Writing in the Herald this morning, Philip Temple argues that it is time to fine-tune MMP. He first argues that it is too easy for small parties to gain representation, and that therefore the one electorate rule (which allows parties to dodge the threshold if they win a single electorate seat) should be removed or increased to two electorates. But this has things exactly backwards. The problem with the threshold is not that it is too low, but that it is too high.
The very basis of MMP (and any other proportional representation system) is representation; parties should be represented according to their level of support in the community. An arbitrary cutoff is prima facie incompatible with this, and needs strong justification. And sorry, but in NZ "keeping the extremists out" just doesn't cut it; we just don't have enough of them for that to even be credible. And even if we did, the answer is to defeat their arguments, not deny them representation. That is difficult to do with a party that uses organised political violence, as the Nazis did - but then the thing to target is political violence, not abuse democracy by denying people their say.
While I loathe Christian Heritage and Destiny as much as the next person, if I deserve representation in Parliament, then so do all the people I disagree with. It is as simple as that, and we should be bending over backwards to ensure that people are represented - not denying them arbitrarily by a mechanism that smacks of a big-party jackup.
(And because someone is bound to mention it: go and look at the Nazi party's election results and then try telling me with a straight face that a 5% threshold would have kept out of power a party that repeatedly got more than 30% of the vote...)
By keeping smaller parties out of Parliament, the threshold is also a barrier to the marketplace of ideas. New parties cannot get established, while older ones' fortunes are artificially boosted by the threshold's self-fulfilling prophecy. This is not good for democracy in the long run. If we want our democracy to remain healthy, if we want our political meme pool to maintain the sort of diversity that allows voters to make real choices, then the threshold needs to be lowered, not raised.
Finally, Temple's reason for raising the barriers to small parties is that this would allow our Parliament to shift towards the "real MMP model" of two main parties supported by "two or three" smaller ones, rather than our untidy clutter of majors, minors, and minnows. To which the response is that the structure of our Parliament should be decided by the voters, not by political scientists. Rather than trying to change the political system to ensure someone's idealisation of the perfect arrangement of parties in Parliament, we should instead establish a level playing field between parties and let their fortunes rise and fall in accordance with the wishes of the electorate. And the way to do that is by lowering the threshold, not by raising it.
(If you're looking for arguments about the Maori seats, see here)