In a monologue on the Bush tax cuts, the talk radio host mused:

Looked at within the prism of liberty and freedom, as our founding documents spell out, the Declaration, the Constitution, in nowhere in any of our founding documents was it ever said that people earning X would be punished for it.  It was never said in our founding documents that people earning X would share a greater burden of funding the government than people who didn't.  Where does all this talk start?

The answer is that it started with Abraham Lincoln, and the Congress that helped him to defeat the Confederacy:

When the Civil War erupted, the Congress passed the Revenue Act of 1861, which restored earlier excises taxes and imposed a tax on personal incomes. The income tax was levied at 3 percent on all incomes higher than $800 a year. This tax on personal income was a new direction for a Federal tax system based mainly on excise taxes and customs duties. Certain inadequacies of the income tax were quickly acknowledged by Congress and thus none was collected until the following year...

On July 1, 1862 the Congress passed new excise taxes on such items as playing cards, gunpowder, feathers, telegrams, iron, leather, pianos, yachts, billiard tables, drugs, patent medicines, and whiskey... The 1862 law also made important reforms to the Federal income tax that presaged important features of the current tax. For example, a two-tiered rate structure was enacted, with taxable incomes up to $10,000 taxed at a 3 percent rate and higher incomes taxed at 5 percent. A standard deduction of $600 was enacted and a variety of deductions were permitted for such things as rental housing, repairs, losses, and other taxes paid. In addition, to assure timely collection, taxes were "withheld at the source" by employers.