<P> Taxation of income in the United States has been practised since colonial times . Some southern states imposed their own taxes on income from property, both before and after Independence . The Constitution empowered the federal government to raise taxes at a uniform rate throughout the nation, and required that "direct taxes" be imposed only in proportion to the Census population of each state . Federal income tax was first introduced under the Revenue Act of 1861 to help pay for the Civil War . It was renewed in later years and reformed in 1894 in the form of the Wilson - Gorman tariff . </P> <P> Legal challenges centered on whether the income tax then in force constituted a "direct tax". In the Springer v. United States case of 1881, the Supreme Court upheld the tax regime then in force . An 1894 statute was ruled unconstitutional in the case of Pollock v. Farmers' Loan and Trust Company . In response, the Sixteenth Amendment, proposed in 1909 and becoming law in 1913, cancelled the "apportionment" requirement for income taxes . Federal income tax was thereupon reintroduced in the Revenue Act of 1913 . In the case of Brushaber v. Union Pacific Railroad Company (1916), the 1913 Act was ruled to be constitutional . A separate excise tax was also imposed on corporations . </P>

The first time the united states enacted a temporary income tax was