Convention bumps are not a myth. Several nights of party messaging on several television channels really does change voter opinion. Tom Holbrook has the historic range of convention bumps:
Not only are convention bumps real, but they are also of very different sizes. There are two keys in determining the size of the bump, the first one apparently being to hold an early convention. While this might seem like an advantage for Obama, since both conventions are much later than normal, it is probably irrelevant. The other main factor in the size of the bump is how the candidates are performing relative to their expected vote share at the time of the convention. More from Holbrook (more in the extended entry):
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First, candidates who are running ahead of where they "should" be (based on the expected election outcome) tend to get smaller bumps, and those running behind their expected level of support get larger bumps. In this way, the conventions help bring the public closer to the expected outcome and help to make elections more predictable. The perfect example of this phenomenon is the 1964 conventions. Goldwater got a huge bump, in part because he was running 16 points behind his expected vote share, and Johnson got no bump, in part because he was running 6 points above his expected vote share. Likewise, Al Gore was running well behind his expected level of support in 2000 and got a substantial bump, while George W. Bush was running ahead of his expected level in the same year and received a rather modest bump.
In addition to being supported by the data, this makes intuitive sense. Due to the extensive national media attention they receive, conventions level the campaign out to a sort of "natural" state that temporarily wipes away the effects earlier campaigning. So, candidates who are performing above their heads, like Kerry in 2004 or Bush in 2000, tend to fall back to earth once the conventions are over.
Given this, the most important question heading into the convention is "who is currently overperforming?" The answer to this question isn't as easy as it might seem. On the one hand, Obama is scoring well under the current Democratic Party advantage in generic ballots and partisan favorability. As such, it must seem like McCain is currently over-performing and thus will receive a smaller convention bounce. However, on the other hand, Obama holds a 35-1 advantage in daily voter contacts, a more than 3-1 advantage in field offices, has a decent lead in paid media, and a significant advantage in free media. Also, it is entirely possible that his advantages in June were inflated as a result of the Democratic primary that for several months turned all attention away from McCain. So, Obama might actually the candidate who is currently over-performing, and McCain will receive the larger net convention bounce.
It is very difficult to not conclude that McCain is winning the messaging war right now. If Obama is winning in field, paid media, and free media exposure in a very Democratic year, what other explanation could there possibly be for his narrow lead nationally? It honestly scares the crap out of me that the Obama campaign will run another vacuous, "positive" campaign like Kerry's that simply does not attack and define the Republican nominee in a way that is necessary. If things do not go well in the next three weeks, McCain could enter the third week of September with a lead similar that the one currently held by Obama. If that happens, he will become the favorite, no matter how hard the Democratic winds are blowing.
With the destruction of the country looming, about the only positive in that situation will be that a certain segment of blogosphere commenters might finally consider the notions that Obama isn't exactly running the best campaign of all-time, and that not all of the progressives who critique his strategy are idiots who don't know what they are talking about. |
