From the New York Times :
To relate this specifically to the debt-ceiling debate, we’re not raising the debt ceiling because of the new policies passed in the past two years. We’re raising the debt ceiling because of the accumulated effect of policies passed in recent decades, many of them under Republicans. It’s convenient for whichever side isn’t in power, or wasn’t recently in power, to blame the debt ceiling on the other party. But it isn’t true.
Full coverage: U.S. debt-ceiling debate
The Bush tax cuts will decide the debate