Income tax return for taxation also vary, making comparisons all the more difficult. Countries that tax income generally use one of two systems: territorial or residential. In the territorial system, only local income – income from a source inside the country – is taxed. In the residential system, residents of the country are taxed on their worldwide (local and foreign) income, while nonresidents are taxed only on their local income. In addition, a very small number of countries, notably the United States, also tax their nonresident citizens on worldwide income. Countries with a residential system of taxation usually allow deductions or credits
Income tax in the United States a tax on property and it certainly is not a capitation tax; therefore, it need not be apportioned. ... Congress has the power to impose taxes generally, and if the particular imposition does not run afoul of any constitutional restrictions then the tax is lawful, call it what you will. Federal and state income tax rates have varied widely since 1913. For example, in 1954, the federal income tax was based on layers of 24 income brackets at tax rates ranging from 20% to 91% (for a chart, see Internal Revenue Code of 1954). Below is a table of historical