These explanations are very different in their theoretical premisses and the causal processes they emphasize, but they
all suggest that long-term changes in the social and political conditions of advanced industrial societies may be eroding
public support for the political process. If we accept this brief review of the literature, it suggests the type of empirical
evidence we should collect. Ideally, we should assess these theories with long-term trend data, especially data which
begin in the more halcyon period of the late 1950s and early 1960s. Although data from the 1980s and 1990s are
relevant to the research question, they may come too late to test (or track) changes in public sentiments. In addition, we
should be sensitive to the various levels and types of political support as outlined in Table 3.1, and we would like to
collect varied measures of authority, regime, and community support. It would be ideal if comparable measures were
available cross-nationally as well as cross-temporally.
These data needs are difficult to fulfill. There is a very long series of election studies and other opinion surveys for the
United States that provides a rich, though not ideal, database for studying political support. In many other nations,
however, the data-series is normally much thinner. The most extensive data are available for more recent years, but the
baseline measures from earlier periods are often lacking. Within these constraints, we have attempted to assemble long term
trends in political support from the national election study series, or a comparable data series, for as many
advanced industrial democracies as possible. We emphasized the temporal dimension over the cross-national
dimension. The results, we believe, provide a comparative overview of trends in political support in advanced
industrial democracies.