A Probabilistic Voting Model of Progressive Taxation with Incentive Effects

The purpose of this work is to show under what conditions a marginally progressive income tax emerges as the result of political competition between two parties when labor is elastically supplied and candidates are uncertain about voters' decisions on election day. Assuming a decreasing wage elasticity of labor supply, if we follow Coughlin and Nitzan (1981), only marginal-rate progressive taxes are chosen by both candidates in equilibrium. If, instead, we adopt Lindbeck and Weibull's (1987) probabilistic voting model, the equilibrium tax schedule will be progressive as long as the political power of the rich voter is sufficiently low. The degree of progressivity decreases with population polarization.