Income tax in the United States increase complexity, irrespective of the system's flatness or lack thereof. Income tax is also levied by most U.S. states and many localities on individuals, corporations, estates, and trusts. These taxes are in addition to federal income tax and are deductible for federal tax purposes. State and local income tax rates vary from 1% to 16% of taxable income. Some state and local income tax rates are flat (single rate) and some are graduated. State and local definitions of what income is taxable vary highly. Some states incorporate the federal definitions by reference. Taxable income is defined separately and differently for
Income tax in the United States direct tax on the basis of the source of the income. The Amendment removed the need for the income tax to be apportioned among the states on the basis of population. Income taxes are required, however, to abide by the law of geographical uniformity. Some tax protesters and others opposed to income taxes cite what they contend is evidence that the Sixteenth Amendment was never properly ratified, based in large part on materials sold by William J. Benson. In December 2007, Benson's "Defense Reliance Package" containing his non-ratification argument which he offered for sale on the Internet, was ruled by