If National maintain current polling and both the Conservatives and New Zealand First get to five percent, Key will be in the catbird seat. But which might he choose and why?

With two weeks to go until election day, it looks highly likely that John Key will be Prime Minister until 2017. The idea that Labour on around 25% could lead a government is improbable. And it's now hard to imagine anything that Kim Dotcom could disclose that will change the voters' minds. The voters are making their decisions on the basis of their experience of living with a National government over the last six years, not on anything that Dotcom may say on the 15^h.

There are of course those on the Left who say there are hundreds of thousands of voters who only have cell phones and who are itching to get to the polls and vote out the most evil and corrupt government in New Zealand history. I guess we will know on Saturday the 20^th.

But if this does not come to pass and it is John Key returned, then it is time to speculate on coalition partners, especially if the Nats don’t quite get to 50%. That means the Conservatives and New Zealand First are both options as coalition partners (the minnows of ACT and UF already being taken into account).

What if they both get more than 5% of the party vote? After all, if only Winston gets there this discussion is rather moot.

In the case of both the Conservatives and NZ First getting 5%, John Key is faced with a tricky choice. It will turn on both policy and personality.

Taking personality first. With Winston, there is history, and there is bad blood. The coalition of 1996 to 1998 did not work out well, but that is nearly 20 years ago. There is also 2008 and the Owen Glenn donation (disclaimer here, I was on the Privileges Committee at the time). That directly led to Winston going out of parliament for three years. But since 2011 we have seen a more temperate Winston in the House. He is aware of the need for a legacy, and the Nats know that.

In contrast we have the somewhat hubristic Colin Craig. One of the reasons the Nats would not deal with him over East Coast Bays was his completely unreasonable demand that the Nats remove Murray McCully from the ballot paper. Imagine what Colin might be like if he gets 5%. It is all too likely to result in a rush of blood of blood to the head.

So no easy deal there.

On policy there is an interesting contrast. In many respects the Conservatives, at least in respect of economic policy, sound like ACT with some populism thrown in. Coupled with Colins' conservative social policy, the Nats will worry that giving away very much to the Conservatives would simply blow up the Nats. And make a fourth term an absolute impossibility.

In contrast Winston tends to be a bit of poodle on policy, his pre-election statements notwithstanding. And the reason is because at heart he is a traditional Nat.

The things that Winston really wants are able to be accommodated by a pragmatic Prime Minister, who might in any event be tempted to claim the credit for them as they are implemented. They will, after all, be quite popular initiatives, and could soften National’s somewhat flinty image. That sets up a fourth term quite nicely.

So much of this turns on legacy issues. Does Winston want to go down as someone who made an enduring difference to New Zealand and whose party has continuity beyond his leadership? Does this imply that Shane Jones could come back into Parliament in 2017 as the putative next leader of New Zealand First? In many ways Shane is naturally aligned to the political ethos of NZF.

I suspect that much will depend on the style of the entreaties, both public and private, that Colin and Winston make in the first few days after the election.

Key would be in the catbird seat. But the question of the prospects of a fourth term will weigh heavily on him. And it may be that, rather than any immediate political calculation, that will determine John Key’s choice.