Mr Cameron's speech yesterday was typical of several delivered already and, I am told, an indicator of bigger speeches to come. He took as his theme the need to improve society's sense of well-being, describing it as the central challenge of our times. Like a strangely metamorphosed Bob Dylan, he declared: "We have to remember what makes people happy, as well as what makes stock markets rise."
As a result of such speeches, the new Conservative leader is attracting upbeat reviews from parts of the centre left. The head of the pressure group, Compass, Neal Lawson, described Mr Cameron's performance at a recent meeting on constitutional reform as "brilliant". Mr Lawson praised also Mr Cameron's attack on firms that target youngsters with adult clothes, despairing that Labour ministers would not dare to make the same point.
The chief executive of the Work Foundation, Will Hutton, notes that "Cameron has the persuasive capacity to double as politician and non-politician; audiences find themselves wanting to make common cause". Mr Cameron took part in a meeting at the Work Foundation on the work-life balance.
With a misjudged machismo, the new Home Secretary, John Reid, attacked Compass two weeks ago for being Old Labour. Meanwhile, Compass sees some virtues in Mr Cameron. In the mid- 1990s Mr Hutton was an influential figure in Blairite circles. Now he shows a degree of interest in the new Conservative leader.
This is not entirely surprising. Mr Cameron's technique is precisely the one applied by Mr Blair in the mid-1990s, but in reverse. Mr Blair went out of his way to woo business. With different dragons to slay, Mr Cameron warns that businesses could do more to enhance our sense of well-being. Yesterday he stated that: "If much of our modern globalised consumer culture ultimately seems unsatisfying, then it is because it fails to satisfy the deep human need to belong to someone and some place."
In advancing his case, Mr Cameron also deploys the familiar Blairite triangulation, in which two ill-defined extremes are described and the leader moves between them. The Conservative leader rejected those on the right who argue "we should leave it to the market and not interfere". At the same time he dismissed Gordon Brown's reliance on regulation. Those around Mr Cameron are very keen on establishing "dividing lines" with Mr Brown. How strange this is becoming. In the mid-1990s it was Mr Brown who pressed on Mr Blair the importance of dividing lines with the Conservatives.
But triangulation has its limits in terms of policymaking. In yesterday's artfully engaging speech, Mr Cameron was much better when speaking of his aspirations than explaining the means. I was reminded again of Mr Blair in the mid-1990s, even if the aspirations were more Bob Dylan in the 1960s. I still possess copies of Mr Blair's old speeches in which in the margins I had scrawled repeatedly a single word: How? Mr Blair proposed to modernise the constitution. The welfare state would be modernised too. Labour would lift standards in schools. Britain would be young again. How? How? How? How?
In retrospect, this was a dangerous period for Mr Blair. Some of his more deliberately evasive statements were hailed as profound philosophical insights. He discovered that his persuasive powers could mesmerise audiences even if the substance was sometimes flaky.
In his speech Mr Cameron attempted to answer the 'How' question. He wants to make the public sector the "world leader in progressive employment practice", a noble and ambitious goal. In addition, he seeks to use the power of the public platform as an advocate for progress. He will exhort rather than regulate.
But these solutions raise another thousand questions. The main one is highly charged and will take some answering. Where will the additional money come from to improve working conditions in the public sector? Senior Conservatives tell me that progressive employment will lead to efficiencies and save public money. In the longer term they are right. The evidence is overwhelming that employees are more productive when they are content. But, in the short term, making changes to improve the work-life balance in the public sector will be expensive.
Similarly, there are extreme limits to the power of public advocacy, as this government has discovered too many times. In his speech, Mr Cameron pointed to Jamie Oliver's impact on school dinners. Indeed Mr Oliver made the Government leap to attention. Yet the Government still had to leap. In some form or another the state had to find the cash to subsidise healthier dinners and to make sure the private companies delivered.
Exhortation is cheap, but never enough. To take two topical issues: We need cheaper train tickets and greater scope to take bikes on trains. This would be environmentally friendly and avoid the insanity of having to pay up to £200 to visit Manchester. More investment is required in Britain's antiquated water systems to move on from the surreal combination of incessant rain and a hosepipe ban. I cannot see improvements to either of these creaking industries that avoid higher public spending or more regulation.
Mr Cameron's speech therefore poses a challenge to his political opponents. They must make the case more confidently for an active, but benevolent state, pointing out that public spending and selective regulation can enhance the quality of life. Mr Cameron's clever soundbite that there is such a thing as a society, but it is not the same as the state, needs constant probing.
The Conservative leader is more serious about changing his party than some in the Government realise. I am told that in private informal meetings of Conservative MPs he is politely dismissive of traditional right- wingers when they raise concerns. Mr Cameron's course is set, but it is an uneven one that seeks progressive outcomes in the public arena while retaining an attachment to tax cuts and a smaller state. Or as Roy Jenkins once put it in relation to Mr Blair, he wants European-style public services and US levels of taxation.
Still, if Labour is too scared to put the case for a modern active state Mr Cameron will have fertile political space. Voters will assume they can look forward to a better quality of life without having to pay for it.