Writing in 1970, Michael Lipsky (1970: 14) urged political analysts to direct their attention

Clearly Lipsky felt the answer to both questions was yes. He assumed that the ebb and flow of protest activity was a function of changes that left the broader political system more vulnerable or receptive to the demands of particular groups. Three years later Peter Eisinger (1973: 11) used the term “structure of political opportunities” to help account for variation in “riot behavior” in forty-three American cities. Consistent with Lipsky's view, Eisinger (1973: 25) found that “the incidence of protest is … related to the nature of a city's political opportunity structure,” which he defined as “the degree to which groups are likely to be able to gain access to power and to manipulate the political system.”

Within ten years the key premise informing the work of Lipsky and Eisinger had been appropriated as the central tenet in a new “political process” model of social movements. Proponents of the model (e.g., Jenkins and Perrow, 1977; McAdam, 1982; Tarrow, 1983; Tilly, 1978) saw the timing and fate of movements as largely dependent upon the opportunities afforded insurgents by the shifting institutional structure and ideological disposition of those in power.