Last week, at the New Zealand Economic Forum at Waikato University I was part of a panel discussing whether MMP had contributed to social cohesion.

I argued that MMP had definitely made more Parliament more diverse and representative of contemporary New Zealand by giving the opportunity of a wider range of political opinions to be expressed. However, it was doubtful that it had contributed positively to social cohesion. Indeed, I suggested that, contrary to expectations, MMP has actually had a negative effect on social cohesion.

When MMP was introduced it was generally and correctly assumed that the old National-Labour duopoly that had dominated New Zealand politics since the 1930s would be challenged by emerging new parties representing important shades of opinion not always given appropriate consideration within the two old parties. It was also expected that this would enable National and Labour to focus more specifically on their traditional audiences, rather than the broad churches they had become over time.

At the same time, it was thought that as the two main parties redefined themselves, the moderate centre ground of politics, previously found in elements of both National and Labour, would assert itself independently and strongly, and play a pivotal role in the composition of future governments. Where new parties emerged, representing specific issues, philosophies, or ethnicities, they were thought likely to be either to the left or the right of the major parties.

In fact, things have not quite worked out that way. National and Labour have repositioned themselves aggressively as competing parties of the centre ground. In the process, they have not only killed off the moderate centre as an independent political voice, but also empowered more strongly the more extreme parties on the right and left on whom they must now rely to form a government when the opportunity arises.

So, rather than have a situation where the centre ground of politics moderates the performance of the two major parties when in government, the reality now is that National and Labour have become hostages to their more doctrinaire support partners. Rather than be moderated by the centre, National and Labour often have to be the handbrake on the small parties supporting them in government.

One of the reasons why the National Party today often looks indecisive and ineffectual within the current coalition government is because much of the focus of what it does is trying to keep the competing demands of ACT and New Zealand First in check, rather than implementing its own policy agenda.

And that means that both ACT and New Zealand First have an influence in government disproportionate to the vote share each received at the last election. It will be no different if Labour leads the next government and is similarly beholden to the Green Party and Te Pati Maori.

This is not to say that the views represented by ACT, New Zealand First, the Green Party and Te Pati Maori have no place at a government’s table, nor that each has no right to demand the implementation of some of their key policies as the price of supporting a government. Rather, the point is about relative proportion.

By shutting out any role for a sensible moderator, National and Labour have both, perhaps inadvertently, empowered the more extreme voices in New Zealand politics to a level not imagined at the time MMP was introduced thirty years ago. And that is where the impact on social cohesion becomes relevant.

There is no doubt that New Zealand today is a more divided society than it was before. In part that arises because we have become a more pluralistic society since the 1990s. And it follows that there are political parties now in Parliament that reflect aspects of that new pluralism.

But this is where the question of relative proportion becomes important and starts to impact on social cohesion. The way in which our MMP system has developed has delivered disproportionate influence to some political groupings. In turn, that disproportion has disrupted social cohesion by rewarding some with more political power and influence than their voter support merits, often at the expense of others who are left feeling they are missing out. National, Labour and the moderate centre where most voters reside, have often been left playing second fiddle to parties whose actual support amongst the electorate is low.

When MMP was developed in Germany after World War II it was seen as the best system to prevent the emergence of extreme voices in politics as had been the case in the 1920s and 1930s. It was hailed throughout the 1950s and 1960s in playing a major part in West Germany’s Wirtschaftswunder or Economic Miracle. So it was little surprise that when a Royal Commission considering the best proportional representation system for New Zealand recommended in 1986 that we introduce MMP.

Sadly, the way it has developed here has enhanced neither economic prosperity nor social cohesion.