Some 62.7 per cent of National voters make their voting decisions before the election campaign; 40.4 per cent of them make that decision before election year. It is these voters Labour needs to reach across to if it is to have any chance of regaining the box seat - but most of them have already made up their mind, and it will take a miracle to convert them.
David Cunliffe will need to convince National voters that his recent rekindling of Labour's relationship with the union movement is also in their interests. It may have worked to shore up Cunliffe's leadership ambitions, but persuading more conservative centre-right voters to swing to the left will not be such an easy ask.
Without being able to rely on these voters, Cunliffe will have to share the spotlight with the Greens' Russel Norman and Metiria Turei in order to present a viable leadership alternative to the National-led government. This isn't necessarily an easy coalition. The closer they get to Labour, the Greens risk becoming regarded as 'Labour-lite'. If they are to grow their support base they need to keep taking voters off Labour and presenting themselves as significantly different from Labour.
Conversely for Labour to grow they need to take votes off the Greens, which means that they can't become too chummy either. It won't be easy for either party to present itself as a shared and unified offering when deep down they are competing for the same votes.
Although David Cunliffe emerged from the Labour leadership 'primary' with all guns blazing, recent political history also suggests he will find it hard to make a sustained impact within the next 12 months. The MMP era is littered with major party leaders who have rolled their predecessors with the hope of doing better within two to three years of the next election, only to fall by the way.
John Key was the exception as leader of the Opposition for just under two years before he became Prime Minister; before that Helen Clark was leader of the Opposition for six years, and before that Jim Bolger was leader of the Opposition for 4.5 years. No one has yet gone on to lead a government within 12 months of assuming party leadership.
Of course none of this means that forming the next government will be easy for National. Its current support parties in government - ACT, United Future and the M?ori Party - have all suffered serious reputational damage and declining popularity over this term of government, and their continued ability to survive the next election, let alone collectively prop up a National-led coalition, is not guaranteed.
Of the three minor coalition partners, the M?ori Party is the most likely to survive through the 2014 election. David Cunliffe has too much on his plate over the next 12 months to be able to reassure voters in all the M?ori seats that he is in a position to prioritise their interests. So there will still be room on the political spectrum for a party or parties dedicated to M?ori needs. With a new leader in Te Ururoa Flavell, we are likely to see a reinvigorated M?ori Party, but it's not looking likely that M?ori and Mana parties will be able to reconcile over the next 12 months in order to win all the M?ori seats.
As always in New Zealand politics, the wildcard is New Zealand First. Assuming that Winston Peters wants to take another crack at electoral politics (and there are no signs that he would not) it should be expected that New Zealand First will wait until the election results are known before committing to any arrangement. Assuming that the party gets over the 5 per cent threshold, its main options would then be to go into coalition with National, go into coalition with Labour and the Greens, or remain on the cross benches and vote issue by issue.
With a party membership that has previously indicated a preference not to be in formal coalition with National, and faced with the alternative prospect of being the third (and least important) party in a Labour/Greens coalition, the most likely scenario is that New Zealand First will choose to stay on the cross-benches, supporting a minority National Government on confidence and supply, much as it did for the 2005-2008 Labour-led government.
In this scenario it would be in the powerful position of having the casting vote on every piece of legislation before the House, with management of a Cabinet portfolio or two thrown in for good measure.
But there is an even wilder card that may yet disrupt this scenario: the Conservative Party. In the 2011 election it got 2.65 per cent of the party vote, which is more than any of National's coalition partners.
Off the back of population increases it is possible that a new electorate may be formed north of Auckland, currently a National-leaning geopolitical zone. It would not be without precedent for National to 'gift' the winning of that electorate to party leader Colin Craig to ensure that the Conservatives' party vote may be counted in a new centre-right coalition bloc. National might then be able to govern without the need for the support of New Zealand First. Either way, it has options.
Professor Claire Robinson is a political commentator and Pro Vice-Chancellor of Massey University's College of Creative Arts.