This article examines why people violate rationality and take part in their communities, differentiating by types of participation, particularly political versus other, more communal types of participation. The authors argue that trust plays an important role in participation levels, but contrary to more traditional models, the causal relationship runs from trust to participation. In addition, the authors posit that trust is strongly affected by economic inequality. Using aggregated American state-level data for the 1970s, 1980s, and 1990s, the authors present a series of two-stage least squares models on the effects of inequality and trust on participation, controlling for other related factors. Findings indicate that inequality is the strongest determinant of trust and that trust has a greater effect on communal participation than on political participation.