A different MMP

A post by PaulL, commenter and occassional poster.

Noting DPF’s post on TPM overhang, I’ll make some comment on a proposal I saw on Twitter (X) from Liam Hehir. His point is that the overhang problem arises from having two votes, and from the potential of splitting those votes. He suggests keeping MMP, but going back to a single vote – your vote for your electorate MP would then be counted once in selecting the electorate, and separately for the party to elect the list.

It took a bit of thinking for me to see where he’s going with this. It would mean that you can’t have a party that gets lots of electorates (therefore lots of electorate votes) but very few list votes – since they’re the same vote. No doubt the numbers could still throw up some small anomalies, but it’d be a hell of a lot closer.

The downside would be if you are looking to vote for a minor party that has no chance of winning your local electorate. For example, you live in Rangitikei but like ACT. You can still vote for your local ACT candidate (thereby giving ACT your list vote), but they have no chance of being elected. You effectively would get no say on who your local MP is.

My proposition to extend his would be to allow a form of STV as well. This would mean:
1. You have one ranked vote. Your #1 pick for electorate and for the party need to be the same. In my example above, in Rangitikei you rank ACT and Andrew Hoggard #1

2. You can then rank electorate candidates as you see fit. So you might rank the National candidate next, then NZF etc

3. If your #1 electorate candidate is eliminated then your electorate vote goes to your second choice and so on

4. If your #1 party don’t make the 5% threshold, then your party vote would move to the party of your second ranked electorate candidate.

From a voter perspective, you just rank your electorate candidates (and their parties) in the order you like. It’s relatively easy (but still more complex than a single vote). From a counting perspective it’s a pain, but that’s what computers are for. In a proportionality sense, I think it becomes hard to end up manipulating things to create an overhang – your electorate and list vote are now tied together.

Overhang is only created when your electorate vote elects an electorate candidate to whom you didn’t give your party vote. This prevents that scenario – if your #1 candidate gets elected, then by definition they have met the threshold, so your party vote will go to the same party. There’s maybe a scenario where, in an electorate, lots of people give their #1 vote to an ACT candidate, and their #2 vote to TPM. TPM get no party votes, but their electorate MP could still get in. However, in that scenario it seems to me that it’s suddenly likely the ACT candidate wins the electorate – it would be very hard to reliably game this.

Of course, another option is to just change to STV with multi-member electorates. It gives a similar result, with a bit more of a bias towards larger parties, which isn’t necessarily bad.