Analysis of Presidential and Senate races gives a current long-term outlook for divided government at 34% probability, 1 in 3. Including the House would make the likelihood even higher. A House prediction will come tomorrow.
First, here is a histogram of Senate outcomes given current polls and a shift of up to +/-3% (uniform distribution) between now and November.
From this histogram, Democrats will retain Senate control with 65% probability, an uptick from my previous estimate of 52%, mainly because of Rep. Akin (R-MO)’s comments on “legitimate rape.” The probability estimate is very rough. Anything between 20% and 80% should be considered a knife edge.
What are the likeliest outcomes? Cases in which President Obama is re-elected are easier to estimate because his current November win probability as 88%. This covers most possible futures, and control of the Senate will be largely a statistically independent event from an Obama re-election.
This leads to the following scenarios, in descending order of likelihood.
Scenario 1: President Obama and a Democratic Senate: 57%. Under current rules requiring 60 votes for many actions, the Senate would be nearly paralyzed. However, Majority Leader Harry Reid has said that reforming the filibuster is a priority for him in the new Congress.
Scenario 2: President Obama and a Republican Senate: 31%. Reid said he’d also be in favor of filibuster reform in this case too. He’d have little say in the matter, though, and no good argument for opposing whatever the new majority wants. Although Obama has recently said that Republicans would be more likely to play ball once he’s re-elected, I am having trouble imagining that. I am having an easier time imagining continued polarization. Could be nasty.
The remaining options involve Romney winning the election. This would require a swing of at least 2.0% from current conditions. It would almost certainly be a close election, despite a silly model from a remote ivory tower.
Scenario 3: President Romney and a Republican Senate: 9%. In this case, Majority Leader McConnell would be under heavy pressure to do away with the filibuster. We would see lots of action, that’s for sure: repeal of Obamacare, continued tax cuts across the board.
Scenario 4: President Romney and a Democratic Senate: 3%. For similar reasons as Scenario 3, I think interest in reforming the filibuster would be greatly reduced.
Scenarios 2 and 4 make a total probability of 34%, or 1 in 3.
And…if Republicans retain the House, that is yet another possible path to divided government.
It appears near-certain that the Republicans will lose House seats. But how many? That is a murky question. Current signs indicate that one party has a slight edge in gaining/retaining control. But which one? I’ll post that tomorrow.