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 made frequently to change tax laws, often with the backing of specific interest groups. Organizations making such proposals include Citizens for Tax Justice, Americans for Tax Reform, Americans for Tax Fairness, Citizens for an Alternative Tax System, Americans For Fair Taxation, and FreedomWorks. Various proposals have been put forth for tax simplification in Congress including the "Fair Tax Act" and various Flat tax plans. Proponents of a consumption tax argue that the income tax system creates perverse incentives by encouraging taxpayers to spend rather than save: a taxpayer is only taxed once on income spent immediately, while any interest earned