Rupert Cornwell: No one's giving thanks for this debate marathon

Yes, it's Thanksgiving week. Which means turkey and cranberry sauce, visits from in-laws you can just about put up with once a year, a televised NFL game featuring the Detroit Lions – and this year, it goes without saying, a Republican presidential candidates' debate. Or rather two of them.

They were at it last night in Iowa, and Mitt Romney, Newt Gingrich, Herman Cain, Rick Perry and the gang will be at it again on Tuesday evening, a political hors d'oeuvre ahead of the real gastronomic event on Thursday. Alas, to paraphrase Winston Churchill (who wouldn't have been seen dead at one of these events), never have the same small group of individuals gathered so often to impart so little.

This is not to suggest that American presidential primary debates should be scrapped. On the contrary, they offer candidates a wide public platform, allow issues to be aired and give voters the chance to assess the individuals seeking the most powerful and most gruelling job on earth. But matters are now surely out of hand.

Believe it or not, primary debates have been around even longer than presidential debates proper. A dozen years before John Kennedy and Richard Nixon first did battle on TV in 1960, Thomas Dewey and Harold Stassen held a radio debate for the 1948 Republican nomination to face Harry Truman, and the Democrats did likewise in 1956. By the Eighties, primary debates had become part of the landscape, and in 2008 the Democrats held no fewer than 19 – an excess perhaps excusable given the calibre of the field and the protracted struggle between Barack Obama and Hillary Clinton.

Now even Republicans wouldn't pretend their 2012 crop of candidates is a stand-out. This time around, though, 25 debates have been scheduled. We've already had 12, Saturday's was No 13 and Tuesday will see the 14th. By then participants will have more than earned their turkey and trimmings. But they'll be back in action for three more debates inside 10 days in mid-December, shortly before the Iowa caucuses that kick off the primary season.

The last of the 25 is set for 19 March in Portland, Oregon. But if a winner has still not emerged by then, you can bet there'll be more. And why not? The 2012 debates have proved an unexpected prime-time hit, pushing up ratings and ad revenues for the networks and cable channels that sponsor them.

And while the TV companies get virtually free programming, the politicians get free exposure. Fringe candidates can stay in the race, even though they're statistical margins of error in the polls, and otherwise lack the organisational and cash resources to mount a proper campaign. In short, the plethora of debates suits everyone. Except, I would argue, the Republican party, and its chances of regaining the White House.

One problem is the nature of the show. Candidates are obliged to tack to the right, with applause lines that are tailored to win the activist-dominated primaries but which aren't so great for a general election that will be decided by moderates and independent voters. The more numerous the debates, the greater the chance the eventual winner will say or do something that, come September, is fodder for the Obama campaign.

Not surprisingly some candidates have suggested they might skip a few, if only to conserve their energy. But if you are Rick Perry, you are instantly accused of wimping out, to spare yourself further embarrassment in a forum where you don't shine. Rightly, debates reward people who can think on their feet and express themselves clearly, but those are far from the only qualities required to run the country.

Then there's the format. These "debates" are not really debates at all, rather a series of 30-second or one-minute responses to questions from moderators, followed by a limited exchange between one or two candidates. Fair enough, since the alternative would be a free-for-all shouting match. But do not expect serious, developed argument. The person with the best one-liners wins.

What you're left with is politics-cum-reality TV, with a travelling troupe of familiar characters: Smooth Mitt, Hyperbolic Newt, Breezy Herman, Hulk Rick (Perry), Combative Rick (Santorum) and the rest. Reporters and audience crave above all a mega-gaffe, like Perry's failure to remember the three government departments he would strike from the face of the earth, or Cain's contention that the Taliban are helping to run Libya. But unlike on The Weakest Link, no contestant is asked to leave the show.

Debates are like diplomatic summits: the smaller the number of participants, the more productive they are. In past years, there were fewer debates, usually later in the primary season, and featuring fewer candidates after the also-rans had dropped out. As a result, genuine emotion surfaced. You could taste John McCain's visceral dislike of George W Bush in 2000, or Bill Clinton's anger in 1992 when Jerry Brown, his last remaining primary opponent, dragged Hillary into the argument.

But this year, conceivably, the primary debate marathon could be just the start. After Michele Bachmann, Perry and Cain, Gingrich has emerged as the latest "Anyone-But-Romney" candidate. Undisciplined, bombastic and eternally convinced of his own brilliance, our Newt carries enough political and personal baggage to fill a couple of freight trains. Most probably, his challenge will fade. But in this strange political year, who knows? And if he does become the Republicans' standard-bearer, then a nightmare scenario could unfold.

Once nominated, Gingrich says, he will challenge Obama to a series of debates, identical in format to the seven between William Douglas, the incumbent US senator from Illinois, and his challenger Abraham Lincoln in 1858. Dealing with momentous issues such as slavery and states' rights, these latter are part of the American political canon, studied and quoted to this day.

The good news is, they were one-on-one, with no moderator or also-rans cluttering the stage. The bad thing is their structure: a one-hour speech by one candidate, followed by a 90-minute response by his opponent, and then a 30-minute rebuttal by the first speaker. In other words, seven three-hour debates between Obama and Gingrich. That prospect alone should have all right-minded Republicans closing ranks behind smooth, but distrusted, Mitt. Happy Thanksgiving.