By Scott Lemieux
Last year, I discussed some political science research indicating that, contrary to past findings that vice presidential candidates have little effect on electoral outcomes, John McCain's selection of Sarah Palin actually had a significant (and, as it happens, negative) effect on his campaign. A new paper by Roy Ellis, D. Sunshine Hillygus, and Norman Nie also found using a different methodology that Palin's selection had an unusually significant effect on outcome of the 2008 election:
In this paper, we leverage a 10-wave election panel to examine the relative and dynamic effects of voter evaluations of Bush, Palin, Biden, McCain, and Obama in the 2008 presidential election. We show that the effects of these political figures on vote choice evolves through the campaign, with the predictive effects of President Bush declining after the nominees are known, and the effects of the candidates (and Palin), increasing towards Election Day. In evaluating the relative effects of these political figures on individual-level changes in vote choice during the fall campaign, we also find that evaluations of the candidates and Sarah Palin dwarf that of President Bush. Our results suggest a Bayesian model of voter decision making in which retrospective evaluations of the previous administration might provide a starting point for assessing the candidates, but prospective evaluations based on information learned during the campaign helps voters to update their candidate preference. Finally, we estimate the “Palin effect,” based on individual-level changes in favorability towards the vice-presidential nominee, and conclude that her campaign performance cost McCain just under 2% of the final vote share.The paper's other conclusions -- which suggest that the 2008 candidates had a larger effect on the outcome of the election than much past research has indicated -- is also worth reading. If Palin did have a negative effect, this is worth keeping in mind should she be the 2012 Republican nominee. It is also important, however, to remember that unless her effect as a presidential candidate was much larger Palin is definitely capable of winning a presidential election in the right circumstances. It is unusual for a presidential election to be decided by 2 points or fewer, so even relatively large candidate effects are usually swamped by more fundamental factors (such as the state of the economy.) It is also possible that some of Palin's negative impact as a presidential candidate, if it exists, could be mitigated by a greater ability to motivate the Republican base.