KEY POINTS:
Peter Dunne's decision to suddenly swing his party's support in behind National and rule out a deal with Labour may have a rodents-and-sinking-ships feel about it.
But this is more a case of the United Future leader cunningly jumping the Labour ship before the ship's crew dump him overboard as surplus to requirements.
There was no great surprise at yesterday's announcement that United Future will back a National-led government. It was always assumed that Dunne would opt for National this time, partly because he could see which way the political wind was blowing.
Where he has shifted position is in specifically ruling out propping up a Labour-led government, at least after this election.
Dunne blamed "ideological barriers" for ending six years of co-operation with Labour in government, saying those barriers would only be entrenched further by the inevitable presence of the Greens in any new Labour-led government.
However, it is also likely Dunne realised he would not bring enough parliamentary seats to the post-election negotiating table to help Labour secure a majority.
The Greens, the Maori Party and NZ First (if it gets above the 5 per cent threshold) are all likely to win at least five or six seats against United Future's one on current polling.
Two of those other parties' votes plus Dunne's will probably not be enough to get a majority. All three parties' votes plus Dunne's may well be too much. That makes Dunne dispensable. Figuring therefore that he will be in Opposition if Labour wins, Dunne timed his approach to National with perfection.
John Key may well be getting mileage from claiming Labour will govern as one head of a "five-headed monster", but Labour at least has friends. National needs to eradicate the impression that it does not. Key needed to be seen shaking hands with another leader. Dunne fitted the bill.
In return, Dunne has Key's assurances that he will be a Cabinet minister in a National-led government, while National will give him an easy run in his Ohariu seat.
National is hoping Dunne's party might be under-represented in poll results.
Picking up two or three seats would be of considerable help for National to gain a majority.
Yesterday's announcement was thus also well-timed in raising Dunne's profile a day ahead of TVNZ's minor party leaders' debate.
Support for United Future famously surged in the final week of the 2002 campaign after Dunne impressed in such a debate.
The difference was that election witnessed National's support collapsing, leaving voters looking for an alternative.
Dunne was in the right place at the right time.
A repeat is unlikely. This time it is United Future's support that has collapsed - it is now below 1 per cent.
Still, Dunne's timing is still good enough to ensure the man labelled as Parliament's Quiet Achiever retains his other title of the Great Survivor.
