Since then, the basic idea of collective action and forward progress has taken such a dizzying variety of forms — liberal and conservative, grass-roots and top-down, “poor people’s movements” and “rich people’s movements” — that scholars have a hard time settling on a single meaning for what a social movement is and does. “The term has multiple definitions,” write the editors of the Encyclopedia of American Social Movements, “but perhaps the simplest one is the best: the coming together of large