The Joe and Hillary show

Obama has taken a colossal risk in choosing the gaffe-prone Biden and may come to regret not opting

We have now reached the end of day two of the eight days of the 2008 Democratic and Republican conventions as I write - the Democrats reserved the Pepsi Centre in Denver for the first four and the Republicans the Xcel Energy Centre in St Paul, Minnesota, for the remaining four that begin on 1 September - and so far the roof has not fallen in over either party. Hillary Clinton was all kissy-kissy and exuding pro-Obama fire and brimstone when she spoke on Tuesday night, as I knew she would be: she has no intention of jeopardising her career as US senator for New York, or the good chance she believes she still has, should Barack Obama lose in November, of securing the Democratic presidential nomination in 2012.

It could be that, by the time you read this, her husband will have launched a kamikaze attack on Obama in his speech on Wednesday night - or Republican prayers might have been answered and a tornado will have struck the huge open-air football stadium that he immodestly chose to deliver his acceptance address the following evening (just as JFK did when he gave his acceptance speech from the Los Angeles Memorial Coliseum rather than the convention venue next door - geddit?).

But I doubt it very much. American political conventions become interesting only if things go wrong and fights break out; the Democrats' first two days were hardly organised like clockwork and sometimes deteriorated into a shambles, but that was merely business as usual. To sit through a day of one of these conventions is stupefyingly boring: although television coverage gives the reverse impression, almost none of the thousands on the convention floors listen to a word spoken by perhaps 95 per cent of the speakers, who nonetheless plough through their big moment as though the world were on tenterhooks.

For the remaining 5 per cent or so of speakers, it is the precise opposite. Each night at least one over-rehearsed, overprepared, over-coiffed and over-choreographed man or woman will dominate the proceedings with an autocued speech to which everyone (including a coast-to-coast television audience of 20 million) listens intently. Michelle Obama played that role competently on the Democrats' first night - but her performance suffered from the artificiality engendered by overpreparation (I wish the Obamas would stop using their daughters as props who supposedly spontaneously shout cute things to their mum and dad - fully miked and right on cue).

Meanwhile, the newly appointed Democratic vice-presidential candidate, Joe Biden, "choked up" when he spoke to delegates from his home state of Delaware - choking up being obligatory for all American politicians when the appropriate chance arises. Even what should have been a truly moving moment - surely the last appearance on a convention stage by Ted Kennedy - seemed choreographed and mawkish, alas.

The divisive issue never far from the surface in Denver, though, was Obama's choice for the vice-presidential slot of Biden rather than Hillary Clinton. Nobody should underestimate the depth of the fissures that started to divide the Democrats as soon as the 2008 primaries turned nasty and it became apparent that the Obama campaign was masterful in disguising its dirty tricks, and it will take a lot more than a gracious speech or two to heal the underlying wounds.

Rudy Giuliani, the former Republican mayor of New York, dropped by in Denver and said it was a "no-brainer" that Obama should have chosen Clinton, given that their primary season tussle ended in a virtual dead heat and that, in the end, more Democrats probably voted in the primaries for Clinton than for Obama himself. Clinton, too, always had stronger credentials for the general election in November: she was a consistently better performer in the crucial battleground states, and had cornered the votes of the poor working class and women.

An Obama-Clinton ticket would have meant overcoming deep personal animosities, but there is a tradition of presidential candidates and their running mates loathing each other: JFK and LBJ hardly spoke, and there was no love lost even between Ronald Reagan and George H W Bush. Biden can bring some of the pluses to the ticket that Clinton would have brought - getting out the working-class vote, perhaps - and may even be able to deliver the battleground state of Pennsylvania, where he grew up, to the Democrats.

But Obama is taking a colossal risk by passing over Clinton in favour of Biden, who is perhaps the most notorious and gaffe-prone windbag in the Senate; the Republicans are already rubbing their hands with gleeful anticipation. John McCain will have tried to steal some of Obama's thunder on Friday by naming his own running mate (possibly the former governor Mitt Romney, a McCain apparatchik tells me) and then the whole circus moves north to Minnesota.

The Republicans, I predict, will put on an al together slicker show than the Democrats - providing another timely reminder that they and McCain are still very much contenders in this most engrossing of presidential races.