Why Don Brash supports the Supplementary Member electoral system

New Act leader Don Brash today announced his support of the Supplementary Member (SM) electoral system - and no one should be surprised. It's the only electoral system that gets him what he wants.

Although he doesn’t like MMP much, he doesn’t want to go back to First Past the Post either. Entry to Parliament via the list is effortless if you have party backing for a high list place, as Brash did under National. He thinks Supplementary Member should be able to let smaller parties be represented in Parliament, and likes the fact that the list has let people like himself into parliament, but prefers that there are fewer list place. He welcomes under SM, that there will be fewer places, and that minor parties on the Left would get disproportionately fewer of them.

That is because under SM, only the list seats are proportional, and the electoral system guarantees a huge majority for a party that wins both a lot of electorates and a large share of the party vote. MMP is a proportional representation system.

Brash does not support proportional representation, or the recommendation of the Royal Commission on the Electoral System in 1986, that rejected supplementary member. While he wants to see limited and disproportionate power of minor parties in Parliament, he is aware that, under current polling, changing to SM won’t make too much difference to Act if it wins Epsom.

Not so the Greens. If Act were to win Epsom under SM, it would have about the same number of list MPs under SM and MMP, whereas if the the Greens were to get 10 percent, they'd have a proportionately bigger reduction of MP numbers under SM compared to MMP.

Brash also noted that it was not fair that in 1981, Social Credit got 21 per cent of the vote but only two seats. It is also not fair that Social Credit would have got proportionally fewer list seats than other parties under Supplementary Member. Of course, the electoral system is a factor on how people vote, so the 1981 vote may have been slightly different under a MMP or SM electoral system.

Actually, in both 1978 and 1981, the winning party, National, got more than half of the seats with less than half the vote and that was the catalyst behind the electoral system change to MMP.

Here's an illustration from The Standard blog that compares the MMP vote to what the SM vote would have been in both 1999 and 2008.
As you can see, the number of Alliance MP's would have halved under SM in 1999, and the Greens,while having a higher share of the vote in 2008, would have the same number of seats after both elections.

According to the Greens, had the 1996 election been held under Supplementary Member with 100 seats, the 35 list seats would have also been unevenly distributed, National and Labour would have had about the same number of seats they would have in a 120 member parliament, to the detriment of the smaller parties, who overall would have had proportionally fewer. NZ First elevated its share of the vote due to its hold on the Maori seats.

Don Brash wants to reduce Maori representation – which will be less under SM and FPP - and then scrap the Maori seats.

That’s why Brash likes Supplementary Member and wants the Maori seats gone. Under First Past the Post he would never have been an MP as he admitted he would not have resigned from the Reserve Bank to be selected as a candidate.