The first task is to see whether there has been a systematic weakening of the channels of electoral, party, and civic activism. The second is to examine the most plausible explanations to account both for differences among nations and for trends over time. The most common explanation for longterm developments in political participation comes from modernization theories advanced by Daniel Bell, Ronald Inglehart, and Russell Dalton, among others, suggesting that common social trends – such as rising standards of living, the growth of the service sector, and expanding educational opportunities – have swept through postindustrial societies, contributing to a new style of citizen politics in Western democracies. This process is believed to have increased demands for more active public participation in the policy-making process through direct action, new social movements, and protest groups, while weakening deferential loyalties and support for traditional hierarchical organizations and authorities such as churches, parties, and traditional interest groups.

By contrast, institutional accounts emphasize the way in which the structure of the state sets opportunities for participation, exemplified in arguments by Powell and by Jackman that electoral laws, party systems, and constitutional frameworks help explain differences in voting turnout among nations. Trends in participation can also be accounted for by changes in the rules of the game, such as the expansion of the franchise and reforms in campaign spending laws. Agency theories, exemplified by Rosenstone and Hansen, focus on the role of traditional mobilizing organizations in civic society, notably the ways in which political parties, trade unions, and religious groups recruit, organize, and engage activists.