Petitions, picket lines, civil disobedience--this kind of political mobilization required a certain shift in vision. "For a protest movement to arise out of [the] traumas of daily life," the sociologists Frances Fox Piven and Richard Cloward have observed, "the social arrangements that are ordinarily perceived as just and immutable must come to seem both unjust and mutable." This usually happened during extraordinary times, when large-scale social transformations or economics disturbances--the postwar housing shortage, say--profoundly upset the status quo. But it was not simply enough to perceive injustice. Mass resistance was possible only when people believed they had the collective capacity to change things. For poor people, this required identifying with the oppressed, and counting yourself among them--which was something most trailer park residents were absolutely unwilling to do.