This essay begins in anxiety. My own but also others’, or at least what I take to be their anxiety. I will come to mine by way of theirs which, in my surmise, is about the potential of protest to bring about social disorder and change. Consider the nineteenth-century French social psychologist and sociologist Gustave Le Bon, for example. In his famous book The Crowd: A Study of the Popular Mind (1895/1960), Le Bon reveals his deep concern about the growing power of “the masses” (p. 16). Influenced by his knowledge of the French Revolution and likely even more by the social upheavals of his own day, Le Bon is convinced that the masses are determined “to destroy utterly society as it now exists” (p. 16). Although he notes that crowds can be virtuous and heroic (p. 19), his overriding concern was their negative qualities, especially with regard to one variant of the “crowd,” mass movements. Crowds, he asserts, “are only powerful for destruction” (p. 18); they display “extreme mental inferiority” as well as an “incapacity to reason, the absence of judgment and of the critical spirit,” and an “exaggeration of the sentiments” (pp. 4, 35-36). The crowd, Le Bon asserts, is “the slave of . . . impulses” and “guided almost exclusively by unconscious motives” and instincts: “its acts are far more under the influence of the spinal cord than of the brain” (p. 36). He sounds anxious. I mention Le Bon because, as a sociologist who studies social movements, my own intellectual lineage goes back to him, if mostly ashamedly, and indeed is still haunted by his psychological theory of mass political action, which reduces contentious politics to the instinctdriven, unconscious, irrational, and destructive behavior of unruly mobs.2