In an earlier article in these pages, Prof. Erik M Jensen examined the history of the Direct-Tax Clauses of the Constitution and concluded that two proposals for fundamental tax reform--the flat tax and the Unlimited Savings Allowance (USA) tax--would be unconstitutional as unapportioned direct taxes. In this essay Prof. Zelenak disagrees with that conclusion. Zelenak accepts, for the sake of argument, Jensen's reading of the historical records, but differs with Jensen on how to apply the Direct-Tax Clauses to forms of taxation not imagined in the eighteenth century. He suggests that a conscientious legislator could decide that neither proposal would violate the Direct-Tax Clauses. Zelenak also argues that even if the proposals were viewed as unapportioned direct taxes, they would nevertheless be income taxes within the meaning of the Sixteenth Amendment, and thus would be relieved of the apportionment requirement.
Lawrence A. Zelenak, Radical Tax Reform, the Constitution, and the Conscientious Legislator, 99 Columbia Law Review 833-856 (1999)