In this paper we use a simple median voter model to analyze the effects of tax systems with differing degrees of progressivity. We find that relatively high taxes on middle incomes have two important advantages: On the one hand, they help to ensure that all citizens are better off than they would be in a world without government, and on the other hand, they reduce the tax level chosen in the election. Therefore, the progression in the middle income range not only ensures that Wicksell's requirement of ex post efficiency of the tax system is achieved, it may also increase social welfare.