Final answer:
The Sixteenth Amendment to the U.S. Constitution, ratified in 1913, legalized the federal income tax, which was necessary to replace revenue lost from lowered tariffs and fund government operations. The amendment enabled a federal income tax without apportionment among states or based on the Census, establishing a progressive tax system.
Step-by-step explanation:
Ratification of the Sixteenth Amendment
The ratification of the Sixteenth Amendment to the U.S. Constitution was essential in legalizing the federal income tax. Prior to its ratification, there was debate over the constitutionality of a federal income tax. The Supreme Court had previously deemed federal income tax laws unconstitutional, prompting the need for a constitutional amendment to expressly authorize it.
In response to the need for a steady source of government revenue and the reduction of tariffs, Congress passed, and the states ratified the Sixteenth Amendment on February 3, 1913. This amendment granted Congress the power to levy a federal income tax without apportioning it among the states or basing it on the U.S. Census. Initially imposed during the Civil War, the federal income tax was a contentious issue until the passing of this amendment, which permanently established its legitimacy.
In the context of social and political pressure, including from the Populists and Progressives, the Sixteenth Amendment established a progressive tax system, primarily affecting the wealthy. Over the years, as the exemption level declined and tax rates increased, more Americans fell under the obligation to pay federal income taxes, which has been a significant source of revenue for the federal government.