The Spoiler Wall

In elections under the First Past the Post system, there is a very well documented phenomena where parties of a similar ideology cannibalise each others votes. That is to say, two left wing parties existing in the same place, makes it easier for the right wing parties to win, because the left wing vote is split. This happens with the right wing too, as famously documented in the 2015 General Election, where UKIPs 13% vote led to the conservatives being unable to form a strong majority government, and UKIP only getting 2 seats out of that whole mess.

First Past the Post is a terrible system for many reasons, but the Spoiler Effect as it is called, is the biggest reason. If you vote how you truly feel and it isn’t one of the big 2 parties in your area, then the party you most hate benefits from that split vote. So any sane person would vote tactically, to ensure the party they most hate loses to the party they hate less but still don’t like. This eventually leads to a 2 party system like in the US, but the UK is special in the sense we have a 2.5 party system as some of my friends have called it. We still have smaller parties, its just that they never win power (besides that one time in 2010), and that is something to be proud of.

But there is a grim and truly upsetting truth of the Spoiler Effect. According to statistics published by YouGov, 20% of people tactically voted in the 2019 General Election. 20% of people were voting in a way that was not aligned with their interests or how they truly believe, and the system told them in a way, that if they voted for who they truly believed in, then they would only be helping the “enemy”. Now why is this so bad? Surely that 20% is substantial enough to sway an election, right? If that 20% decided enough was enough with the two top parties of the constituency they lived in, how much would that sway the election?

This is the leading groundwork for the main theory of this write-up. The Spoiler Wall. But first, let’s define an “electoral wall”. The Electoral Wall will be defined as the proportion of votes that must be swung from a party in order to lose 5% of the seats the party has,This is called a wall, because its to say that this much force from the electorate is needed to break it down, and show their distaste for a party. Losing just 1 seat isn’t a big deal, but losing 5% of your power in parliament shows a considerable disapproval for the largest parties in that system.

In a good, representative system, the proportion for a party to lose 5% of its seats, would be 2%. It makes sense and is fair in a republic democracy, if you lose 5% of your voter base, you should lose 2% of your power as you represent less people. Realistically, this will always be a little bit off, so we’ll say the ideal goal of a democracy is that if 6% lose faith in you, then you should lose 5% of your power. That’s nicely generous!

So what is that proportion in the UK? Now here’s our methodology. We’ll first be using the simulation system of this site to simulate the 2019 election as it happened, then use the “ALWAYS” functionality of the tactical voting modes to drain votes from the top two parties in each constituency. This includes the SNP in Scotland, the LibDems in some places, and Labour/Conservatives for basically everywhere else.

So the Conservatives had 365 seats in the 2019 election. 5% of that is around 18 seats. How much tactical voting needs to be corrected in order for the Conservatives to lose these seats? Remember, these votes wont swing to Labour in most cases, as you can read in our Simulation methodology article, but to Reform and the LibDems, and also independents, and also that their primary opposition loses their tactical votes too, so this should be a fair comparison. So how much of the Conservative voter base need to lose faith in the Conservatives to lose 18 seats?

32.1%

Let that number sink in.

For the Conservative Party to lose 18 seats, both them and their opposition in the constituency they are in must lose one third of their support to third parties. One third. This is simply not acceptable in a democracy. Again, their support base collapses by 33% in most constituencies and they STILL have majority control with 347 seats! This means that until a specific point, every vote that isn’t for the big parties is entirely wasted, and means nothing. Infact, what’s even worse, with the same methodology, the Conservatives only lose their 1st seat at 8.1%. And this isn’t even accurate! The seats oscillate back and forth between 0 and 1 seats until 16.7%. These are being lost and regained because of the odd few constituencies where Conservatives aren’t one of the top two parties, so they win a seat in those areas, but are losing seats in those where they are winning by a thin margin..

2.1% is this “Spoiler Wall”. It is the proportion of votes in First Past the Post that need to flow from the top two parties in a constituency, for the biggest party, the Conservatives, to lose 5% of their seats. 6% was our ideal goal here. The difference between that and 32.1% is astronomical, and even this isn’t enough to dethrone the top two parties in many places. Why was 5% chosen as the basis to find this wall? Surely it was more accurate to say that 16.7% is the wall, as this is when they first lost a seat and didn’t regain it? Well, it is because once this Spoiler Wall is hit, the amount of seats lost for every additional % of the votes being drained increases drastically, resulting in a Conservative minority at 34%, only 1.9% higher than what barely lost them anything. The Spoiler Wall is best defined as the “threshold where the systematic protections of first past the post begin to fail, and the party begins to suffer defeats which become increasingly more proportional to the loss of votes”

For the sake of comparison, I tested this under the Single Transferable Vote (Runoff) with an MP mode of “LIMIT” on County’s and 5 MPs, and the Conservatives with 2019 results (no tactical voting correction) wins 312 seats. The threshold is therefore about 16 seats. The Electoral Wall was found to be 6.5%. Under Proportional Representation using a Nationwide party list system, they win 283 seats, the threshold being 14 seats, and the Electoral Wall being found to be exactly 4.9%.

There are advantages to First Past the Post, and I am incredibly biassed against it and do not think the advantages justify us still using it, but I can recognise why people prefer governments without coalitions and think that the people should have to compromise. But frankly, I think anyone, even the people who defend this system, cannot see these numbers, and think that this is a fair democracy. Your voice doesn’t matter unless you live in marginal constituencies, where your vote counts, but even if you live in such places, if you like one of the smaller parties, then your voice still doesn’t matter. The truth is, that this system makes only a handful of people sway the elections, and even those people can’t express how they truly feel, because in these marginal seats, tactical voting is even more important.

The point of all of this is, the system we choose is so much more impactful on our voice than plenty of people think. Most people know voting for a smaller party is a waste individually, but to actually know how much of a strongarm tactical voting has over our politics is very scary. It boils down elections to simple competitions of Labour vs Conservatives, and who can scare the most voters into tactically voting against the other, and how to make the opponent look awful enough to make voters too apathetic to vote tactically.