History suggests that National will overcome the ' third-term blues' to win another general election. Since 1998, the party leading the opinion polls in July of the year preceding the election has gone on to win the highest proportion of the party vote come election day. I' m prepared to make a similar prediction for the 2017.
With the late June to August 2016 public opinion polls all showing National leading Labour by a margin ranging from 12 to 18 percentage points, National looks to be in pole position to form the next government.
To make sense of this we need to understand early deciding voters; those who reach their voting decision before the election campaign. In New Zealand they represent an average of 54 per cent of voters, 75 per cent of whom end up voting for a major party.
Importantly, early deciding voters have voted for the party that has won the highest proportion of the party vote in each of the last seven elections.
The two times that the government has changed in the MMP era (1999 and 2008) is after early deciding voters switched their vote decision from the major party challenger to the election winner the year before election year.
This makes these voters a good barometer of the election outcome. (The chart below illustrates this with figures from the New Zealand Election Study).
Early deciding voters tend to base their decisions on a longstanding predisposition towards a particular party, as well as performance measures they know or can estimate long before the actual date of the next election. Over the past three election campaigns an astonishingly high 73.8 per cent of National voters have reported reaching their voting decision before the start of the election campaign.
These voters know the National-led government, their policies, their ways of working and John Key' s leadership. National has a track record of stability and, incredibly for a third-term major party, has shown very few cracks in caucus unity.
If the past state of the economy has been positive - particularly if it has got better - early deciding voters use this to predict future trends. Economic indicators are still largely positive, aside from rampant house price inflation and lack of supply in Auckland. With a voter base that is predominantly comprised of homeowners whose asset values have risen, however, National voters will not be wanting or predicting the economy to tank between now and election day 2017.
Labour-leaning early deciders face a lot more unknowns, ranging from Labour' s new vision and policies to whether Andrew Little has what it takes to be the next Prime Minister. It takes time to build credibility as a political party leader.
Jim Bolger and Helen Clark were leaders of the Opposition for 4.5 and six years respectively before becoming Prime Minister.
John Key was leader of the National Party for just under two years before he became Prime Minister, but the opinion polls had already switched in National' s favour when he took on his leadership role.
Also working against Labour' s ability to secure the early vote is the 31 May Labour/Greens agreement to builda basis (my emphasis) "of a stable, credible and progressive alternative Government".
It is a commitment to being more cooperative in the lead up to the election, but it' s not an offer of a coalition government and voters have to wait to see what it really means.
Labour might be thinking it has a bit of time up its sleeve. After all, only two-thirds of Labour' s supporters reach their vote decision this far out from the campaign; the other third wait until the campaign to reach their decision. But Labour will have to work hard for the late deciding vote.
To be in a position to replace National, both Labour and the Greens need to attract late deciding voters away from National and New Zealand First.
On average 41 per cent of voters who reach their decision during the campaign give their vote to a minor party. The next highest cohort (31.9 per cent) give their vote to the major party that ends up winning the highest proportion of the party vote. Labour hasn't won the majority of the late deciding vote since 2005.
It is also by no means guaranteed that joining forces with the Greens will see their combined vote rise. Late-deciding Labour and Greens voters tend to "eat each other' s lunches".
In other words, when Labour' s late-deciding support rises, the Greens' support falls and vice versa. To be in a position to replace National, both Labour and the Greens need to attract late deciding voters away from National and New Zealand First.
This will happen, but not until Labour is in position to switch places with National in the year beforethe election. Because this did not take place in 2016, history suggests we are at least two years away from Labour trading places with National in the opinion polls and four years before Andrew Little becomes Prime Minister.