First Past The Post is not the problem, districts are

It will come as no surprise to anyone that I am thoroughly against the systems used for electing representatives in both the UK and the US.

What may come as a surprise is that I’m pretty much indifferent to the fact that they both use first past the post, or simple plurality voting.

Don’t get me wrong. First past the post (FPTP from now on) is a rubbish voting system. It has essentially no redeeming values that are not also shared by approval voting, which is in all ways a superior system to it (I’m not massively in favour of approval voting, but it’s unambiguously better than FPTP). The point is not that FPTP is good, it’s that in this context it is irrelevant.

The reason it is irrelevant is that almost any choice of voting system in its place would produce just as bad or worse results, because the most major failure is in how we are applying voting, not the voting we’re doing.

To see this, consider the following scenario:

  1. We’ve got some geographical districts and each one gets exactly one representative.
  2. The representatives are divided into two parties. Call them the Purple and Green parties.
  3. The purple party has 50.1% of the populace who think that Purple is amazing and Green is literally the worst. The other 49.9% think the opposite.
  4. This division is uniformly spread over the entire country with little to no local variation

What happens? Well, you get an entirely purple house of representatives! Because in each district you have a strict majority of people who prefer Purple. Green gets exactly zero representatives despite the fact that 49.9% of the populace are strongly in favour of Green.

This is manifestly ridiculous, and the resulting government cannot be said to have any significant democratic mandate over an equally ridiculous 100% Green party. I’ll leave it up to you to decide how many more seats they should have than Green, but I’ll take it as read that getting all the seats is not an acceptable answer.

And getting this scenario required almost nothing about first past the post. If you replaced it with approval voting, alternative vote, range voting, whatever, the result would still be the same, because it boiled down to a simple majority vote and the majority in each district genuinely preferred Purple.

The choice of voting system influences what sort of distortions you can get. As your voting systems get better the above tends to be the only sort of distortion you get, but it will always remain possible. With districts, you can always take whatever single result you’d get if you ran the vote over the whole populace and just give them 100% of the seats by just spreading the population out this way (note: There are some technical conditions required for this to be strictly true, but it is in practice true with basically everything).

In practice the distortions are usually not this extreme because most of the time the distribution is not uniform. But that doesn’t make the result more representative of the populace, it just makes it a consequence of the vagaries of where people happen to live. You then get Gerrymandering happening, which is essentially the art of deliberately creating these distortions in a way that furthers your political aims.

The only way to avoid this problem altogether and also have districts is to have a system where some districts can genuinely have a majority preference for a candidate but that candidate still doesn’t get elected. This isn’t as unreasonable as it sounds. Two examples of reasonable ways to do this are random ballot and biproportional apportionment. However both of these are niche and you’re unlikely to get them.

Amongst systems with mainstream support, you really need to do away with districting in part or in whole. You need to move to a full proportional representation system across the whole country, or across larger multi-member districts.

But one thing you can’t do is just tinker with the system that you use in each district if you want to make a difference. Changing the voting system you use within districts is just rearranging deck chairs on the titanic, and continuing to focus on first past the post as a problem is just going to get you another vote on the optimal deck chair rearrangement at best rather than getting people off the sinking ship.

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