The first individual income tax in the United States was enacted in 1861 to finance the Civil War. In 1862, the first year these taxes were actually collected, the rate was 3% of income over $600 and an additional 2% of income over $10,000. After the war was over, the US government no longer needed the revenue and in 1872 congress repealed the income tax.
In 1909, income tax was again proposed, but Republicans in the Senate effectively killed the measure through a compromise that allowed a one percent tax on corporate income over $5,000 and sponsored a constitutional amendment that would allow income to be taxed by the federal government without regard to state apportionment or the census as required by the constitution. Senate Republicans were confident the individual states would never approve the amendment, but by 1912 the Democratic Party had won control of most state elections and both houses of Congress. On February 25, 1913, the required 36 states had approved the Sixteenth Amendment and on October 3, 1913 both houses of Congress passed the 1913 Tax Act.
The first tax was only on “high income” individuals, defined as those who made over $3,000 for singles and $4,000 for married taxpayers. The tax rate gradually increased from 1% to a top rate of 7% based on total income.
Outright is secure.