A continuing theme I’ve been hearing on the political gabfests on cable news this week is that not only are the current polling numbers sketchy at best, they don’t really matter all that much because… wait until the debates! That seems to be the expected pivot point in the home stretch of the race, and analysts from both sides are playing the expectations game and declaring how vital it will be for Romney to “make his mark” or for Obama to “avoid a game changing slip-up.” But assuming that one of them doesn’t come out at the podium and announce that they are either a serial killer or that they’ve discovered a cure for cancer, (with proof) will the debates really move the needle for either of them?

Miranda Green thinks not.

A 2008 Gallup study found that between 1960 and 2004, there were only two years where debates made a difference in actual votes. Instead, the most common outcome of the presidential debates is a slight popularity bump. But that bump doesn’t necessarily translate into votes.

“They sometimes have a short-term effect, a bounce in response to the debates, but at the end of the day there often is not much of an effect,” says Robert Erikson, author of The Timeline of Presidential Elections.

Data from the Gallup study also saw no direct correlation between the winner of each debate and the winner of the presidency. The 2004 Kerry vs. Bush debate was cited as an example. Kerry was considered the victor of all three showdowns, but still lost the election.

Not to read too much into Ms. Green’s personal preferences here, but it seems to me that those who feel their preferred candidate is ahead (rightly or wrongly) might be more inclined to think the debates won’t matter. But even with that said, it seems to me as if there is still a strong possibility that these shows may not produce much in the way of heat. If the candidates have been coached to play it too safe to avoid any potential damage, we may be treated to nothing more than stilted reruns of portions of their stump speeches in response to questions.

But if either of them – perhaps more likely for Romney – feel like they need a breakout moment, they might take a more aggressive tack. There are already rumors flying about Mitt preparing some “zingers” for the President, leading to much amusement on Twitter over the weekend. That can go two ways, of course. If the delivery is off or it’s perceived as more mean than funny, off the mark, etc. then it could turn into a campaign advertisement which won’t help matters at all. But if he delivers something that comes off along the lines of, “I knew Jack Kennedy, and you, Senator, are no Jack Kennedy” then I still think the debates could light a fire at just the right time.

Will anyone be watching? This chart shows how TV audiences generally declined by media share for a quarter of a century after hitting a high water mark for Reagan vs Carter. But that trend turned around in 2008 with significant increases in viewership for Obama vs McCain, and the Republican primary debates scored well above expected levels. I continue to maintain my belief that summer numbers reflect mostly the “preaching to the choir” crowds, and there will always be a significant number of people who don’t watch news channels 24/7 and are yet open to seeing something unexpected which changes or makes up their mind in the final weeks.