"In order to raise revenue to fund the Civil War, the income tax was introduced in the United States with the Revenue Act of 1861. It was a flat rate tax of 3% on annual income above $800.

The following year, this was replaced with a graduated tax of 3-5% on income above $600 in the Revenue Act of 1862, which specified a termination of income taxation in 1866.

The Socialist Labor Party advocated for a graduated income tax in 1887.

The Populist Party 'demanded a graduated income tax' in their 1892 platform.

The Democratic Party, led by William Jennings Bryan, advocated the income tax law passed in 1894, and proposed an income tax in their 1908 platform.

Federal income tax was proposed by {president} William H. Taft in 1909 as a way to lower tariffs.

On June 16, 1909, President Taft proposed a constitutional amendment in an address to Congress to allow federal income taxes on individuals and an excise tax 'upon the privilege of doing business as an artificial entity and of freedom from a general partnership liability enjoyed by those who own the stock.'

On July 12, 1909, the resolution proposing the Sixteenth Amendment was passed by the Sixty-first Congress and submitted to the state legislatures. Support for the income tax was strongest in the western states and opposition was strongest in the northeastern states. The governor of New York, Charles Evans Hughes, who a few years later became a Supreme Court justice, opposed the income tax amendment because he believed 'from whatever source derived' implied that passage would confer the federal government with the power to tax state and municipal bonds and thus excessively centralize government power.

The presidential election of 1912 was contested between three advocates of an income tax. On February 25, 1913, the Secretary of State Philander Knox proclaimed that the amendment had been ratified by the necessary three-fourths of the states, and thus had become part of the Constitution. An income tax, the Revenue Act of 1913, was shortly passed by the Congress."

{The federal income tax was made official by the Revenue Act of 1913 as signed by Democrat Woodrow Wilson.

Theodore Roosevelt may have supported the federal income tax but had little to do with proposing it or imposing it.}