It is also mentioned in Trickle Down Theory and Tax Cuts for the Rich that if the purpose of a national income tax is to increase revenues, the history proves to us (there are numerous examples cited in the book spaning a numer of different administrations and periods) that reducing tax rates does in fact increase revenue.
Conversely, the notion of raising income tax rates on the most wealthy seems to signal that the main purpose of our tax code is not the raising of revenue, but rather the redistribution of what is believed to be a fixed amount of wealth.