A dynamic model of political change among party activists

In this article, we develop a dynamic model of aggregate attitudinal change among party activists in order to better understand the process by which new issues/cleavages divide major political parties. We build on existing research by developing a model of change that incorporates both conversion among continuing activists and the replacement of previous activists with newcomers who hold different views. We first explore such change among activists of the two major parties in the United States on the abortion issue. We then consider a number of alternative specifications of the model in order to generalize our findings. We conclude that conversion among continuing activists contributes in a substantial way to aggregate change among party activists by influencing the level of change, accelerating the change process, and sustaining change over time.