Sounds like a nightmare scenario to me. Witness market crashes and a continued descent into another recession. Best scenario is a split government imho.
What Obama needs is a supermajority of liberal democrats. The Ben Nelsons and Joe Liebermans are a reality of the party, but if we can get a bunch of Pelosis or Barney Franks, we’d actually be able to get some great legislation done.
It would certainly lay to rest the debate about whether or not a more left-oriented leadership would bankrupt the country or usher in an era of prosperity and joy. Then we’d know whether to burn the right-wingers at the stake or run to them begging for their leadership and forgiveness.
Revolutions are made of this.
And of course, standing amidst the ruins of our society, the Left would hang its collective head and announce to the world, “We’re sorry. Our philosophy and worldview were complete horseshit, and led to the destruction of a great nation. Forgive us for persuading you to vote for us.”
Certainly, the Right would be prepared to make the same shameful admission were they in power in that situation.
Seriously, though, what would provide an unequivocal verdict on which general philosophy produced the better outcome for society? The current unraveling of Europe seems to be producing a disquieting verdict on the viability of the modern welfare state. Disquieting to me, anyway, because while and where it has worked, people were undoubtedly happier than just about any other place and time.
If this scenario played out, I think there’d be a lot of cold people in hell and a bunch of flying bacon in the sky. 
But seriously, I’d just LOVE to see how the republican minority in both the house and the senate react.