Majoritarian Systems: Duverger's Law And Its Applicability

Duverger's Law is a theory in political science that claims that countries using 'majoritarian' voting systems will always have two-party politics. The law was proposed by French political scientist Maurice Duverger, who suggested that in the long run, rational politicians and voters will realise that it is futile to have more than two parties competing at the national level. However, Duverger's Law has faced criticism and is considered by some to be a dead parrot, with many European countries defying the theory and maintaining multiparty systems. This has led to a debate about why Duverger's Law now seems invalid.

Duverger's Law and the emergence of two-party systems

Duverger's Law, coined by French political scientist Maurice Duverger in the early 1950s, holds that countries using 'majoritarian' or 'first-past-the-post' (FPTP) voting systems will always have two-party politics. In other words, a simple majority, single-ballot system favours a two-party system.

Duverger's Law is based on the idea that, in the long run, rational politicians and voters will realise that it is futile to have more than two parties competing at the national level. This is because, in a plurality voting system, small parties are disincentivised to form as they have great difficulty winning seats or representation. Additionally, voters are wary of voting for a smaller party whose policies they actually favour because they do not want to "waste" their votes and so tend to gravitate towards one of the two major parties that is more likely to win a plurality and implement policy.

However, Duverger's Law is contentious and has been called a "dead parrot" by some political scientists, who argue that plurality or majority voting has no tendency to produce two-party politics. They point to the fact that many countries with FPTP voting systems have more than two sizeable parties, including the UK, Canada, India, and New Zealand.

While Duverger's Law may not be a hard-and-fast rule, there is some truth to Duverger's observation. Countries that use FPTP do tend to have fewer parties than those that use proportional representation, even if they don't always have true two-party systems. This is because, in a plurality voting system, it is difficult for third parties to win seats, as their support is often more evenly spread than that of major parties.

However, the ability of Duverger's Law to influence the electoral party system is questionable. Even in FPTP countries where nearly all seats are taken by the two major parties, it is common to see a sizeable chunk of voters opting for third parties. This suggests that not all voters feel pressured by FPTP to vote for one of the two main parties, and so support for third parties persists.

Additionally, Duverger's Law attributes to voting systems a power that they don't necessarily have. Parties tend to reflect the key divides in a society, such as class, religious/secular, or urban/rural. If these divisions are deep and cannot be reconciled, even the most constraining voting system may not be able to prevent the creation of multiple parties, as seen in countries like Scotland and India.

In conclusion, while Duverger's Law may provide some insight into the emergence of two-party systems, it is not an absolute rule. The voting system is just one factor that influences the overall party system, and a country with multiple cross-cutting cleavages may still end up with some degree of multi-partyism, even with FPTP.

The mechanical effect of First Past the Post

The mechanical effect of FPTP can be observed in the United States, United Kingdom, Canada, and India, where the Effective Number of Parties scores are low. This is because third parties that are successful under FPTP tend to have a strong base where the party system is somewhat detached from the rest of the country, such as the SNP in Scotland or Bloc Québécois in Quebec. In fact, FPTP can often overrepresent such parties if they achieve dominance in their respective region.

However, the mechanical effect of FPTP is not absolute. While it can shape the parliamentary party system, it does not always result in a pure two-party system. For instance, in the 2021 German election, the CDU/CSU and SPD took 88% of the FPTP seats on only 55% of the vote. Even with an historically low two-party vote, Germany’s several medium-sized parties were unable to take more than a handful of FPTP seats each because their vote distribution was not conducive to being the plurality winner in many places.

The psychological effect of First Past the Post

First-past-the-post (FPTP) voting systems, also known as plurality voting systems, are single-winner voting systems. In these systems, voters typically cast one vote for their favourite candidate, and the candidate with the largest number of first-preference votes is elected, regardless of whether they have a majority of votes.

FPTP has been criticised for its psychological effects on voters. For example, voters may feel pressured to vote tactically, choosing a candidate they think is more likely to win over their preferred candidate. This can result in a "wasted vote", where a voter's preferred candidate loses out because they chose to vote for a more popular candidate. This can also lead to false majorities, where a party wins a majority of seats in the legislature without receiving a majority of votes.

FPTP can also lead to spoiler effects, where the presence of a less popular candidate affects the outcome of the election between two more popular candidates. For example, in the 2000 US presidential election, the presence of left-leaning candidate Ralph Nader drew votes away from Democratic candidate Al Gore, resulting in a win for Republican George W. Bush.

FPTP has been criticised for its potential to encourage two-party systems, as voters are wary of voting for smaller parties that are unlikely to win. This can result in a polarisation of politics, with voters gravitating towards one of two major parties.

However, it is important to note that the effects of FPTP vary depending on the context, and other factors such as regionalism or coalition governments can influence the number of parties that emerge.

Duverger's Law in non-Western countries

Duverger's Law holds that in political systems with single-member districts and a plurality voting system, two main parties tend to emerge. However, this does not seem to be the case in non-Western countries, where Duverger's Law is observed to be less accurate.

In the UK, for example, while there is some two-party focusing, there is also a significant presence of smaller parties such as the Liberal Democrats, Scottish Nationalists, and Welsh Nationalists. In India, the two leading party blocs do not have a local majority, and there is a large number of seats where parties other than the BJP and Congress win or dominate local voting. Canada, which has a decentralised system of government, also has a multiparty parliament due to the growth of minor parties finding strongholds in specific regions.

Duverger's Law is also observed to be less accurate in Italy, where there is a slow shift towards two major parties, and Japan, where there is a slow trial-and-error process towards the expected outcome.

Overall, while Duverger's Law may hold true in some Western countries, it is less applicable in non-Western countries, where the presence of multiple parties and varying political contexts come into play.

Duverger's Law and the role of political parties

Duverger's Law, coined by French political scientist Maurice Duverger in the 1950s, holds that in political systems with single-member districts and a plurality voting system, two main parties tend to emerge. This is because voters are incentivised to vote for one of the two major parties that are more likely to win a plurality and implement policy.

Duverger's Law has been criticised for its lack of universal applicability, with many countries using first-past-the-post voting systems exhibiting multi-party politics. However, it is important to note that Duverger's Law is not a rigid rule, but rather a general guideline that is influenced by various factors.

One factor is the presence of strong local or regional parties that can gain a foothold in specific regions or constituencies, challenging the dominance of the two major parties. This can lead to the emergence of multiparty systems at the national level, even in countries with first-past-the-post voting systems.

Another factor is the existence of cross-cutting cleavages in society, such as class, religious/secular, or urban/rural divisions. If these cleavages are deep and cannot be reconciled, multiple parties may emerge to represent these differing interests, even in a first-past-the-post voting system.

Additionally, the mechanical effect of the voting system plays a role. In first-past-the-post systems, it is challenging for third parties to win seats as they need to be the most popular party in a specific region. This tends to favour parties with strong regional bases, such as the SNP in Scotland or the Bloc Québécois in Canada.

Furthermore, the psychological effect of the voting system on voters is also important. In theory, voters should be discouraged from supporting third parties in first-past-the-post systems due to the risk of wasting their vote. However, in practice, many voters continue to support third parties, indicating that the psychological effect is not as strong as predicted by Duverger's Law.

While Duverger's Law provides insights into the relationship between voting systems and party systems, it is essential to recognise that other factors, such as social forces and local dynamics, also play a significant role in shaping the political landscape.

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