Representative democracy and marginal rate progressive income taxation

This paper develops a political economy model that is consistent with the fact that democracies have a preference for increasing marginal tax rates on income. We present a model in which there is an exogenous set of political parties with preferences over the set of admissible tax schedules. This set contains virtually any increasing and piecewise linear continuous function. Each party decides whether or not to present a candidate for election. There is a fixed cost of running. The elected candidate implements one of her preferred tax policies. Our main results provide conditions under which a Strong Nash Equilibrium exists, and a tax schedule with increasing marginal tax rates is implemented in some Nash Equilibria and in any Strong Nash Equilibrium.