  This in turn gave renewed impetus to methodological individualism, because it allowed theorists to diagnose with unparalleled precision the errors that social theorists could be (and often were) led into if they ignored the action-theoretic level of analysis. Methodological individualism became important, not as a way of avoiding the political thought-crime of “collectivism,” but rather as a way of avoiding demonstrably fallacious inferences about the dynamics of collective action. For example, the traditional “interest group” theory of democratic politics generally presupposes that groups who share a common interest also have an incentive to promote that interest, by lobbying politicians, funding research, and so on. Olson’s major contribution was to have driven home the point that the existence of such a common interest just as often generates a free-rider incentive. Individuals would benefit from acting to promote that interest, but they would benefit even more by sitting back while the other members of the group acted to promote it. As a result, no one may act to promote it.  However, Olson confined this observation to large groups. The prisoner’s dilemma, on the other hand, demonstrated the ubiquity of this incentive structure.