This article tackles the question: given that ethnic movements in democracies often exhibit similar grievances and claims, what explains variations in their patterns of ethnic mobilization? Specifically, why do some ethnic movements turn to violence while others remain non-violent, and why do some demonstrate relative sustainability over long historic periods while others experience temporary flare-ups followed by long periods of demobilization? Utilizing new research in contentious politics, this study advances a dynamic approach to the examination of ethnic mobilization, arguing that variations in mobilization patterns are best analyzed according to the extent of a movement's institutionalization. Illustrating the utility of this analytical framework with an in-depth analysis of the case of the Francophone Québécois, this article develops the concept of a spectrum of institutional ethnonationalism in order to explain diverse mobilization patterns.