Obviously Jacinda Ardern has been not just a circuit breaker, but a game-changer for Labour. Her ascension has hit the Greens at the same time that Meteria Turei's leadership was being called into question, and appears to have been a double blow that has caused the Green Party to shed support. At the same time, on the surface of it, it looks like New Zealand First has lost support to Labour too, with National only down 0.8 points in the Newshub poll.
At first glance I, along with many others, assumed that it was Jacinda Ardern taking votes off the Greens and New Zealand First. But the more I've thought about it, I'm not entirely sure that's the case. I can see why Jacinda would reclaim support from the Greens where she'd get back some of the former Labour supporters that Andrew Little had lost to them, but I'm still not quite sure why as much of New Zealand First's support would go her way as initially appears to be the case.
What I've since released is that there's another possibility, that it might be more likely that there's been a significant number of undecided voters in these polls who have come off the fence in support of Jacinda. My understanding is that these polls usually just report on decided voters, leaving undecideds out of the final numbers presented (though I'm not 100 per cent sure this is the case). What might be motivating the movement of these undecideds is that they perceive Jacinda as having the ability to not just to be a very capable leader, but also to transform Labour into a party they can support. They identify with her values, her identity, and her brand, in a way that they just couldn't with Andrew Little.
I've arrived at this conclusion mainly because I can see there being two logical places for Jacinda to get already committed voters from - the Greens and National. The Green voters she'd get back are the disenfranchised Labour supporters who didn't rate Andrew Little, the National voters she'd win are those in the centre ground who turned out to vote for Helen Clark in 1999, 2002, and to a lesser extent in 2005, and who I think Jacinda has a very strong appeal to.
Given that National and Bill English's support hasn't budged much in either of the polls I linked to in the first paragraph, I think New Zealand First might be leaking its support to National. What I think is happening here is that conservatives who have gravitated to Winston Peters over the past year and returning "home" to National in the face of Labour's recovery. Jacinda, meanwhile is broadening Labour's support both at the expense of the Greens and National's centre-block, and bringing in those undecideds I already mentioned, so National's loss of support to Labour is masked to some extent by gaining back voters from New Zealand First.
At this stage it's all instinctual guesswork on my part, but I've asked Newshub's Political Editor Patrick Gower if he can shed any light on the matter, as Newshub's polling data bank doesn't reveal what the undecideds were in each poll. We'll wait to see if more details come out in the coming days.