Final answer:
The Sixteenth Amendment, ratified in 1913, introduced the Federal income tax during the Progressive Era. It allowed Congress to tax income directly without apportionment among the states, targeting initially only the wealthiest Americans.
Step-by-step explanation:
The Constitutional Amendment passed during the Progressive Era that created the Federal income tax is the Sixteenth Amendment. Ratified in 1913, this amendment allowed Congress to levy an income tax without apportioning it among the states or basing it on the United States Census. Initially, this tax was designed so that only the wealthiest 5 percent of households would pay taxes, with a rate ranging from 1 percent to a maximum of 7 percent for the wealthiest Americans.
The enactment of the Sixteenth Amendment followed the advocacy of the Populists and Progressives and the recognition that there needed to be a more equitable form of taxation than the tariffs, which disproportionately affected the working poor. The legislation for the income tax was part of a broader fiscal reform effort, which also included reducing tariffs through the Revenue Act of 1913 or the Underwood Tariff Act.