Does First Past the Post stop extremists getting into parliaments?

If you listen to supporters of first past the post, you might be forgiven for thinking that British voters are just itching to elect dozens of far-left and far-right MPs. For them, continuing with a voting system that ignores millions of voters is a price worth paying to defend parliament against hypothetical votes from an imagined future. The problem, though, is that the idea that the current first past the post system prevents political extremism isn’t something that stands up to scrutiny.

It is undoubtedly true that PR allows for higher numbers of MPs from ‘non-mainstream’ parties – most European parliaments contain at least one left-wing socialist and one right-wing populist party. But the lack of such parliamentary parties under First Past the Post isn’t the same as those ideologies not being there. Within two-party systems, the different political parties of a multi-party system simply get squashed as factions into the two ‘big-tent’ parties.

Britain may not have a sizeable left-wing party, but there is undoubtedly a faction of Labour that has a greater affinity towards Germany’s far-left Die Linke than the centre-left SPD. The Conservative Party may view itself as a bastion of moderation, but it did eschew the centre-right EPP Euro-party in favour of creating the more right-wing ECR. And, in the 1970s, the far-right Monday Club had around three-dozen Conservative MPs as members.

As each party only puts up one candidate, moderate voters for either party can, unknowingly, vote for a candidate more extreme than they would like.

When taking into account such factions, the British party system doesn’t really appear to be much more moderate or centrist than that of most other European countries. But can we put a number on it? Well, using data from the Chapel Hill Expert Surveys – which attempt to measure the positions of European parties on various issues – we can create a ‘Deviation from Centre’ index which measures how far each party is from the political centre and weights it according to its share of seats in parliament.

Here, we have applied the DfC index to the five most recent parliaments in each western European country and taken an average. A score of 0 would indicate parliaments wholly made-up of perfect centrists, while a score near to 5 would suggest parliaments that were entirely comprised of some combination of the extreme-left and extreme-right.

Chart 1: Average Deviation from Centre Score of Western European Parliaments.

Great Britain’s score does not contain the 18 Northern Irish MPs

What’s most clear is that there is fairly little variation between countries. There is a small cluster of super-centrists (primarily Luxembourg and Ireland) and then there is Switzerland’s unusual party system as an outlier at the other end. But most western European parliaments generally fall somewhere around the 2.0 mark.

But Britain’s middling average hides the significant level of variation between elections caused by the fluid nature of the ideology of our two main parties. The average variation between the highest and lowest DfC scores for the other 13 countries is 0.57, with the highest range being France (0.93). But Britain’s range over the last five elections is 1.76, with the strong centrism of the New Labour era pulling down Britain’s average. Looking at just current parliaments, Britain actually returns the third highest score (2.35) – behind only Belgium (2.64) and Switzerland (2.66).

It’s also important to note that Britain’s DfC score is almost entirely made-up of the two main, governmental parties. But, for many proportional countries, those parties that are too left or too right are subject to a ‘cordon sanitaire’ – whereby the mainstream parties refuse to allow them into government. If we reapply the DfC index to cover only governmental parties, we can get a better look at the ideological strength of the parties that are actually allowed near power.

Chart 2: Average Deviation from Centre Score of Western European Governments

Here, we see even less variation than with overall parliaments, with most of western Europe scoring between 1.65 and 1.90. Unsurprisingly, most countries see a notably lower score – though Britain’s difference is negligible. And again, our average is being pulled down by earlier ministries – only Switzerland’s government currently has a higher DfC score than Britain.

Overall, the variation between countries in the net extremeness of their parliamentary parties is fairly small – with many of the differences that exist being more attributable to a nation’s political culture than its voting system. The only systems that have a demonstrable effect on such matters are preferential systems like the Single Transferable Vote, where less moderate parties often find it difficult to gain the second preferences needed to win seats.

It is simply untrue to suggest that proportional representation inherently leads to ‘more extreme’ parliaments or governments. While it may lead to greater representation of non-‘mainstream’ parties, those that are viewed as unsavoury or extreme are largely excluded from power. Something that cannot be said of First Past the Post when major parties, such as the US Republicans, are taken over by political extremists.