Taxes and Turnout

We develop a model of political competition with endogenous turnout and endogenous platforms. Parties face a trade-off between maximizing their base and getting their supporters out to vote. We study the implications of this framework for non-linear income taxation. In equilibrium, both parties propose the same tax policy. This equilibrium policy is a weighted combination of two terms, one reflecting the parties' payoff from mobilizing their own supporters, one reflecting the payoff from demobilizing the supporters of the other party. The key determinant of the equilibrium policy is the distribution of the voters' party attachments rather than their propensity to swing vote. Our analysis also provides a novel explanation for why even left-leaning parties may not propose high taxes on the rich.