Patrick Gower: 'Jacinda Ardern effect' made Dunne dead in the water

OPINION: Peter Dunne has quit because he knew he was dead in the water - he was going to lose Ōhāriu to Labour.

Dunne was a political cockroach - it seemed nothing could kill him off. But the "Ardern effect" has finally done it. Polls showing Labour up in the electorate since Jacinda Ardern took over has finished Dunne off.

His release saying there is "a mood for change" is not-so-subtle code for "Ardern has changed things". 

Dunne has seen the writing on the wall: he could go the easy way and quit - or the hard way and lose after campaigning.

The worry for National is that Ōhāriu is a bellwether seat - and voters have swung from National to Labour.

Dunne has no doubt had access to National's internal polling which would show similar or worse to the recent TVNZ/Colmar Brunton poll which had Labour's Greg O'Connor on 48 percent, Dunne on 34 percent and Brett Hudson on 14 percent.

The poll shows a significant change in voter behaviour in Ōhāriu. Going on last election's party vote, Ōhāriu should be a National seat - it got 18,810 party votes, while Labour got 8,771. The poll shows this preference has since swung hugely in Labour's favour.

Like a lot of Wellington, the 'Ardern effect' is quite palpable in "upper-middle class" Ōhāriu, and that will no doubt be helping O'Connor despite the fact the former cop is a very incongruous fit with brand Ardern.

The poll showed that even if the Dunne/National vote was combined it was still even.

Dunne was never going to win with the vote split. There was some talk of National pulling Hudson but this would have just made them look desperate in the face of the rise Jacinda Ardern has given them in the polls.

Dunne no doubt looked even further into the political crystal ball and realised that if he did make it back Winston Peters would most likely be National's partner - and he would be shut out of Government.  No wonder Dunne quit - even on the best case scenario, there was nothing to look forward too.

The dirty deal with Dunne was pretty pointless given the chances of National getting together a Government with him and Act and the Māori Party have pretty much disappeared.

Depending on how the MMP mathematics worked, if Dunne stayed - and won - he could maybe give National an extra seat on paper. But thanks to the rise of Winston and fall of National it won't be needed - so what's the point?

The problem for National is due to all its "vote for Dunne" mixed messaging it may now be way too late to save the seat.

The base political fact is this: Dunne quitting serves only as a symbol of Ardern's rise.

Patrick Gower is Newshub's political editor.