Many economists believe that social capital provides substantial economic benefits and some political scientists argue that social capital plays an important role in civic society by underpinning stable democracies. Notably, Robert Putnam in Bowling Alone: America's Declining Social Capital argues that declining social capital in the United States is undermining democracy.
Shanker Satyanath, Nico Voigtlander and Hans-Joachim Voth in their recent working paper entitled "Bowling for Fascism: Social Capital and the Rise of the Nazi Party in Weimar Germany, 1919-33" consider the dark side of social capital by looking at how networks of civic associations (e.g., bowling clubs, choirs, and animal breeders) contributed to the rise of the Nazi Party and the downfall of democracy in interwar Germany. There is a good review of this paper over at the NEP-HIS Blog by Ronan McCarry (a final-year BSc Economics student at Queen's University). Congratulations are due to Chris Colvin and Bernardo Batiz-Lazo for encouraging students to write these reviews.