The Greens are running a fundamentally dishonest campaign line. Last week co-leader Russel Norman suggested the only way to get rid of National was to vote Labour or Greens.
Yet this is entirely at odds with his party's new coalition policy that says that - for the first time - the Greens would consider giving their support to putting National into government.
The tag-on, of course, is that such a situation is "highly unlikely". This position is entirely slippery.
By deliberately not making up their mind until after election day, the Green politicians take away the ability of voters to know what sort of government they are voting for when they vote Green.
Before elections, voters (and political journalists) are right to demand clarity from political parties about with whom they would be willing to form governments.
Minor parties have done a huge disservice to MMP by being deliberately opaque about post-election coalition arrangements. Winston Peters has been the worst offender. In 1996 he campaigned on getting rid of the National Government but then joined National in a coalition. Similarly, in 2008 the Maori Party was vague about coalition possibilities but gave the strong impression it would not work with National. It then did exactly that.
The Greens and National could work well together. Those who doubt this are under the mistaken assumption that the Greens are still a radical left-wing party.
But they have undergone a significant political shift and reorientation recently.
Under the leadership of Russel Norman and Metiria Turei the Greens have been on a mission to reinvent themselves as a more moderate, centrist and pragmatic party.
Sick of being denied power, the party has ditched its emphasis on more radical policies, marginalised its previous leftwing MPs and activists, and adopted a much more professionalised approach.
The party is now business-friendly and seeking to win over swing voters by what it calls "moving into the suburbs".
You no longer hear talk of reducing GST back to 12.5 per cent or reversing tax cuts.
The Greens are playing a dangerous game. By wanting to get into government so badly, the party risks its reputation for being principled and almost beyond politics.
The price for Green ministerial positions and other sweeteners would be swallowing an awful lot of "dead rats". And every minor party that has gone into government has been punished by its voters at the next poll.
If the Greens were in a genuine kingmaker position after the election, they'd be more likely to give their support to Labour. But in the more likely scenario of Labour not being able to form a government, would the Greens then throw their lot in with National to get ministerial portfolios? It's highly likely.
After all, National is in desperate need of coalition partners, as the future of its current allies looks very dim.
It needs to foster a potential ally it can work with beyond this year, and the Greens might be shaping up to be that option.
But it might not be with the support of its traditional voters.
No left-wing voter or opponent of the current government can justifiably vote for the Greens while the party refuses to say whether or not it would support a National government.
Dr Bryce Edwards is a lecturer in politics at the University of Otago. He writes a blog at liberation.org.nz