Voting over selfishly optimal income tax schedules with tax-driven migrations

We study majority voting over selfishly optimal nonlinear income tax schedules proposed by a continuum of workers who can migrate between two competing jurisdictions. Both skill level and migration cost are the private information of each worker who will propose an allocation schedule that maximizes the utility of her own type. We identify reasonable scenarios in which the first-order approach applies and hence the second-order sufficient condition for incentive compatibility is fulfilled; otherwise, we need to apply the ironing surgery developed by Brett and Weymark (Games Econ Behav 101:172–188, 2017). Under quasilinear-in-consumption preferences, we show that the tax schedule proposed by the median skill type is the Condorcet winner, and provide a complete characterization of this tax schedule. While this schedule features negative marginal tax rates for low-skilled workers, it features positive rates for high-skilled workers with small migration elasticities; the marginal tax rates at the bottom and top skill levels cannot be unambiguously signed. Moreover, we detail the conditions under which migration induces uniformly higher or lower equilibrium marginal tax rates facing both low- and high-skilled workers than their counterparts in autarky, which leads us to conclude that geographic mobility does not always limit the government’s ability to redistribute incomes via tax-transfer systems.