Atkinson and Stiglitz show that with weakly separability, differential commodity taxes are unnecessary given an optimal nonlinear income tax. Deaton showed that with an optimal linear progressive income tax, commodity taxes are superfluous under weakly separable and linear Engel curves. Using...

It has now been nearly three decades since the publication of two important volumes that laid out many of the details of how one might implement a progressive consumption tax (Institute for Fiscal Studies, 1978; U.S. Treasury, 1977). Over the years since, many contributions have analyzed the...