Previous studies have suggested that Americans who regularly attend church develop important civic skills which facilitate their participation in politics (e.g., see Verba et al. 1995). Churches were also heralded as important repositories of social capital, particularly for disadvantaged minority groups who have fewer opportunities to develop civic skills (Putnam 2000). Moreover, social capital theorists have argued that homogenous congregations foster the development of bonding (in-group) rather than bridging (out-group) social capital. One important fact, which has not been examined closely in the voting literature, is that American churches are still highly segregated by race/ethnicity according to a recent Gallup Poll (2004). Also unclear in the literature is the differential impact of bonding versus bridging social capital on political participation. Scholarship by Putnam (2000) and Gutmann (1998) suggests that heterogeneity within associational memberships is healthier for democratic citizenship than those with more homogenous memberships. This paper evaluates this claim and investigates whether or not bonding social capital fosters or discourages political participation for both white-majority voters and minorities. Using Bayesian statistical methods, this study, for the first time, conducted a national, cross-racial analysis of whites, Blacks, Latinos, and Asian Americans based on data from the General Social Survey (2002), National Election Studies (2000), and the Pilot National Asian American Political Survey (2001). The finding suggests that church attendance is significant and positively associated with voting participation among racial/ethnic groups that attend churches with mostly homogenous memberships. Contrary to the negative implications purported to stem from the "dark side" of social capital, the results of this research show that bonding social capital positively influences participation in politics. These findings lead to important implications for understanding the mobilization of immigrant communities, a group that political parties rarely attempt to mobilize (Kim 2007; Wong 2006).