Using time series data from 15 post-World War II congressional elections, a nine-equation social indicators model of aggregate American political behavior is estimated. Six exogenous social and economic conditions and nine endogenous political variables are linked in a schematic flow across three sectors of the national polity. Findings indicate that relatively short-term social and political conditions exert greater effects on election outcomes than do long-term partisan alignments. The party composition of the executive and legislative branches of the federal government affects defense expenditures as a proportion of all budgetary outlays, but has only weak impact on health and education expenses. Criticisms and suggestions for future work are discussed.