John Armstrong: No margin for error as gap closes

In what is becoming the "margin-of-error election", there is no longer any margin for error.

The narrowing of the gap between Labour and National puts a premium on avoiding blunders as the voting intentions of a highly volatile electorate begin to firm over the final two weeks of the campaign.

The smart money would be on Labour keeping self-discipline ahead of the more accident-prone National.

The good news for National is that it has surged back into contention just at the right time.

The rolling average of the major polls has the party within three percentage points of Labour on the back of promised tax cuts and policy to end special treatment for Maori.

Two polls out this weekend may see that gap narrow even more - and even see National squeak ahead.

National will have definitely scored a major psychological victory if it is ahead in the influential One News-Colmar Brunton poll.

Whatever, there are two likely scenarios for the final run-up.

The first has National overtaking Labour - as it has at times since 2002 - only to again fail to sustain the advantage and slip behind again.

Although the party has moved mountains, the feeling lingers that National has not done quite enough to make the final push to the summit.

The second scenario has the two major parties neck-and-neck within the margin of error right to the line.

This two-horse race may be deemed less important when minor parties are crucial to who governs.

But with fewer potential coalition partners, National sees it as vital it wins more seats than Labour.

That would give it the "moral mandate" to argue it should have first option on forming a Government - even if Labour and the Greens had more seats combined.

It would put pressure on NZ First to back National - presuming NZ First is still in Parliament.

The possibility of Winston Peters losing his Tauranga seat and NZ First falling under the 5 per cent threshold is suddenly confronting National with some difficult choices.

Should Dr Brash nobble his own candidate to help Mr Peters by hinting to Tauranga voters that a National victory is not essential? Or is National better off ridding itself of Mr Peters for good?

Act could pose a similar quandary in Epsom, where Rodney Hide is relentlessly hounding National for a similar nod-wink endorsement.

So, what are you going to do, Dr Brash? There is no margin for error.