It's not easy in the centre
It is early days to judge what impact the change to MMP will have on the eventual shape of New Zealand politics, but after six elections the signs are that MMP has bred three relatively stable parties - National, Labour and the Greens.
Four more parties are in Parliament and the Conservatives secured a debut 2.7 per cent of the party vote in the last election, but none can claim to be securely placed.
The Maori Party (or maybe Mana) may establish a long-term position by continuing to win electorate seats but clearly has acute succession problems. Both New Zealand First and UnitedFuture appear entirely dependent on their leaders' longevity.
The attempt to establish a party of the sane libertarian-right seems to have failed and indeed ACT only secured representation when it was pursuing populist law-and-order and race-relations policies and chasing scandals.
The Conservative Party made an impressive debut in 2011 but leader Colin Craig spent more than Labour to do that and it is too soon to assess whether it can establish a secure place in New Zealand politics.
There are advantages and disadvantages for the two main parties in this configuration.
For a start, National by default vacuums up almost all of the "right" votes whereas Labour has to compete on the left. That means that unless or until another party emerges to the right of National they will mostly be the largest party.
This is potentially a big problem for Labour.
Every Government under MMP has been led by the largest party. The swing parties have sometimes said they will negotiate with the largest party first.
In 2011 there was a big disconnect between the overwhelming expectation National would win and the closeness of the centre-left and centre-right voting blocs. It would have been a big shock if a slight shift in votes left the Maori Party as kingmakers.
That disconnect still exists. The centre-left and centre-right blocs have been deadlocked in most polls but a majority in a March UMR survey expected a National-led coalition to win the next election (51 per cent National, 28 per cent Labour; 21 per cent unsure)*.
To win in 2014 Labour will almost certainly have to communicate the legitimacy of winning from possibly as much as 8-10 per cent behind the National party vote.
As is often pointed out, the downside for National is that it has no obvious or even seemingly compatible coalition partners.
John Key played the integrity card by ruling out New Zealand First as a coalition partner in 2008, but now he faces the unpleasant choices of courting New Zealand First and/or undertaking high-risk and possibly futile electorate plays in Epsom or Rodney - or a combination of all three.
National voters do not seem to want a bar of the two likeliest options.
Only 6 per cent in a UMR February survey rated NZ First as a good coalition partner and 63 per cent as bad. Only 5 per cent rated the Conservatives as a good coalition partner and 52 per cent as bad.
The Greens (10 per cent good, 56 per cent bad) rated a little higher amongst National voters.
Labour has ended up placed in the centre of the stable three-party grouping. It will probably, for the foreseeable future, only win Government with the Greens locked on as a serious 10 per cent-plus coalition partner.
Some may see the centre as the place to be. It's certainly where the voters say they are.
Asked in a UMR April survey to place themselves on a 0-10 scale running from 0 (very left) to 10 (very right) 40 per cent were in the 4-6 span and a further 22 per cent can be added if the centre is stretched to the 3-7 points range.
But it does not mean Labour dominates the centre vote either. Of the 40 per cent who placed themselves in the centre of the New Zealand political spectrum in UMR's April poll, National has 48 per cent support and Labour 31 per cent.
National is already trialling a Greens-pulling-Labour-to-the-mad-left attack lines for 2014.
Celebrated political scientist Maurice Duverger famously declared "there is no centre in politics".
He argued that the centre was only an artificial grouping where the moderates of the right and left met.
Every centre was "divided against itself" and its fate "is to be torn asunder, buffeted and annihilated - torn asunder when one of its halves votes right and the other left, buffeted when it votes as a group first right then left, annihilated when it abstains from voting".
Proportional voting systems tend to mute this terrible fate but the dangers of being in the centre still exist.
In 1995 a group of seven seemingly credible centrist MPs from Labour and National formed the United Party with the objective of being always in Government as a moderating influence on either a Labour or National-led government.
This "sensible" party bombed in the 1996 election with only Peter Dunne surviving in his Ohariu electorate stronghold.
The somewhat less-sensible New Zealand First became the kingmaker.
The Greens can almost always outflank Labour on the left leaving it to sell qualified reasonable middle-ground policies that do not necessarily inspire supporters.
Being in the middle also does not always play well in a media world demanding crisp soundbites.
When Labour and the Greens jointly released a policy on electricity pricing that was praised as bold and radical and criticised as loony and North Korean, the Greens were still able to position themselves as going one step further with their add-on of progressive pricing.
When the SkyCity-Government deal was announced the Greens pledged to tear it up, Labour deferred to the fine print.
Labour has also long been bedevilled by the left slot in standard right v left setups, often going to commentators who, while opposed to National, are at best somewhat conflicted regarding Labour.
The New Labour Party which split from Labour in the 1980s to establish a shortlived true-believers party on the left has spawned an extraordinary number of media commentators led by the redoubtable Chris Trotter.
It may actually be better for Labour - and perhaps too for National - for a stable party to emerge clearly to the right of National.
For Labour that would automatically make it a closer fight to be the largest party. Ideally for Labour that party would adopt policy positions which would clarify the right as a greater threat to left and centre voters than National is.
And National would get a stable and acceptable coalition partner. But that is not going to happen anytime soon.
* All quoted poll results are from questions included in UMR's two-weekly monthly telephone omnibus survey. This is a telephone survey of a nationally representative 750 New Zealanders aged 18 years-plus.