There is the adage that to be a winner you must look like a winner, I wonder if this extends to talking like a winner or claiming you can win by a landslide? This is something that has been said by Obama's team, if not Barack himself, and is being widely reported across the world's media. But the question is will saying you will win by a landslide guarantee that victory. The contrast could not be more stark than between Obama and Conservative leader David Cameron. Every time I have seen him face the question of winning the next general election he plays down his poll standing. Although his could be argued to be a much more assured victory than that of Obama, albeit further away in time, he is cautious about saying anything. So who is the most sensible?

There is a danger with claiming victory before election day, events can scupper your chances anyway, but saying 'I will win' can have an impact on the result. While the Sun claimed victory in 1992, I wonder how much impact the Sheffield rally had? The celebratory event where Labour's Neil Kinnock and Roy Hattersley put on a US convention style event for their supporters. This was broadcast a week before the election, so what impact could it have had and why should Obama beware saying he will win by huge margins?

For your own voters it is demobilising. A campaigner needs every loyal supporter in the key geographic areas to turn out for them as if every vote is crucial. If there is a perception that the win is going to be a foregone conclusion, why trudge out on a cold night in Ohio or Worcester?

For the floating voters there are two potential effects. Firstly they may see it as a sign of arrogance and decide to 'burst his (or her) bubble'. Secondly they may act in the same way as the loyalists, and this depends much on their political leanings and their involvement in the contest.

But it is actually your opponents you have to beware most as they begin to consider life under a government led by Obama/Cameron etc and decide to try to prevent it. In the US the two-party system largely prevents a massive swing, however with the UK on the cusp of three-party politics and election deals previously having been struck between Labour and Liberal Democrat activists, the Conservatives do not want a combination of the supporters of both opposition parties campaigning against them.

So for Obama it may make him appear to be a winner, but it may also have a negative impact on the outcome for him. Cameron, on the other hand, is telling supporters he needs them while not appearing arrogant or complacent. Therefore, he is not saying to anyone that the contest is a foregone conclusion. Brown will of course help him all the way, as there is only one thing worse than saying you are guaranteed to win: saying you are guaranteed to lose. That is a self-fulfilling prophecy.