ABC The Drum

Campaign folklore tells of many highly charged moments in US presidential debates, so will today's Republican primaries debate offer more gaffes and goodies? And who will come out as crowd favourite?

To the American political junkie there is something captivating about presidential candidate debates.

There always seems to be an electric current running through the room — a current comprised of absolute power, or potential power, and of knowing anything, anything could happen. One of these men or women could be about to go from mere mortal senator, governor or private citizen, into being the most powerful politician on the planet.

They may ascend to the pantheon of Washington, Lincoln and Roosevelt, and will literally hold the fate of the world in their hands — or at least within reach — an aide tends to carry the "football" with the nuclear codes.

Campaign folklore is full of such highly charged moments — the zingers, the gaffes, the curly questions — even something as innocuous as a look at a wrist watch or an audible sigh can take on huge meaning, a potential "game-changer".

There was that question from CNN's Bernard Shaw in 1988, when he asked Democrat Mike Dukakis if he'd support the death penalty if his wife Kitty were raped and murdered. The Duke's calm, matter-of-a-fact reiteration of his opposition to the death penalty seemed utterly heartless. The same year, his Democratic running mate Lloyd Bentsen slapped down future vice-president Dan Quayle by memorably telling him "you're no Jack Kennedy".

Ronald Reagan's good natured chiding of president Jimmy Carter's attempts at demonising him with a "there you go again..." charmed a nation. Jerry Ford's inexplicable denial that the Soviet Union dominated Eastern Europe in 1976 reinforced the view he was an accidental president bumbling his way out of the Oval Office.

More recently there was Barack Obama's irritable demeanour in his first debate with Mitt Romney in 2012 that vaulted his opponent into contention. Earlier in that campaign, Romney may have benefitted from two other rivals missing an opening or forgetting their lines: once when Tim Pawlenty wouldn't repeat his description of Obamacare as "Obamneycare" to Romney's face, and another when Rick Perry forgot which government agencies he'd promised to scrap. Oops.

Yes, with all of that in mind, it's easy to conclude these debates are decisive affairs. Yet you could just as easily argue in fact that most debates simply don't matter, and if anything, what matters is the way the media reports on the debate, not the debate itself.

For instance, straight after the debate when president Ford denied the Soviet Union dominated Eastern Europe, polls of people who watched the debate showed he had narrowly beaten Carter 44–43 per cent. But the following day, after the newspapers and TV reports zeroed in on the gaffe, Carter was declared the winner by 62 per cent to 17 per cent.

However, being declared the winner of a debate doesn't necessarily make you a winner at the ballot box. An analysis of data from the Gallup Poll shows the debates had no discernible impact on voter preferences for the major party candidates in 1980, 1984, 1988, 1992 and 1996.

The 1976 debates between Carter and Ford may have made the race more competitive, bringing Ford back into contention despite the Eastern Europe gaffe, but he still lost. And in 2004, Democrat John Kerry gained some ground against president George W. Bush, but Bush still won.

Gallup says it is possible that in the squeaker elections of 1960 and 2000 that the debates could have had a decisive effect. But in a squeaker you can also argue the weather has an effect. Nevertheless, it is true they are the only election that saw a candidate trailing before the debates move into the lead by election day.

So much for the impact of general election debates, what about primary debates involving a cattle call of candidates from one political party all vying to be the nominee?

Well, there, it appears, debates might actually matter.

Studies have found while only 3.5 per cent of viewers change their voting preference from one candidate to another in a general election debate, and only 2.4 per cent switch after a vice-presidential debate, in the primary debates 35.4 per cent switch their vote, and another 22.6 per cent go from being undecided to picking a preferred candidate.

So while Mike Dukakis flubbing his answer to Bernard Shaw may have had no effect, and Lloyd Bentsen's zinger to Dan Quayle probably did bubkis in terms of votes, Rick Perry's "oops" and Tim Pawlenty's baulk in 2011 may have nixed their chances of being the Republican nominee.

This article was originally published at ABC The Drum