"The events and policies that have pushed deficits to these high levels in the near term, however, were largely outside the new Administration’s control. If not for the tax cuts enacted during the presidency of George W. Bush that Congress did not pay for, the cost of the wars in Iraq and Afghanistan that were initiated during that period, and the effects of the worst economic slump since the Great Depression (including the cost of steps necessary to combat it), we would not be facing these huge deficits in the near term."
A.k.a. Obama inherited the deficit from the Bush administration and the gravely irresponsible Republican congress. This is according to an article from the Center on Budget and Policy Priorities that the nice people at Goldman Sachs shared with me. More here: