RHETORIC Friends, Romans, modernisers!

Rhetoric was invented in Greece in the 5th century BC, immediately after the foundation of democracy, to make persuasive public speaking available to all. If every free, male Athenian were to play his part in governing the city, he needed to command the language of politics - rhetoric, of which oratory is the practice - to bring others round to his viewpoint. The two concepts - rhetoric and democracy - are intertwined and interdependent. The citizen who could not express his opinions in the language of peaceful persuasion would lack the skill to take part in the democratic decision- making process and might as well hand the job over to a small, undemocratic lite: the oligarchy. Which would be fine, except that oligarchies can often be corrupted into dictatorships.

Rhetoric therefore has more than just a declamatory function. Leaving aside its content, how does the new version of Clause IV stand up to scrutiny according to the rules of rhetoric, as laid down by Aristotle?

Those rules have hardly changed at all, as a glance at any great statement of political intent will show. First, rhetoric loves the rule of three: "Life, liberty and the pursuit of happiness"; "Friends, Romans, countrymen!"; or, in the new Clause IV, "where we live together freely, in a spirit of solidarity, tolerance and respect". Same rule: but one of these lists is less effective than the others. The reason is that Jefferson, Franklin and Shakespeare understood, as the Labour Party's modern drafters have not, that each word must be longer than its predecessor. If Clause IV had said "respect, tolerance and solidarity" its resonance and climactic effect would have been improved.

The next rule of rhetoric is the use of balance and contrast. "Out of the strong came forth sweetness"; "from darkness we shall walk into light" - these are classic rhetorical contrasts. The new Clause IV has "... a just society, which judges its strength by the condition of the weak as much as the strong". It also offers the philosophically dubious "where the rights we enjoy reflect the duties we owe" as an example of contrast - no doubt hoping by the fluency of the phrase to deflect attention from whether it is true.

If metaphor can be introduced as well, so much the better. The new Clause IV is noticeably short on metaphor, unlike the old one which relied in its opening words on one of the richest and most biblical of metaphors: the idea of the fruits of one's labours. A "dynamic" economy has become such a clich that its metaphorical origins - the dynamo being a device that fires up the economy - have been lost. The same is true of "the market", now just a synonym for "competition".

The middle section talks, significantly, about "nurturing" families, using the imagery of devoted parenthood to describe the party's attitude to family and domestic life. Later in the same sentence is a reference to "delivering" people, in an image of godlike intervention, from the tyranny of "poverty, prejudice and the abuse of power" - a rule of three which this time gets its crescendo right.

The final rhetorical device is one which the Greeks called anaphora: the use of a repeated or onomatopoeic phrase or even just an opening word to hammer home the weight and importance of the ideas that follow. Thus, "for each of us" precedes "for all of us" to emphasise the contrast between the individual and the many. Later on it is used again: "a community in which power, wealth and opportunity [the list of three] are in the hands of the many, not the few [contrast]; where the rights we enjoy reflect the duties we owe [contrast and metaphor], and where we live together freely [anaphora] ..."

This analysis of Clause IV does not diminish it or imply that it is all style and no substance, but demonstrates how very little the rules of political speech have changed in 2,500 years.