Supplementary is mixed-member-disproportional
There are two mixed-member systems on offer.
Mixed-member proportional and mixed member majoritarian, also known as both supplementary member and parallel voting. At a glance, one system appears to be fully proportional, and the other semi proportional. It is being promoted by big business as a sensible compromise between first-past-the-post and mixed member proportional.
But one glance at the outcomes of supplementary member elections gives lie to that description. Rather than being slightly more proportional than first-past-the-post, it is more disproportional than that legendarily disproportionate system. If Aotearoa was voting with the supplementary member system on Saturday week, the Green Party could be expected to win only four seats, rather than the 16 that current polling suggests is possible.
The reason supplementary member produces such a skewed result is not entirely intuitive. It is a salutary lesson in why the arcane art of designing fair electoral systems shouldn’t be something that the general population should ever have to concern itself with. It is the reason that determining significant changes to a nation’s democracy should be subjected to a full-blown commission of inquiry, and only then should there be a referendum, and a binding one—but that is another issue.
The Royal Commission on the Electoral System carefully considered supplementary member for Aotearoa, and found it wanting:
SM is not a proportional electoral system, and therefore does not attempt to overcome the problems inherent in plurality in single-member constituencies. The fact that only the additional seats are allocated proportionally and without regard to the results of the constituency elections means that the total seats won by a party are likely to remain out of proportion to its share of the votes.
At the time it was studying the available options, supplementary member had yet to be implemented by any country, and the royal commission was initially loath to rule it out. Presumably, had the commissioners had the benefit of seeing how badly it skews election results in Japan, they would have wasted no time in disposing of it as superficially appealing but inherently undemocratic.
The supplementary member system proposed in Saturday’s referendum would have 30 seats allocated according to the party vote, rather than 60 in the current system. New Zealanders could readily suppose that this put supplementary member halfway between mixed member proportional and first-past-the-post. However the 30 and 60 figures are deceptive. With mixed member proportional, all 120 seats are allocated proportionally—the 60 list seats correct the proportion each party receives, provided of course that the party reaches the threshold. The net result, at least in the last two Japanese elections where 37.5% of the seats are allocated proportionally, three gross distortions occur:
- The winning party receives a disproportionately high number of seats
- The runner-up receives a disproportionately low number of seats
- The third party is all but extinguished.
The superficial appeal of supplementary member means that a number of countries have proceeded to try it, seeing it as a low risk means of introducing a modicum of proportionally. Some, including Kazakhstan, have since reverted to first-past-the-post, finding that the supplementary seats were seen as a rort.
Of the 17 countries using mixed member proportional, the only Japan is classed as a full democracy. But aside from its patently disproportional electoral outcomes, New Zealanders should be wary of using Japan as a democratic role model, given that the sovereignty of its people is illusionary:
Since the end of the American occupation, Japan has been regarded by the West as a democracy, but in reality it works very differently from any Western democracy: indeed, its modus operandi is so different that it is doubtful whether the term is very meaningful.
The particular rort that is rewarded under the supplementary member is the ancient art of the gerrymander. In a robust proportional system, the government of the day can preside over any amount of gerrymandering, but it will have no effect on the overall election result—Epsom-style Machiavellianism excepted.
On Saturday, New Zealanders should vote to retain mixed member proportional and hasten its overdue tune-up.
Ordered by urgency of deployment
- Year-7–15 voting as curtain-raiser
- Universal year-7–15 voting in schools—extended Kids Voting
- Election Day enrol-and-vote
- Concurrent elections, which will quickly recoup the costs of 1–3, and pay for 4–11
- Lifetime licence to vote
- Pre-enfranchisement voting
- Pre-enfranchisement enrolment
- Lowering the age of enfranchisement—currently some turn 21 before being allowed to vote
- Fixed, holidayised, Mondayised, and festivalised Election Day
- Online voting
- Anytime voting*
*If not strictly evidence-based, then at least, strongly evidence-suggested.