So far, Labour has tried still the same old Tory and chameleon Dave. Neither has gained any traction at all. Just as people could see that Mr Blair was plainly not same old Labour, they can see that Mr Cameron is genuinely different from Margaret Thatcher and the hapless trio who came after the dull but decent John Major. Just as the Conservatives lost all credibility when they produced a poster of Mr Blair with demonic eyes before the 1997 election, so Labour fails when it attempts to brand Mr Cameron as a Thatcherite wolf in sheep's clothing.
The chameleon jibe is just as hopeless. When New Labour made its peace with market economics, it also made itself electable. So what if Mr Cameron's passionate concern for environment appears to be of relatively recent origin Voters are unlikely to think less of him because his mind is open to the mounting evidence of climate change. Similarly, they are unlikely to punish Mr Cameron for abandoning the Tories' previous obsessions with things that most people are indifferent to, such as the inner workings of the European Union, in favour of things they do care about, such as the state of the health service.
Mr Blair, to his credit, was pretty sceptical about both those approaches. But he is very much the author of the latest attempt to cut Mr Cameron down to size. Last week Mr Blair declared that the next election will be a flyweight versus a heavyweight. He went on to say that no matter how much Mr Cameron might dance around the ring beforehand, at some point, he will come within the reach of a big clunking fist and, you know what, he will be out on his feet, carried out of the ring.
Although thrillingly effective in the gladiatorial arena of the House of Commons and, from Gordon Brown's point of view, a welcome endorsement of his leadership credentials, Mr Blair's imagery seemed less well-judged by the weekend. Mr Cameron had looked rattled at the time. But he and his team quickly realised that the picture conjured up by Mr Blair of Mr Brown lumbering after his more sprightly rival intent on smashing in his head, was a gift.
A poll by ICM in this week's Guardian suggests that when voters are asked to imagine Mr Brown going head-to-head with Mr Cameron, the Tory lead over Labour extends from five percentage points to eight. Earlier this month, a Populus poll in the Times showed where the Tory lead is coming from. Whereas men favour Labour under Mr Brown over the Cameron-led Tories by 37% to 34%, women split 42% to 30% the other way.
That Mr Brown relishes his bruiser image says something both about the way in which he conducts his politics and the difficulty he faces in winning back the swing voters who have deserted Labour for the herbivorous Liberal Democrats in the last few years and, more recently, for the Cameron-sanitised Tories.
Almost as problematic is the prime minister's depiction of Mr Cameron as a lightweight who peddles sunshine and hope without ever having taken a tough decision in his life. Although designed to contrast him not just with Mr Brown, but with the grizzled veteran Mr Blair has himself become, the truth is psychologically more complex. Mr Blair sees in Mr Cameron some of the callowness that he now despises in his earlier selfthat earlier self whose optimism and inexperience contributed to the frittering away of Labour's first years in office.
As it happens, despite the dearth of Tory policies, there is nothing insubstantial about the way in which Mr Cameron is preparing himself to take on Mr Brown. The largely successful first phase of his leadership, which was all about changing perceptions of the party, has begun to merge into the next. According to Oliver Letwin, who is in charge of policy co-ordination and much else besides, it is now time to move on to sharing with the electorate a thorough analysis of the condition of Britain. Mr Letwin says: In the past, if we brought forward a policy designed to improve the NHS, people would think our real aim was to kill it. Now when we talk about social justice, schools or the environment, they don't automatically dismiss it.
A Clause IV moment
On November 24th Mr Cameron was due to make a speech expected to endorse the message of a pamphlet published this week by the party's social justice policy group. One of its authors, Greg Clark, an up-and-coming MP close to Mr Cameron, writes: If the poorest people in this country fall too far behind those further up the income scale our society will fall apart. Such explicit recognition of the importance of relative poverty could become the Tory version of Labour's so-called Clause IV moment when Mr Blair persuaded his party to give up its historic commitment to nationalising things.
In an accompanying paper, Mr Clark produces a critique of Labour's anti-poverty policies, claiming that they have failed to help some of the poorest people in Britain. Subsequent reports will try to show how a Conservative government could do better. Mr Letwin says that this work, in common with that of the five other policy groups, will inform, but not dictate, the policies the shadow cabinet draws up for the election manifesto.
Until those policies emerge in late 2008, we won't know whether all the effort has been worth it. Compassionate conservatism could well turn out to be rather better at description and analysis than coming up with affordable remedies. But what is not in doubt is that Mr Cameron has committed his party to a serious and painstaking process. Lightweight it isn't.
The Economist Newspaper Limited 2006