Why are some taxes "more equal than others"?

This paper examines efficiency rationales behind uniformity of taxation for public projects. Let a benevolent risk neutral 'constitutional designer' to set an optimal cost-sharing rule for a legislature operating under majority rule. Then the designer will choose 'more equal taxes' for a country with more homogeneous tastes, which is in accord with a popular view. Higher quality projects provide an additional reason for this choice. Moreover, an exogenous requirement to use broader supermajority may also lead to more uniformity.