In the French presidential elections, Fran?ois Hollande, the Socialist candidate, who advocates a 75 per cent marginal tax rate, is clearly on the left. But he has been threatened by an opponent further to the left: Jean-Luc Mélenchon, an ex-Trotskyite who has pledged to end globalisation and who trades on suspicions that Mr Hollande, like Fran?ois Mitterrand before him, will renege on his commitments. Nicolas Sarkozy, the sitting president, often gives the impression that he will say anything to retain office. Nevertheless, he can without abuse of language be described as to the right of these particular contenders.

Clearly there is a range of issues – and personalities – that it still makes sense to describe in left-versus-right terms. But there are many for which it does not. Is an interventionist foreign policy in the spirit of the late US Democrat senator Henry Jackson, designed to promote so-called democracy abroad, a leftwing or rightwing attitude? And what is one to say of Richard Cobden, the great English Liberal statesman, who wrote in 1847, “how much unnecessary solicitude and alarm England devotes to the affairs of foreign countries; with how little knowledge we enter upon the task of regulating the concerns of other people; and how much better we might employ our energies in improving matters at home”?

In some sense, both these men were centre-left. But such a classification covers huge differences more important to human welfare than the conventional left-right arguments on economic matters. I would instinctively prefer David Miliband to his brother Ed as leader of the UK Labour opposition; but my doubt is that he might be nearer to Jackson than to Cobden.