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Small-Scale Question Sunday for September 8, 2024

Do you have a dumb question that you're kind of embarrassed to ask in the main thread? Is there something you're just not sure about?

This is your opportunity to ask questions. No question too simple or too silly.

Culture war topics are accepted, and proposals for a better intro post are appreciated.

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A question on voting. Ireland, where I live, uses the "single transferable vote" system. Irish people often favourably contrast it with the "first past the post" used in the UK. I was trying to explain the differences between the two to my girlfriend and illustrate the weaknesses of first past the post relative to STV. One weakness that jumps out even at a casual inspection is that first past the post massively incentivises tactical voting, which by extension likely gives a home advantage to incumbents. Are there any other significant weaknesses to first past the post? Conversely, are there any weaknesses to STV that make first past the post preferable?

There's a lot on this. First past the post isn't a very good system. See wikipedia on voting methods for an intro—there's a bunch of different desirable properties, only some of which are compatible.

  1. FPTP punishes smaller parties, meaning that the breadth of political belief in a country cannot be truly expressed. You'd better like the red or blue rosette parties, because nobody else really matters.

  2. If you vote for a smaller party, this punishes whichever of the main parties you support most. If you vote hard right, you get a left wing government, if you vote hard left, you get a right wing government.

  3. Governments can easily get 1/3 of the votes and 2/3 of the seats.

  4. FPTP rewards separatists, nationalists and regionalists disproportionately. The Nowherestan independence party can get 2-3% of the country-wide vote, and 10% of the country-wide seats because all their voters are concentrated in one region.

  5. Conversely, smaller parties with support that is spread out evenly across the country are punished. A party can get 20% of the vote and 1% of the seats.

  6. FPTP leads to major parties setting their opponents up to fail. In countries where coalition governments are normal, ruling parties have an incentive to act in the long-term interests of the country, as they could well be part of the government governing it for decades. In FPTP countries where power switches sides every few elections, ruling parties have an incentive to leave things in as bad a situation as they can, so that their opponents get blamed for it.

  7. FPTP leads to safe seats, which leads to individual MPs having less incentive to work hard or keep their views and policies responsive to the public.

I purposely used generic examples, but all of these things have happened or do happen in the UK.

Conversely, are there any weaknesses to STV that make first past the post preferable?

Eventually, parties start publishing "slates" which suggest to their voters the full order they should mark candidates in. Then it pretty much boils down to negotiation between parties for positions on each other's slates.

STV proponents assume that individual voters will have individual opinions on the different candidates. I.e. some Conservatives will put the Liberal party second, but others will put the far-right party second, and that proportion will determine the winner. But voting as a bloc is too strong a tactic. Very often an election will end up coming down to which parties can expect great fidelity to their slate.

So you end up with a vast increase in complexity and a great decrease in transparency, just to get the election decided by more backroom negotiation.

In Australia less than half of voters strictly follow their preferred party's official slate (how-to-vote card), though this is still enough to be important.

I would rather have negotiation between parties than the stonewalling we get here.

Plus, even if slates make STV converge on two parties, shouldn’t it break down more elegantly? By voting similar to the slate, you can tune how much you penalize the main party. That reduces the cost of coordinating a switch.

What do you consider a strength or weakness of a democratic system? Does the voter knowing the coalition that would come into power before the election matter? Does a leader having a majority of affirmation votes matter as a matter of legitimacy or political influence? Do party platforms that are harder to abandon on grounds of coalition negotiations count as a strength or weakness?

Different systems do different things, and the nature of the vote-counting is just part of it, as is the nature of the party structure itself. British FPP is based on a parliamentary party system in which there are strong parties and weak ministers who depend on the party to run on the ticket, which is a stark contrast to American FPP where the candidates are far more independent of party control.

Ultimately there is no 'best' system because any system has grounds for being criticized as flawed and illegitimate. Legitimacy is what people make of it, but there's no counter-argument if faith is lost.

The central problem with FPTP is similar parties. Splitting on a single issue is usually electoral suicide, forcing your supporters to choose between a genuine vote for your party or a tactical vote for the one which might actually hit plurality. The more similar, the worse. You can imagine splitting a 66% majority evenly and losing your seat to the remaining 34%. More realistically, it gives you “spoiler” parties which peel 1 or 2 percent off whichever big boy they hate the least.

This sucks! As a voter, you can’t express your first preference without actively hurting your second. As a politician, you can’t break with your party, because you will never be rewarded with success outside their envelope.

There are also effects on ideological coherence. “Big tents” of unrelated policy are encouraged because coalition building happens before voting. As a result, some bizarre issues have been coupled together for historical reasons, and now we’re stuck with them. I would argue it’s also less responsive than allowing coalitions to form within the government.

I feel it's unfair to compare FPTP to STV directly, because FPTP in the UK is used for single member constituencies, but STV is used for multi-member constituencies. I think it's the bigger and more important difference. A multi-member district is much less susceptible to gerrymandering (you can still do packing, which isn't a problem by itself, but cracking is much less efficient when there are four winners and instead of packing 49% into a district you can only pack 19% and can still lose a seat if your candidates aren't perfectly balanced).

However, STV is a pain to process. FPTP is "bigger pile of ballots wins", while STV requires a rather involved procedure where you have to keep track of a combinatorial explosion of expressed voter preferences or recount them multiple times.

First past the post is easily legible and, until the recent drop in voting plus new parties, made sure that the prime minister had been voted for by a near-majority of people.