Why isn the 16th Amendment sufficient?
http://caselaw.lp.findlaw.com/script…=240&invol=103 STANTON v. BALTIC MINING CO, 240 U.S. 103 (1916) “…the provisions of the 16th Amendment conferred no new power of taxation, but simply prohibited the previous complete and plenary power of income taxation possessed by Congress from the beginning from being taken out of the category of indirect taxation to which it inherently belonged, and being placed [240 U.S. 103, 113] in the category of direct taxation subject to apportionment by a consideration of the sources from which the income was derived,-that is, by testing the tax not by what it was, a tax on income, but by a mistaken theory deduced from the origin or source of the income taxed.
