Impact of the second presidential debate on the election.

To understand the influence of the second Presidential debate tonight, we should begin by assessing the impact of the first debate on October 3.

1. Mitt Romney was declared the winner of the first debate by the media and seemingly by public opinion. This win improved Romney's national polling averages by at least 3%. At the same time, Obama has lost about 2%. Inspection of the Pew poll taken after the debate reveals that the movements were largely a consequence of a flip of enthusiasm, with Obama's supporters losing enthusiasm while Romney supporters gained it. These changes in the polls resulted in Romney's ultimately enjoying about a 1.5% lead in national polling among likely voters. But it is important to note that the swing didn't come principally from undecided voters but from voters who already have an allegiance to their candidates.
2. Stylistically, Romney gave a solid performance in the first debate while Obama was somewhat lackluster, probably in an attempt to avoid confrontation which might have alienated undecided voters. While Romney's better stylistic performance helped him significantly in the polls, it also burdened Romney with higher expectations in the second debate. In other words, he had few Republican voters to motivate in the second debate because they were already motivated.

Thanks to these points, it is not necessary to declare a winner to predict how tonight's debate affects the general election. Instead, I only have to estimate how each candidate's performance is perceived by his own supporters.

First, both candidates had solid performances, with the only noticeable stumble coming from Mitt Romney, who appeared to misunderstand the content of Obama's statements in the aftermath of the Benghazi attacks. Given that Romney's performance tonight was no stronger than his previous performance, it is unlikely that he gained any support that he didn't already have. The Benghazi stumble rattled Romney a little, but was not catastrophic in the eyes of his supporters. So it is unlikely that Romney will see much of a drop in the polls in the wake of tonight's performance.

Second, Obama was on attack and he hit every key talking point, like Romney's "47%" comments and some of Romney's stated positions on women's issues. While Obama's attack strategy may not guarantee his gaining of many undecided voters, it is very likely that he did charge up his own supporters. For example, the NPR snap poll, which has a strong liberal bias, had the President winning tonight's debate 90% to 10%. This poll indicates that Obama overwhelming pleased his supporters tonight. Consider that the NPR snap poll after the first debate gave Romney a slight advantage.

With these observations in mind, it's straightforward to predict how tonight's debate will influence the polling and consequently our expectations for the general election: Obama should gain the 2% back that he lost after the last debate plus about 0.5% that Romney will lose for (1) his stumble over Benghazi and (2) for Obama's serendipitously getting the last word and using it to jab Romney with reminders of the "47%" comments.

This predicted 2.5% swing in the poll numbers will likely solidify both Pennsylvania and Ohio for Obama and push both Colorado and Virginia to lean towards Obama over the next week. Florida may even come back into play.

Chances for Victory Update

Here are the Chances for Victory if the election were held on 10/17/12:

• Obama - 96.9% (290 Electoral College votes most likely)
• Romney - 3.1%