The past few days have been a strange experience for Charles Kennedy. As first highlighted in The Times, his attempts to quash rumours about his leadership merely increased the speculation. By yesterday he had to endure senior colleagues such as Sir Menzies Campbell, Simon Hughes and Mark Oaten appearing on various media outlets to offer highly qualified endorsements of him, coupled with a shameless willingness to seek his position in the event of a vacancy. With friends like these, Mr Kennedy might ask, who needs enemies in politics?

David Cameron has decided that this is the moment to persuade Liberal Democrats that he is now their friend and not their enemy. In an address in Hereford he made a pitch for supporters of Mr Kennedy’s party to switch to him and implied that a Conservative-Lib Dem pact was not implausible. He insisted that he was a “liberal conservative” and that “today we have a Conservative Party that believes passionately in green politics, that is committed to decentralisation and localism, that supports open markets and that is prepared to stand up for civil liberties and the rule of law, and wants Britain to be a positive participant in the EU as a champion of liberal values”.

It may not only be the left-leaning in the Liberal Democrats scratching their heads at this initiative. It would be understandable if Mr Cameron were to target the modernising or “Orange Book” tendency among Mr Kennedy’s MPs by contending that he too stood for market liberalism with a serious social conscience. This would be shrewd politics. His call yesterday, however, went much farther. It was aimed at a strain of Liberal Democrat sentiment which, on the whole, remains left-of-centre in inclination. Such people will be bemused and confused by the notion that a new Conservative Party intends to be a branch of Friends of the Earth.

This might all be entertaining in the short term but it makes for a strange longer-term strategy. The green pressure groups (and Liberal Democrats) whose approval the Tories appear to crave are not just looking for a commitment from the Leader of the Opposition to bicycle each day to work in Westminster. They want a dogmatic rejection of nuclear power. A sensible politician of the Centre or Centre Right should support that source of energy. The localism which other lobbies favour is of a scale that would make it impossible for Conservatives to introduce substantial market-orientated reforms of the public services.

Political opportunism is not without its price. It could allow a government led by Gordon Brown to present itself as a sober administration, prepared to make hard choices, pitted against an opposition that preferred inoffensive soft options. The Tories risk moving from being the “nasty party” to the “nothing party” — which is not much better. Mr Cameron probably is a “liberal conservative”, so there is no harm in him employing that language. He should not, though, leave the impression of being more liberal than conservative; he certainly does seem to be something of a political tart.