The previous chapter demonstrated how a series of regime changes in Europe, southern Africa, and the United States converged with paradoxes arising from South Africa’s maturing industrial economy to make apartheid a more salient policy problem for Americans. These transitions provided more opportunities for domestic activists to exploit the ensuing vulnerabilities. This chapter focuses on the continuing processes that affected the probability of anti-apartheid mobilization penetrating the policy environment. The approach here contrasts with more traditional stimulus-response explanations of insurgency that view activism primarily as a set of reactions to conventional problems in established policymaking arenas. This analysis instead addresses the long-term development of anti-apartheid activism, its rise and decline in salience, and the ongoing struggle to make the issue appear actionable to the public. It thus stands out from classical approaches that view activism as only reactive.