WHENCE THE DEFICIT?

The first category — the business cycle — accounts for 37 percent of the $2 trillion swing. It’s a reflection of the fact that both the 2001 recession and the current one reduced tax revenue, required more spending on safety-net programs and changed economists’ assumptions about how much in taxes the government would collect in future years.About 33 percent of the swing stems from new legislation signed by Mr. Bush. That legislation, like his tax cuts and the Medicare prescription drug benefit, not only continue to cost the government but have also increased interest payments on the national debt.Mr. Obama’s main contribution to the deficit is his extension of several Bush policies, like the Iraq war and tax cuts for households making less than $250,000. Such policies — together with the Wall Street bailout, which was signed by Mr. Bush and supported by Mr. Obama — account for 20 percent of the swing.About 7 percent comes from the stimulus bill that Mr. Obama signed in February. And only 3 percent comes from Mr. Obama’s agenda on health care, education, energy and other areas.

-- Tim Fernholz