I've been out in the US all this past week, not to cover the elections, but to do a bit of research and casting for a film I'm working on about the 'special relationship' we all like to think we have with America. (We don't; they all think we have bad teeth and eat terrible food.) But it's impossible not to avoid the election and, in particular, how amazingly wrong pollsters and pundits have been about everyone's prospects. Last week, Obama did better than everyone thought, apart from in those states where he did less well than everyone thought. These were states where Clinton did better than anyone, including Clinton, thought. Meanwhile, for the Republicans, there was an unexpected comeback for Huckabee, whom so many people had stopped thinking about that it wasn't even possible to come up with a completely wrong prediction of how he would do.

In fact, each candidate is performing so unexpectedly that most of the TV networks are factoring in an automatic Unexpectedness Quotient with their polling estimates. This basically involves asking the voting intentions of as wide a sample as possible, in as much detail as possible, throwing this information away and then coming up with a figure at random.

The bigger networks have poured billions of dollars into software that scientifically calculates the one answer no one expected to hear. Plans are also underway for the actual election in November to do away with traditional voting machines and replace them with ones in which you pull a lever and a coin comes out that you're asked to toss.

Cogito, ergo... um

All this affirms the golden rule of life which is No One Knows Anything. This is particularly true in politics. (To confirm this, just listen to any 15 seconds of a speech by Mitt Romney.) We expect our politicians to have a brain full of conclusions and condemn them if they flip, hesitate, evade or ambiguate. We want them to be know-it-alls, even if that means we then condemn them for being smug.

But no one has yet done a study of how much human error or personal insecurity has played in the great movements of history. I met someone last week who told me that even Henry Kissinger, for the first three or four years working for Richard Nixon, went round asking people: 'D'you think he likes me? Does he think I'm doing a good job?' It's a sobering thought that the bombing of Cambodia could have been just an employee trying to impress his boss.

This came home to me more recently with revelations from Jack Straw in a recent interview about events leading up to the invasion of Iraq. He claimed that Tony Blair had set out with an intention to rein in George W Bush and to get his administration to plan properly for the after-effects of an invasion.

The reason this didn't happen was that the British went in thinking they had all bases covered; Blair would deal with Bush, Straw with Colin Powell and Geoff Hoon with Donald Rumsfeld. It would be a three-pronged attack. The only problem? The Americans had a fourth prong: Dick Cheney. He proved the most influential prong of all and the Brits had forgotten to bring a counterpart to deal with him.

There is probably a vast library of history books to be written on how a catastrophic military venture, costing hundreds of thousands of lives, international instability, mass terrorism and economic downturn, could have been averted by John Prescott.

I overturn an empire. Almost

The extension of the rule No One Knows Anything is the one that goes And Therefore Everything's Just Rubbish. An appreciation of the haunting truth of this came fully to me earlier where, at the heart of government of the most powerful nation on Earth, one under attack and pouring billions into homeland security, I managed to walk into the US State Department building and snoop around unhampered, getting in with nothing more than an amateurishly photocopied pass with the words BBC on it and a stupid photo of my face.

On the quiet advice of a Washington journalist, I wandered up to the security officer at the entrance to the State Department and said: 'BBC. I'm here for the 12.30.' I expected to be frisked, scooped out internally and asked to walk around wearing only seethrough clothes, but instead all I got was a 'sure' and total access to the nerve centre of the American empire.

I wandered around taking photos on my mobile and when anyone big approached with a 'what the hell do you think you're doing?' look on their faces, I nervously repeated: 'I'm here for the 12.30.' They just smiled and said: 'Oh, right. It's over there.' And so I carried on.

Part of me thought it was fun, but another part thought that technically this was international espionage. This was either a hot story or something that would end in me being water-boarded. So, in the end, I dutifully went to the 12.30. It was dull. It would have been more interesting if I'd stabbed Condoleezza Rice in the eye with my pen, which I could have done. I chose not to do this because that would have been unpleasant for all concerned and I had a new shirt. But if I had, imagine how the course of world politics could have been changed. As it is, I'm up there with Prescott as one of the non-giants of history.

Hello. Oh, goodbye

Final confirmation last week that Everything's Just Rubbish came from what everyone told me was the highly efficient Clinton campaign machine. Polls are about to take place in Virginia and Maryland, so her campaign team arranged for automatic telephone calls to every voter containing a message from her beginning 'Hi, Maryland' or 'Hi, Virginia' and urging them to get out and vote. Unfortunately, someone pressed the wrong button and every elector in Virginia got 'Hi, Maryland' and every Marylander got 'Hi, Virginia'. Expect her to do badly this week.