As social and political movements gain enough strength to seriously challenge the more powerful forces that legitimate and protect status quo arrangements in a country, a society, an institution, an agency, an organization, or other social system, those in authority who are being challenged may reach out to and attempt to bring the challengers into the system as participants. This formalized inclusion of challengers into the authority system that they are challenging is the essence of co‐optation. An early and influential work on understanding co‐optation is Philip Selznik's (1949) study of how the Tennessee Valley Authority targeted and eventually absorbed local elites and community activists into its administrative structure in order to transform local opposition to TVA policies into support for those policies. Gamson's (1990) analysis of 53 challenging groups, in which he defined co‐optation as challengers gaining access to the public policy process but without achieving actual policy changes, is also important.