The original focus of Supple Side Economics was on bringing down the top marginal tax rate of income tax to improve incentives to work, save, and invest.
Now the focus is on bringing down every rate but the top one. Even Grover Norquist of Americans for Tax Reform praises Republicans for their willingness to agree to a rise in the Top Marginal Rate from 35% to 39.6% (actually higher due to phaseouts of personal exemptions and itemized deductions) because the fiscal cliff deal made permanent all other rates but the top one.
Never mind how much higher the now permanent rates are than the the two rates of 15% and 28% of President Reagan, and even the addition of the 31% rate of President George H.W. Bush.
Where have you gone Joe DiMaggio?