Social capital and community activity are thought to increase voter turnout, but reverse causation and omitted variables may bias the results of previous studies. This article exploits saint's day fiestas in Mexico as a natural experiment to test this causal relationship. Saint's day fiestas provide temporary but large shocks to the connectedness and trust within a community, and the timing of these fiestas is quasi-random. For both cross-municipality and within-municipality estimates, saint's day fiestas occurring near an election decrease turnout by 2.5 to 3.5 percentage points. So community activities that generate social capital can inhibit political participation. These findings may give pause to scholars and policy makers who assume that such community activity and social capital will improve the performance of democracy.
* Department of Political Science, University of California, Los Angeles; and Department of Government, Harvard University, respectively (email: email@example.com). Both authors contributed equally, and they wish to thank Alberto Alesina, Steve Ansolabehere, David Broockman, Gloria Chao, Stephen Coate, Ana De La O, Ryan Enos, Jonathan Gruber, Andy Hall, Jens Hainmueller, Eitan Hersh, Christopher Karpowitz, Stephen Knack, Gabe Lenz, Jeff Lewis, Krista Loose, Michele Margolis, Nathan Nunn, Kay Schlozman, Dhavan Shah, Dina Sherzer, Joel Sherzer, Jim Snyder, Michael Tesler, Gelin Valencia and seminar participants at MIT for their comments and support. Supplementary material for data replication and an online appendix are available at http://dx.doi.org/doi:10.1017/S0007123412000713.