The 16th Amendment to the U.S. Constitution gave the federal government the right to levy an income tax. Congress passed the 16th Amendment on July 2, 1909, and it was ratified or approved on Feb. 3, 1913.
The 16th Amendment was a response to the needs of a growing nation. The first American income tax originated in 1861 when the costs of the Civil War became too much for the nation to bear. In 1872, however, this income tax law was repealed. In 1894, Congress tried once again to collect income taxes from Americans with a two-percent tax on anyone making over $4,000, but this law was overturned by the Supreme Court.
In 1909, conservatives in Congress then asked for an amendment to the Constitution to institute the income tax once again. Surprisingly, the amendment, which needed the approval of three-fourths of all states, was ratified. In 1913 when the amendment was enacted, only about one percent of the population was charged an income tax, which consisted of one percent of net income.