From "Deficit Study Disputes Role of Economy" in today's New York Times:

When President Bush and his advisers talk about the widening federal budget deficit, they usually place part of the blame on economic shocks ranging from the recession of 2001 to the terrorist attacks that year.

But a report released on Monday by the nonpartisan Congressional Budget Office estimated that economic weakness would account for only 6 percent of a budget shortfall that could reach a record $500 billion this year.

[. . .]

The new numbers confirm what many analysts have predicted for some time: that budget deficits in the decade ahead will stem less from the lingering effects of the downturn and much more from rising government spending and progressively deeper tax cuts.