Beware the dangerous allure of the centre ground. Everyone wants to be there. Other leaders envy the great election winner, Tony Blair, for being seen as placed firmly on the centre of the political spectrum. Perceived as being to the left, Gordon Brown seeks to prove that he is on the centre too. David Cameron seeks to move there from the right. They dream of the day when they reach their destination, when the centre ground is theirs.
Dreams are deceptive. The apparently comforting terrain is nowhere near as safe as it seems. The centre ground is the equivalent of the beautiful woman in a "film noir", beguiling political leaders, teasing them, only to turn into a treacherous swamp once they have arrived.
One dreadful consequence of the overcrowded centre is a decline in interest in politics and in a commitment to political parties. On Tuesday, I argued that the media fuels a dangerous cynicism in politics. The nervy hugging of the centre ground is the other side of the equation. By blurring the differences, the party leaders invite an obvious question: What's the point of flying the flag for you lot when you are the same as the other lot?
Beneath the surface there are significant differences, almost as big as there have ever been. But time is short. People do not want to explore too deeply. Evidently, leaders do not want them to do so. If political leaders wanted to guide voters beneath the surface, they would take them there. Instead they gaze longingly towards the centre ground.
As a result, some Labour supporters despair. They have had to put up with Mr Blair's relationship with President Bush for several years. More recently, they have endured a government obsession with being seen to be tough on crime, new anti-terrorism measures and the renewal of Trident.
In addition, Gordon Brown has been set a test by the extreme Blairites: can he be a centre ground political leader, as defined by their hero? His main priority appears to be to prove that he can meet the test. Brown declared his support for Trident before Blair. Recently he wrote an article for The Sun hailing Blair's courage abroad and the primacy of the special relationship (note how Rupert Murdoch defines what it means to be on the centre ground). For now, Brown feels compelled to be more Blairite than Blair as he seeks the centre ground.
We must be extremely careful in reading too much into opinion polls at the moment, but no one can claim Labour's latest attempts to hug the centre ground are a rip-roaring success.
Not that this will stop Mr Cameron seeking to be in the same place as Blair, starting from the opposite direction. He speaks vividly on the environment, the causes of crime and the need for a less servile relationship with the US. The centre-left columnist Polly Toynbee is cited for her ideas on poverty.
His party twitches nervously in response. Derek Conway, the Conservative MP, warns of trouble ahead. When Mr Conway stirs there is need to take heed. In the early days of Iain Duncan Smith he told me with complete confidence the new leader would be ousted before very long. Soon IDS was gone.
The same fate does not await the more accomplished Cameron, but right-wing voters did not sign up to the Conservative Party to reflect on the causes of crime and the virtues of Ms Toynbee. At a summer by-election in a safe Conservative seat, quite a few of them did not turn up to vote. In these shapeless days, voters find means of registering their unease.
It is not only the voters that turn away. Odd things start to happen to those on the centre ground. Mr Blair has sought the approval of institutions that were alarmed by Labour in the 1980s. Yet his own centrist approach, such as seeking UN support for the invasion of Iraq but assuring Bush he would support the conflict if he failed, has rebounded on him.
The institutions that disapproved of Labour in the 1980s wring their hands once more. Army chiefs go public with their unease, an extraordinary state of affairs. Centre-left governments should never become too dependent on the Army. They do not understand the culture of the military. President Clinton was never entirely sure how to salute properly and practised the art privately. Bush has had many problems, but not that one. Now even the august Chatham House turns against Mr Blair's centrist foreign policies. Indeed, even the police turn on him with their deranged inquiry into cash for honours. At his most hyperactive, the left-wing Tony Benn never had the Army and police against him at the same time. Look what the centre ground can do.
In the end it offers no clear guidance as to where you are. Mr Blair has a clear sense of what he wants to do with power now. Sometimes his sense is too clear. But at the start of his second term he failed to recognise the need for investment in public services while his advisers, more rooted on the centre left, sniffed the urgency of the situation immediately.
Moving forward and rightwards, the current review of Conservative policies takes place in something of an ideological vacuum. Admirably, Mr Cameron has given his colleagues the freedom to range widely. But where do they range to and from?
Mr Blair once observed to me that while Conservative governments could rule from the centre right, Labour could rule only from the centre. In other words, Mr Blair believes that Britain tilts rightwards as a country. I sense this is the view of most ministers who cling nervously to power, regarding themselves as aberrant impostors in a Conservative land. But here is the twist. Recently a senior member of the shadow cabinet moaned that Britain was essentially a socialist country, and that the Conservatives had to adapt accordingly. He pointed out that in some parts of the country the vast majority of people are employed by the public sector.
He pointed also to the persistent high level of support for the NHS. He wanted to argue for more tax cuts now, and yet they did not seem popular. Out of power for a decade, with an ageing membership, the Conservatives fear they are toiling in a left-wing land.
The answer to the centre-ground conundrum is obvious in theory, but much harder to achieve in practice. Clinging to the centre is not enough. Parties need to achieve a synthesis that reassures doubters, while inspiring those that come from their part of the political spectrum. Labour managed it partially in 1997. Brown and Cameron must try now.
In the meantime, the parties suffer from bizarre identity crises. Labour leads a country it believes to be Conservative. The Conservatives seek power in what they regard to be a socialist land.