Honestly, I struggle to fathom it myself. National had a high vote in the Key years because Key was teflon. People loved him, for whatever reason; even my father, originally a Key voter, disavowed him in the end.
This is Labour/Green's election to lose. And I think that's part of why the Nats have a high vote: the Kiwi left is split between Labour and the Greens. But with MMP that should be of little consequence. The Greens can't win any local seats, so Green voters - like me - will vote Labour for their local seat and Green for list. In 2014 there was no realistic prospect of anybody but Key winning, and Labour lacked a popular leader, so of course the Nats have almost a majority despite MMP.
Now? Jacinda Ardern is popular, and Kelvin Davis brings the Māori vote. Our largest opposition party is led by a woman and a Māori man. That's got to mean something. The Greens will run well - Metiria Turei's admission that she lied to WINZ (the equivalent of Centrelink) can only help her with marginalised or disillusioned voters. The people angry with her would never have voted for her anyway. And nobody likes Bill English. The last time he led the Nats, they got flogged.
I'm still worried, because the left are working at a serious electoral disadvantage. But with the help of the Māori Party or - shudder - NZ First, I hope a Labour/Green government will get over the line rather than some Nat scumlords.
I'm so close to going home and joining the fight, you have no idea. Fuck Australian politics, I don't care about anywhere but Melbourne. I'll fight for New Zealand though.