Grumbach, M. (2026). The fortunes of radicalization: How the party environment determined the fate of radical movements in the late 20th-century United States. Critical Sociology, 0(0).

Radicalization during the 1960s and 1970s is often cited as a cause in the decline of American New Left movements, but right-wing movements also radicalized during this period and did not suffer the same consequences. This comparative-historical study traces the trajectories of four sectarian radicals who led conservative Christian and ultra-left movements that emerged in the United States in 1965. Bridging social movement literature with Gramscian theory, I argue that the variation in the fortunes of radicalization stems from the divergence between the formal party blocs. Radicalization on the left resulted in isolation and implosion because the Democratic Party bloc lacked resources and its interest-group configuration was inhospitable to radicalism. On the right, the Republican Party bloc was in an ascendant phase of organizational growth and fused the hitherto dispersed ideological currents of social conservatism and market fundamentalism. The availability of resources in tandem with the hegemonic configuration of the Republican Party bloc enabled Christian radicals to exert ideological influence. My findings demonstrate how parties shape the trajectories and outcomes of radicalization and underscore the importance of comparative analysis of left and right movements to explain their political legacies.