John Armstrong: Peters prospects for gold in claims against Clarkson

It is another extraordinary twist in the ever-changing plot of this remarkable election that the result could yet hang on the words of one Vivienne d'Or, a name that could come straight from the pages of a romantic potboiler.

The credibility that Tauranga voters attach to the testimony of Ms d'Or, who stepped off Emirates flight 406 from Melbourne and into the election campaign yesterday, may not just determine whether Winston Peters survives as an MP or not.

Her allegations of sexual impropriety against Bob Clarkson, National's Tauranga candidate, may yet have a bearing on who governs after Saturday.

If Mr Peters loses in Tauranga and New Zealand First slips below the 5 per cent threshold and out of Parliament, National will have only United Future as a potential governing partner.

Given that party's low polling, National would have to secure at least 45 per cent of the vote to secure even the slimmest of majorities.

It is a tall order. No party has reached anywhere near that level in the three previous MMP elections.

National achieved it in 1975 and 1990. But that was under first-past-the-post - an electoral system that disadvantaged small parties. Those two elections were also landslides as voters moved to toss Labour out. That is not going to happen in this year's election.

For Mr Peters, the gamble is straightforward. He knows he will be seen as desperate. But he hopes that will be secondary to enough mud sticking to Mr Clarkson to sink him.

Mr Peters has a two-pronged strategy. He is not just trying to sow doubt in the minds of National voters about Mr Clarkson's suitability as an MP. He is trying to stop the Labour vote in his seat collapsing in Mr Clarkson's favour.

Mr Peters is clearly intent on making voting for the National candidate that much more difficult for Labour supporters to stomach.

The risk is his behaviour will rebound on him.

Mr Peters' appeal has long resided in his being the underdog. This time we are seeing a very different, very desperate political animal.

To make things more complicated, it is the perverse nature of MMP that it would suit National's wider interests for Mr Peters to beat Mr Clarkson.

Not that the party would say so. Or necessarily even agree.

Anyway, its hands are tied when it comes to helping Mr Peters. National can hardly be seen to give any nod of approval to NZ First while Mr Peters is ruthlessly bagging its candidate.

Nor can National do much to help NZ First beat the 5 per cent threshold. It could be counter-productive for National to do so.

In another quirk of this campaign, Mr Peters will talk support on confidence motions first with the party that wins most seats on Saturday night.

While it would not want NZ First falling below the threshold, National does not want NZ First to win too many seats at its expense which would then see National slipping behind Labour's tally.

The big question is how the allegations swirling around the Tauranga campaign have affected NZ First's already-slipping support.

In trying to dig the dirt on Mr Clarkson, Mr Peters may have been digging his own grave.