Among the numerous curiosities of the 2008 US presidential election campaign is the role reversal that has been executed by the two main parties.

Usually, when there is no incumbent president running for re-election (and even occasionally when there is) the Democrats, being a rowdy bunch, manage to produce an open, competitive race, a chaotic rolling maul of a contest from which a winner eventually emerges.

Republicans, meanwhile, are generally orderly and disciplined, dutifully falling into line behind a front-runner designated by their “establishment”, who gets into a brief knuckle fight with some upstart outsider and then cruises comfortably to the nomination.

This year it’s different. While the Democratic race is, as I noted last week, turning into an extended coronation for the Sun Queen, the Republican contest is a fog of competitive chaos. This is all the more striking because the polls suggest that the party is on course for a soaking next year on a scale not seen since the 1970s. Yet the number of plausible Republicans who want to be the party’s candidate is actually multiplying as they get closer to that election. It may, in fact, be the first known case in political history of rats auditioning to take the helm of a sinking ship.

This week the auditions moved to Michigan for yet another debate. An extra lectern – the ninth now – was required to accommodate the new candidate, the actor and former senator, Fred Thompson.

Mr Thompson has had an inauspicious start to his campaign since he launched it a month ago. His apparent diffidence and slightly detached approach have reinforced the central doubt that always hung over him – his work ethic, best captured perhaps by a famous Ronald Reagan quip: “Someone once told me hard work never killed anyone. But I figured, why take the risk?”

The effect has been to lower expectations for Mr Thompson so much that all he had to do this week was show up at the debate and not ask if he could lie down for a few minutes. In fact he was laconic and occasionally funny and navigated skilfully through the toughest question of the night – not about Iraq or fiscal policy, but: “Who is the leader of Canada?” “Harper,” he said, hesitantly. Then, visibly gaining in confidence, he beamed: “Prime Minister Harper.”

Mr Thompson’s encyclopedic display of North American political trivia helped to confirm his status as a relatively new front-runner. But the subset of candidates within the Republican field who are deemed to have a real chance has also got larger in other ways.

It is still led by Rudy Giuliani, the thrice-married Catholic who was Mayor of New York, and Mitt Romney, the monogamous Mormon from Massachusetts. Mr Giuliani leads in national polls, which may be meaningless, given that the first votes are cast in small, unrepresentative states, such as Iowa and New Hampshire, that can radically alter the rest of the election. Mr Romney leads in the polls in those early states, but they may matter less this time since the whole primary schedule has been tightly compressed into a few weeks early in the new year.

John McCain, who was written off for dead a few months ago when his money ran out, is showing signs of life, and cash, again. And into the top tier of candidates has climbed – almost – Mike Huckabee, the former Governor of Arkansas. Mr Huckabee, who looks a lot like Kevin Spacey but should be taken seriously nonetheless, is an engaging and thoughtful conservative, and has been climbing steadily, mostly through a clever stealth campaign in the farms and streets of Iowa. This week, as a poll put him in third place there, behind Mr Romney and Mr Thompson, he took some flak from an unexpected source.

It was revealed that Dan Bartlett, George Bush’s former communications chief, thinks that Mr Huckabee may be the best candidate, but won’t win because of his surname, which, he says, sounds too “hick”. This sounds like a piece of pure Waspish snobbery from a man named Bartlett, but if you think about it, there may be something to it.

Isn’t it likely, for example, that highly talented members of the current Congress such as Bart Stupak or Zach Wamp would have enjoyed rather more prominent national careers if they had been blessed with last names such as Bush or Clinton? (Of course, my daughter’s rabbit might have had a shot at a prominent political career if it had been called Bush or Clinton, but that’s another story.)

Hick or otherwise, Mr Huckabee can now be seen as yet another serious Republican contender, which is surely good news. While the Democrats sleepwalk their way behind the mesmeric but ultimately terrifying Mrs Clinton, the Republicans are exercising that most American of freedoms – a choice. And yet, for all this competition among candidates, there isn’t really much of a debate within the Republican Party.

There is a strong sense out there that American conservatism, and the Republican Party that houses it, is in a rare state of dysfunction. The dominion it has exercised over American politics for 30 years may be at an end. Out there, on the oped pages and the blogs and even in some state capitals, there is a genuine debate about what has gone wrong and what can be done to put it right.

What should a conservative foreign policy look like? What about the role and size of government? How much of a part should religious certainties play in the formulation of a secular social policy? But this lively discussion has not really reached the presidential debates. The main candidates seem eager to avoid challenging the prevailing conservative orthodoxies.

The Republicans seem oddly unhurried to change their party’s direction. Instead they seem to be staking everything on the assumption that, as unpopular as their party may be, voters will come flocking back when they start contemplating the imminent presidency of Hillary Clinton.

Every Republican, before he goes to bed at night, gets down on his knees and prays urgently for Mrs Clinton. This might be dangerously self-delusional and disastrously shortsighted. It might be an error of cataclysmic proportions that will condemn the Republican Party to many more years of public disapproval and internal division.

But then again, of course, it might be spot on.

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