As an independent, I am a fan of divided government. Since Democrats have lately been doing better in their Senate races, while the Republicans are quite unlikely to lose the House of Representatives, there is an excellent chance that the winner in the presidential election will not have a majority in both houses of Congress. Brian Beutler somewhat overstates the case that divided government will win in his post "Why the GOP Agenda is Likely Dead Even If Romney Wins." Mitt is more likely to win in a situation where the Republicans also do will in their Senate races, than in a situation in which the Democrats hold the Senate. So the folks betting on Intrade are today giving an 18.4% chance that Mitt will win along with the Republicans getting both houses of Congress, while Mitt has a 13.8% chance of winning but facing a Democratic Senate, and quite small chances of winning but facing a Democratic House. (Mitt’s overall probability of winning is 33% according to Intrade.) So conditional on Mitt winning, Intrade suggests he is more likely than not to have both houses of Congress with him, but there is a substantial chance he will be checked by a Democratic Senate.
On the other side, Intrade gives only a 2% chance that Obama will be elected along with both houses of Congress being in Democratic hands. So an Obama victory has a very high chance of also being a victory for divided government. Overall, Intrade gives divided government an 80% chance of winning, with the bulk of the 20% chance of divided government losing falling on Mitt’s side.
Let me make the prediction that, even if Mitt wins the presidency and the Republicans win the Senate as well as the House, Republican control of both houses of Congress would last no more than two years. The President’s party often loses seats at the first midterm election— and the Republicans seem eager to try enough bitter medicine for the body politic—that I suspect an all-Republican government would suffer somewhat larger than usual losses at the elections in 2014.
What all this boils down to is that anyone who fears truly extreme results from the presidential election is unlikely to see those fears realized. We are likely to continue to experience the blessings of divided government bestowed upon us abundantly by the framers of the Constitution through their ingenious design of checks and balances.