What was behind the Green Party approach to Labour to campaign jointly as an alternative government in the lead-up to the election on 20 September?
The Greens have not yet held their annual conference, nor gone through the process of canvassing their members about which parties they could do deals with after the election. So to be proposing a quite formal relationship already with Labour seems premature, even if it is logical.
It is the logic which the Greens say prompted them to make the approach.
It is also likely, though, that the Green Party wanted to get a genuine commitment from Labour to an alliance which has previously been evident in the two parties' announcement of a joint New Zealand Power policy and the work they did with New Zealand First and Mana on the manufacturing inquiry.
But Labour has always had a fraught relationship with the Greens. While the two parties have much in common - probably more in common than any other two parties in Parliament - they are also keen competitors for some of the same vote.
Their past history is also not positive, with Labour having frozen the Greens out of government on more than one occasion.
Does the Green Party want to tie Labour to a coalition deal now to avoid another disappointment after the election?
The Greens need not worry. The polls have consistently shown that Labour will not be able to form a government, if it is in a position to do so, without help from the Greens and probably New Zealand First.
A competitor and ally
Protecting Labour's vote appears to have dictated leader David Cunliffe's decision to reject the Greens' offer.
Labour, still sitting in the low 30s in the polls, is determined to lift its vote as high as possible. In part - as the Greens co-leader Russel Norman recognises - it sees the Green Party as much, if not more, a competitor as it does a likely ally in government.
That has been accentuated by the National Party's effective scare campaign about a possible Labour-led Government being pulled to the extreme Left by the Greens.
Labour MPs report National's scaremongering is working among centrist voters, particularly in provincial New Zealand. Those voters worry a Labour-Green Government, as portrayed by National, would put a brake on economic growth, putting pressure on their jobs and incomes.
In the past two elections those voters have supported National. For there to be a change of government Labour needs to persuade at least some of them to change their vote. It does not believe that likely to happen if centrist voters believe they are voting for a Labour-Green Government.
The Greens dismiss that analysis and say National has been given great power by letting it dictate Labour's political strategy. They argue that National's scaremongering has no merit and Labour should be prepared to counter it rather than run scared.
The consequences of Labour spurning the Greens will play out differently across the country. In provincial electorates it might re-assure wavering voters considering ticking the Labour box. But in urban liberal electorates like Wellington Central it might cause some consternation among people who consider Labour and the Greens as interchangeable.
Labour could possibly lose some votes to the Greens from urban liberals but pick up support from more conservative voters in provincial New Zealand.
But no matter what, Labour says now one thing is clear: If National is unable to form a third-term government later this year it is almost inevitable that Labour and the Greens will be at the core of what replaces it.