that the movement originated in the United States rather than Europe. We argue here that neither the explosion of the GE food issue in the late 1990s nor the concomitant expansion of the movement can be understood without recognizing the importance of the intellectual work carried out by a "critical community" of activists during the two-decade-long period prior to the 1990s. We show how these early critics forged an oppositional ideology and concrete set of grievances upon which a movement could later be built. Our analysis advances social movement theory by establishing the importance of the intellectual work that activists engage in during the "proto-mobilizational" phase of collective action, and by identifying the cognitive and social processes by which activists develop a critical, analytical framework. Our elaboration of four specific dimensions of idea/ideology formation pushes the literature toward a more complete understanding of the role of ideas and idea-makers in social movements, and suggests a process of grievance construction that is more "organic" than strategic (pace the framing literature).