How Will the Democratic Superdelegates Vote?

This seems to be the question of the moment, as it is becoming increasingly likely that neither Obama nor Clinton will be able to win the nomination without the superdelegates playing a role. Many of the superdelegates have already pledged their support to either Clinton or Obama, but a majority of them have not committed to either candidate.

Given that the superdelegates may be decisive, it becomes an interesting exercise to try to understand which candidate they are likely to support. Therefore, we have been collecting some data on the superdelegates that we believe will provide some insight into whether they are likely to support Clinton or Obama.

Of course, predicting how a person might vote is quite error-prone, but politicians are often a bit more predictable because they have constituencies that they are accountable to if they want to keep their jobs. In other words, the stakes can be high for them, and their decision to back Obama or Clinton have ramifications for their reelection prospects or ability to raise money down the road.

We are in the process of putting together the data for all superdelegates, but we have already completed the data collection for members of the House, senators, and governors. According to our figures, there are 316 superdelegates that match this description. However, we did not have complete data for the House delegates/governors from DC and the territories, so we dropped those 5 members from our analysis.

We also remove every delegate from IL, NY, and AR from our analysis since these delegations are almost unanimously supporting the candidates from their states. (Every one of these delegates from NY and AR has already backed Clinton and all but one in IL has backed Obama.)

Essentially, we are using information about the superdelegates who have pledged their support for a candidate to try to predict how the unpledged superdelegates might go. Our model includes information about whether the delegate is black, hispanic, or female. It also includes the percent who voted for Bush in 2004 in that delegate's state or congressional district. In addition, we have information about the percentage of the population in the delegate's state that has a college degree, that belongs to a union, and that lives in an urban area, since these have all been factors affecting whether states have supported Obama or Clinton. Finally, we account for the per capita income in the delegate's state as well as whether the delegate comes from a southern state. Based on these factors, we were able to correctly predict 73.5% of the superdelegates who have already endorsed (not including those we excluded from IL, NY, AR, DC, and the territories).

There are many reasons to be cautious about these estimates. First, many superdelegates pledged their support long ago, and the factors affecting who a superdelegate was going to support in 2007 may be less relevant in 2008. Second, our model cannot really account for individualistic reasons that a superdelegate may support Obama or Clinton. In other words, we don't know who snubbed who in the hallways of the Capitol building or whether a candidate made a specific pledge or promise to a superdelegate.

We will wait until we have added all of the DNC members to our analysis before we give any firm estimates on how many superdelegates each candidate might receive. However, based on the analysis so far, here are the 10 office-holding superdelegates most likely to support each candidate:

10 Unpledged House Members/Senators/Governors Most Likely to Support Obama:
Dennis Moore, KS, House
Dave Freudenthal, WY, Governor
Rep. Stephanie Herseth Sandlin, SD, House
Mark Udall, CO, House
John Lynch, NH, Governor
Tom Allen, ME, House
Byron Dorgan, ND, Senator
Brian Schweitzer, MT, Governor
John Tester, MT, Senator
Max Baucus, MT, Senator

10 Unpledged House Members/Senators/Governors Most Likely to Support Clinton:
Ciro Rodriguez, TX, House
Susan Davis, CA, House
Marcia Kaptur, OH, House
Kathy Castor, FL, House
Lois Capps, CA, House
Betty Sutton, OH, House
Barbara Boxer, CA, Senator
Carl Levin, MI, Senator
Mary Landrieu, LA, Senator
Rep. Bart Stupak, MI, House

One last note: one factor we'd love to include is whether the superdelegate's state went for Clinton or Obama. However, the problem with trying to include that factor is that we don't know how nearly half of the states are going to vote yet, so if we incorporated that we would lose the ability to predict how superdelegates in those states might vote. However, many of the factors we include in the model (union population, education, income, vote for Bush) are meant to capture the propensity of a superdelegate's state to support Clinton or Obama.

Thanks to Alicia Prevost and Caitlin Zook for their help with this.