ABSTRACT
Since the 1950s the political parties have changed in their constituencies and concerns. The positions of the parties on major issues have changed. The process by which the electorate reacts to party positions is likely to be gradual and erratic; voters have limited information and inaccurate perceptions, and acquiring information is costly. Despite that, there are signs that tensions and changes within the Republican Party emerged somewhat earlier than among Democrats, so the analysis will begin with the Republican Party. The Republican Party of the 1950s had internal tensions. The party contained two wings, divided by geography and philosophy. While conservatives and moderates were engaging in intraparty battles and the electoral base of the party was shifting, other developments were providing more support for the conservative cause. Much as with the Republican Party, the Democratic Party has undergone significant change since the early 1960s in its electoral bases and concerns.
