The big reason to make a deal before January 1, 2013 was that detonating the "austerity bomb" would impose 3.5% of fiscal contraction on the U.S. economy in 2013, and send the U.S. into renewed recession. It was worth making a good-enough deal--sensible long-run revenue increases and tax cuts to close the long-run fiscal gap plus enough short-term fiscal stimulus to make the net fiscal impetus +1.0% of GDP--in order to avoid renewed recession.
But by my back-of-the-envelope count, the deal the Obama administration has agreed to still leaves a net fiscal impetus of -1.75% of GDP to hit the U.S. economy in 2013. That is only 40% of the way back from the "austerity bomb" to where we want to be.
That isn't enough to make it worthwhile to make a deal before the new congress. After Boehner's reelection as Speaker and after the expiration of the Bush tax cuts eliminates the U.S.'s structural deficit, the politics become very different...
