A Field Guide to MMP, For People Who'd Rather Not

You get two votes. Most of the confusion about MMP comes from people trying to make it more complicated than that, so start there. One vote is for a party. One vote is for a person to represent your local electorate. They are counted separately, they do different jobs, and only one of them decides who governs the country.

It is the party vote. This surprises people who have spent thirty years being told all politics is local. Under Mixed Member Proportional, the share of party votes a party wins nationwide is, more or less, the share of seats it holds in a 120-seat Parliament. Win 40 percent of the party vote and you end up with roughly 48 seats. The electorate contests decide which individual humans fill some of those seats, not how many seats there are.

The mechanics are less painful than their reputation. Seventy-two of the seats belong to electorates, including the seven Māori electorates, and are won the old-fashioned way, by getting more votes in your patch than anyone else. The rest are filled from each party’s ranked list, topping the party up to its proportional share. If a party’s vote entitles it to 30 seats and it wins 20 electorates, ten list MPs come in behind them. The list is not a consolation prize. It is how the maths gets balanced.

There is a gate. To receive any list seats, a party must either win 5 percent of the party vote or win a single electorate. The second route is the famous one. Win one seat in, say, Epsom, and a party polling 3 percent nationwide brings a few colleagues into Parliament on its coat-tails. Entire strategies, and at least one widely photographed cup of tea, have been built on this rule. It has been reviewed repeatedly. It is still here.

Occasionally a party wins more electorates than its party vote entitles it to. Nobody gets evicted. Parliament simply grows to fit, which is why the House sometimes has 121 or more members and why this is called overhang, a word that sounds like a building defect and functions like one.

Then there is the part MMP is genuinely famous for: on election night, usually, nobody wins. Government belongs to whoever can assemble 61 votes in the House, which means negotiation, coalition agreements, and policy concessions announced with the warmth of hostage statements. Since the first MMP election in 1996 only one party has ever governed alone, in 2020, and the political system treated it as a meteorological event.

None of this was an accident. A Royal Commission recommended MMP in 1986, voters chose it at a referendum in 1993 after successive governments of both stripes did things nobody remembered voting for, and voters confirmed it again in 2011, with nearly 58 percent choosing to keep it. New Zealand looked at winner-takes-all politics and declined, twice.

So, a strategy for the reluctant voter. Your party vote sets the shape of Parliament. Spend it on the party you actually want, not a tactical guess. Your electorate vote picks your local representative and, in a handful of seats, doubles as a lever on the threshold rule. If you only have the energy to think hard about one of them, think about the party vote. It is the one doing the work.