Well that's going to end when the Bush tax cuts expire in 2010.
Right Wing water-carrier Arthur Laffer's own curve states that changes in the rate of taxation impact the incentive to earn taxable income. At the ends of the Laffer curve, both a 0% income tax rate and a 100% tax rate generate no revenue, thus a revenue maximising taxation rate lies somewhere in between.
This means that to generate maximum revenue, the tax rate should be neither too high,
nor too low, relative to GDP.
Bush's tax rates were not only too low to generate premium revenue streams, but were also based on false GDP numbers due to the non-existent trillions that were supposedly produced by the financial sector, that turned out to not really exist.
Since the GDP was inflated, even the Laffer curve now demands a higher rate of taxes for maximum revenue, though Laffer, the political shill that he is, has been trying to say otherwise, in contradiction of his own theory.