Convergence and divergence in dynamic voting with inequality

The original formulation of the median voter theorem predicts parties’ political convergence in a static setup, under two key assumptions : voters preferences being fixed and parties being opportunistic (purely office-motivated). Drawing on recent empirical findings about the evolution of voters’ political preferences, this paper verifies whether the median voter theorem’s results hold when (i) the control variables that influence voters’ preferences endogenously evolve over time, and (ii) parties are not opportunistic. We present a dynamic two-party voting model in which voters’ preferences evolve over time depending on observable common factors and unobservable idiosyncratic characteristics. In such a setting, the convergence of parties’ platforms to the centre is a special case within a range of results that include instability and equilibria at one of the extremes. Moreover, convergence of parties’ platforms is achieved not as the result of electoral strategies, but when neither party has enough support to pursue its agenda.