The polls are closing, making even the smallest parties significant players over the next two weeks

This week's poll of poll results shows the gap closing between the parties of the right and those of the left (with or without New Zealand First). The big movers are the Greens, up 0.7 percent, with National the big losers, slipping by almost a full percentage point. Still, pull the coalitions together and a National-led government remains on the cards. With Act and now United Future declared National party supporters, that trio can pull together 63 seats on current polling. Even with an overhand of 124 or 125 (that is, an extra few MPs created by the fact that the Maori Party and Progressives get more electorate seats than is warranted by their proportional party vote), they can still squeak a majority.

The fly in that ointment is that the momentum is against them, and if you've been following the US elections for the past two years you'll know the value of momentum. Barack Obama is momentum's master; all you have to do is be ahead on election day, the polls a week before or a week after mean nothing. Timing is everything.

As our friends at 08 Wire point out, it looks a bit harder for the centre-right coalition if you average merely the four polls that came out over the weekend, ignoring the polls before that.

The average of those four polls has National on just over 46%, 11% ahead of Labour. In terms of the coalitions, NUFACT has an average of 49% support, whereas Team LPG has 44.1%, and Team LPGM has 46.6%. On these numbers, NUFACT would probably become the government with a majority of one. But the recent trend has been of a narrowing trend – the three polls from early October estimated NUFACT at nearly 51%. If this simple trend keeps up for two more weeks, then Team LPGM would have the numbers to govern, and probably to govern with a popular mandate.

Given all that, lord knows what campaign the Herald leader writers are watching. By all-but calling it for National on Friday in a fit of over-eagerness, they undermined the independence they've long claimed as a non-partisan paper.

The fact is that as the race gets tighter, the number of variables get greater, because even the smallest parties could top the balance with just a couple of MPs. The Maori Party remains the most likely king-maker, with New Zealand First having the potential to give a huge boost to the left if it can get off 3 percent support. But talking to a United Future staffer last week, before Peter Dunne announced for National, he was talking up the potential of his party holding the balance of power. He imagined a scenario where National got 57 seats and Act three, while, say, Labour got 45, the Greens nine, the Progressives one and the Maori Party six. That's 60 v 61. United Future polls 1.26 percent and gets two seats, making them the decider.

It's that kind of eventuality that John Key has hedged against with this weekend's deal. All Key had to sacrifice was his policy to merge the Families' Commission with the Children's Commission. (That's a few public servants spared National's "razor"). Still, as David Lewis has argued today, you never can tell with Peter Dunne. It would be a huge political punt, but once he's won Ohariu-Belmont he could always find a post-election reason to change his mind.

Both parties want an MMP referendum; are keen to get some competition into ACC; want a fair amount of reform to NCEA; want some form of victims' reparation scheme; support private-public partnerships in roading, health and prisons; and to re-jig the Emissions Trading Scheme. The main potential clash is over KiwiSaver. Dunne's a fan of the existing scheme.

So the Key-Dunne deal gives National a smidgen more breathing space. It's a sign that National can see the finishing post looming and the gap narrowing at the same time, and is getting nervous. Really, a couple of seats either way is going to swing this.