Such a multi-faceted analysis cannot be conflated into two dimensions. Whatever the allure of absolute doctrines, it is just too simple to declare expression "protected" or "unprotected" or to proclaim a regulation "content-based" or "content-neutral." John Paul Stevens (1992)
American legal doctrine evolved from a formalistic categorical approach that dominated legal thinking during the nineteenth century to a realistic balancing approach that developed over the course of the twentieth century. A similar process is now occurring in the constitutional doctrine governing freedom of expression-a process that may culminate in the adoption of what United States Supreme Court Justice John Paul Stevens calls a "constitutional calculus."
Indiana Law Journal
Wilson R. Huhn, Assessing the Constitutionality of Laws that are Both Content Based and Content Neutral, 79 Indiana Law Journal 801 (2004).