Whatever the source of contentious claims, it is political opportunities and constraints that translate them into action. They produce social movements by accessing known and flexible repertoires of contention; by developing collective action frames and collective identities; and by building mobilizing structures around social networks and organizations. While the opportunities and constraints in their environments give challengers incentives to mobilize, it is their cultural, organizational, and practical resources that are the foundations for social movements.

But three things are missing from this two-stage image of contention and movement formation. First, it deals with social movements as if they emerged, made claims, and evolved all on their own. Second, it ignores the fact that the shifting of opporrunities and constraints does not cease with the triggering of collective action. Third, it leaves out authorities, who do not sit idly by as challengers contest their rule: they respond weakly or strongly, selectively or generally, intelligently or stupidly to the emergence of contention, setting a pattern of interaction that affects other challengers too.

These additional factors establish broader waves of contention than the individual movements that have filled most academic treatments of contentious politics. In combination, they determine whether a burst of contention will sputter out like a roman candle or ripen into a cycle of contention – or even a revolution. It is to understanding when and how contention broadens into general cycles that this chapter is devoted.