Maybe, maybe not. This is a tough question to answer definitively, and the subject almost always gets political, and I prefer to keep this blog about sound ideas and facts instead of political stances.
Okay, with the American business sector acting as if it's on "hold" until government policy changes (taxes, regulation, etc.) are clear or in effect, we wait and debate. One huge debate is whether Congress should allow the "Bush Tax Cuts" of 2001 and 2003 to expire as scheduled, or if we should raise some rates and not the others or maintain status quo.
It is widely held, by those who believe cuts in marginal income tax rates will stimulate the economy and thus actually increase tax revenues, that there's a lag-effect for the stimulative results to appear. Some of the most ferocious debating and punditry right now is whether such tax cuts really do lead to higher, not lower, federal revenues.
With that in mind, here is some data right from the CBO and OMB:
US Budget Receipts (just from individual income taxes)
2000 was $1,004 billion
2001 was $994 billion, down 1.0%
2002 was $858 billion, down 13.7%
2003 was $794 billion, down 7.5%
2004 was $809 billion, up 1.9%
2005 was $927 billion, up 14.6%
2006 was $1,043 billion, up 12.5%
2007 was $1,163 billion, up 11.5%
2008 was $1,219 billion, up 4.8%
Tax cuts were approved in '01 and '03, so their effects likely started being felt in '02 and '04.
Federal receipts from income taxes grew a lot each year starting in 2004, while the economy did not grow at the same rate. Way too many variables would factor in here for the results to be conclusive, but the income tax cuts do correspond to increased revenue to the government.
(Here's the US GDP data for the same time-frame)
2000 was $9.76 trillion
2001 was $10.1 trillion, up 3.5%
2002 was $10.4 trillion, up 3.0%
2003 was $10.9 trillion, up 4.8%
2004 was $11.6 trillion, up 6.4%
2005 was $12.4 trillion, up 6.8%
2006 was $13.1 trillion, up 5.6%
2007 was $13.7 trillion, up 4.5%
2008 was $14.6 trillion, up 6.6%
