An income tax was first collected during the Civil War from 1862 to 1872. During the administration of President Grover Cleveland, the federal government again levied an income tax, enacted by Congress in 1894. However, the Supreme Court ruled it unconstitutional the following year. Supporters of an income tax were forced then to embark on the lengthy process of amending the Constitution. Not until the Sixteenth Amendment was ratified in 1913 was Congress given the power “to lay and collect taxes on incomes, from whatever source derived, without apportionment among the several states, and without regard to any census of enumeration.”
Arguing that the income tax is unconstitutional, as some do, is simply ignorance. It’s in an amendment, just like freedom of speech, right to bear arms and women’s suffrage.