Critical Elections and Political Realignments in the USA: 1860–2000

The sequence of US presidential elections from 1964 to 1972 is generally regarded as heralding a fundamental political realignment, during which time civil rights became as important a cleavage as economic rights. In certain respects, this realignment mirrored the transformation of politics that occurred in the period before the Civil War. Formal models of voting (based on assumptions of rational voters, and plurality-maximizing candidates) have typically been unable to provide an account of such realignments. In this paper, we propose that US politics necessarily involves two dimensions of policy. Whatever positions US presidential candidates adopt, there will always be two groups of disaffected voters. Such voters may be mobilized by third party candidates, and may eventually be absorbed into one or other of the two dominant party coalitions. The policy compromise, or change, required of the successful presidential candidate then triggers the political realignment. A formal activist-voter model is presented, as a first step in understanding such a dynamic equilibrium between parties and voters.