Social capital is a relatively new term in sociology and political science. The theoretical perspective is examined with special reference to the studies of J. Coleman. R. Putnam's "Making democracy work" and F. Fukuyama's "Trust" are discussed as misleading applications of the concept to comparative analysis of capitalism, in a moment of difficulty for traditional political economy. The article maintains that actually comparative analysis of capitalism can usefully refer to the idea of social capital, but integrating this perspective in the framwork of the political economy, far from the neo-functionalist and hyper-culturalist perspective of Putnam and Fukuyama, a sort of "american ideology". This could be a way to introduce "society" in the old analytical game between state and market.