Interdependence is a fundamental fact of social behavior whether one is studying political behavior, political institutions or organizational decision-making, yet remains persistently difficult to integrate into most empirical research. This talk addresses this issue in two parts. In the first part, I lay out a parsimonious formal framework, called “conditional choice,” that is grounded in behaviorally valid assumptions and the dynamics of conditional decision-making. In the second part, I “engineer” a social theory of voter turnout that can be tested against the contemporary mainstream theory of political participation. The evidence suggests that differences in social network structure, not individual costs and benefits, account for variation in the rate of participation across different demographic groups. These findings overturn the long- standing conventional wisdom that people vote because they have more civic resources, a greater sense of civic duty, or a more abiding interest in politics than do non-voters.