I am a public school teacher in California. Today as I was preparing a lesson plan, I noticed that the high school history textbook I am using mentions the Sixteenth Amendment exactly twice:
Once when they printed the text of the U.S. Constution, and a second time that I will share in its entirety.
"Federal Income Tax. With lower tariff rates, the federal government had to replace the revenue that tariffs had previously supplied. Ratified in 1913, the Sixteenth Amendment legalized a graduated income tax, which provided revenue by taxing individual earnings and corporate profits.
Under this graduated tax, larger incomes were taxed at higher rates than smaller incomes. The tax began with a modest tax on family incomes over $4,000 and ranged from 1 percent to a maximum of 6 percent on incomes over $500,000. Initially, few congressmen realized the potential of the income tax, but by 1917, the government was receiving more money on the income tax than it had ever gained from tariffs. today, income taxes on corporations and individuals represent the federal government's main source of revenue."