What Movements Are and Are Not

Social movements are the organized form through which societies generate change that established interests cannot or will not. The most widely used working definition, from Sidney Tarrow's Power in Movement, treats a social movement as a sustained challenge to authorities or elites, mounted by people who share a common purpose and solidarity, through repeated contentious interactions with opponents (Tarrow 2011, pp. 7-9). Each element of this definition does analytical work: sustained distinguishes movements from momentary crowds; organized distinguishes them from spontaneous riots; challenge distinguishes them from interest groups with routine access; and contentious marks their characteristic use of disruption, performance, and claim-making outside regular institutional channels.

The distinctions matter because movements are often confused with adjacent phenomena. A crowd at a football match is not a movement. An interest group lobbying a ministry on behalf of its members is not, typically, a movement — it participates in routine politics. A revolution is movement-like but exceeds the category in scale and ambition, seeking to displace an entire regime rather than extract specific concessions from one. Tilly and Tarrow's Contentious Politics treats movements as one form within a broader family of contentious politics that also includes revolutions, civil wars, democratization episodes, and nationalist mobilization (Tilly and Tarrow 2015, pp. 6-11). Movements are the form specific to relatively open polities, where groups can organize publicly, make claims, and survive to mobilize again.

Movements make claims on behalf of broader interests than their immediate members. A neighborhood association opposing a specific development may be an interest group; an environmental movement opposing fossil-fuel expansion claims to speak for present and future generations. This broader claim is both rhetorical and structural: it shapes who joins, how the movement frames its grievances, and what counts as success. Movements without this broader claim-making tend to be reclassified as clubs, associations, or lobby groups.

They also operate through characteristic repertoires of contention — the historically available set of performances through which claims are made. Tilly documented how these repertoires changed in Britain between 1758 and 1834, shifting from localized, patronized, parochial forms (rough music, charivari, effigy burning) to the modern national-scale repertoire of marches, petitions, public meetings, rallies, and strikes that became standard in the nineteenth century and remains recognizable today (Tilly 1995, pp. 41-56). Contemporary movements have added occupations, flash mobs, digitally coordinated swarms, and online campaigns, but the core performances remain historically stable.

The scholarly study of these phenomena became a distinct subfield of sociology in the 1970s, drawing on earlier work in political science, history, and collective behavior. The standard synthesis is still Tarrow's Power in Movement, first published in 1994 and revised through multiple editions, which integrates the resource mobilization, political process, and framing traditions into a coherent account of how and when movements emerge, succeed, and decline (Tarrow 2011, pp. 13-18). The chapters that follow trace the theoretical lineage of this synthesis and the contemporary questions it has generated.