Zackie Achmat has mounted one of the most effective responses to the AIDS crisis through his grassroots social movement, the Treatment Action Campaign (TAC), mobilizing some 10,000 volunteers in more than 200 branches across South Africa. His accomplishments netted him a Nobel Peace Prize nomination in 2004.

TAC combines a popular movement with partnerships that link various sectors of society, including trade unions, faith-based groups, local and international citizen organizations, and businesses. TAC members and supporters are regularly summoned to participate in mass actions. Altogether, TAC's members and active supporters are equivalent to about 10 percent of the population that needs antiretroviral treatment in South Africa. TAC efforts have helped dramatically cut the price of antiretroviral and other essential drugs.

TAC has successfully pushed the South African government to roll out antiretroviral therapies through its public health care system, provide treatment to HIV-positive women during childbirth to decrease the transmission of HIV from mother to child, and increase the levels of public literacy around the complexities of treatment.

Thanks to its political savvy, TAC's influence extends beyond the HIV/AIDS crisis. Citizen organizations and donors now view TAC as a role model for defending socioeconomic rights and advocating for constitutional rights in South Africa.