1 Dissecting the question
Before going further, the question indicates a problem. By asking, why are Japanese political parties so similar, it suggests that political parties are similar, this ignores divisions and nuance between the parties. There are differences between the Japanese political parties, most explicitly the surrounding Article 9 of the Japanese Constitution, also known as the “peace clause,” Japanese pacifism and security policy, and the US-Japan Security Treaty’s provision for US bases. Increasingly, whilst similarity exists, it is not extreme to where each party is simply a copy of another, similarity, and difference both exist. Kubo argues that one “single dimension” cannot explain all areas of similarity or difference (Kubo, 2022, pp.261). Kubo’s scholarship notes the difficulty of using one theory to account for Japanese politics. However, Kubo’s quote can also relate to how party similarity may be more complex than one single answer such as electoral reform or rational choice theory. Therefore, rational choice theory will account for the main body of this essay, however, structural realism will be deployed as well and the Japanese state also displays ideas of liberalism, however, this will not be explained exhaustively. Plus, whilst electoral reform and rational choice theory give reason for party similarity, there may be long-term factors that also tie into this argument that have not appeared or been adequately researched yet. Thus, political parties are similar, but there is difference and cleavages present too.
2 The current makeup of political parties in Japan
Political parties in Japan are similar because of electoral reform in 1994, in which parties pursued electoral reform because of the rational incentive for success. There are eight different political parties in Japan, most influentially, the Liberal Democratic Party (LDP). The Liberal Democratic Party was in power from 1955 to 1993 when factionalism and breakaway parties caused the LDP to decline. Alongside the LDP, the Japan Innovation Party (JIP) is also right wing. The Democratic Party for the People (DPP/DPFP), the Komeito party and the Constitutional Democratic Party are all centrist. Currently, the ruling government consists of the LDP and the Komeito party, they have been in a coalition since 2012. The Komeito and the LDP are a good example of the similarity that exists within Japanese politics, this is because even when the LDP and Komeito aren’t in a coalition, they “have cooperated consistently” between 2000 and 2017 despite being “ideologically incompatible” and pre-coalition “sworn adversaries” (Liff, 2018, pp.54). The cooperation between the LDP and Komeito party demonstrate similarity and the benefits. Rational behaviour has allowed the two to govern Japan for over 10 years. Thus, to sustain a majority, the two parties will need to agree, demonstrating unity rather than fragmentation. The political parties occupy familiar positions on the political compass; however, these positions are likely to change to a more evident conversion into the center because of the rational incentives to appeal to voters. Kubo further notes that parties in Japan do not distinguish themselves clearly and they often change the importance of their policies (Kubo, 2022, pp.260). Therefore, any ideological groupings may shift because of parties’ motivation to adapt to voter preference.
3 Rational Choice Theory
Rational choice theory (RCT)assumes that “Individual behavior is motivated by self-interest, utility maximalization” and “goal fulfillment” (Petracca, 1991, pp.289). Taken from Adam Smith (1775) in Petracca’s work, “he will be more likely to prevail if he can interest their self-love in his favor” (Petracca, 1991). Smith’s quote shows the importance of self-interest to rational choice theory. RCT is deductive of politics, it emphasizes the individual and rationality to predict the outcome of political events. Rational Choice Theory is normative and has an empirical nature, relating it easily to the political world. Rational choice theorists would argue that parties will develop policies to attract median voters, as the main goal is to produce a government. This rational thinking is what caused the LDP and smaller parties to pursue electoral reform in the first place. By attempting to attract swing voters, parties will tend to converge within the center, as displayed by the Democratic Party for the People, the Komeito Party, and the Constitutional Democratic Party. The Komeito party benefits from this center positioning as illustrated by the current coalition government. Plus, in the 2009 general election, the Democratic Party of Japan campaigned with on the basis that it was “Not the LDP” resulting in a landslide victory with a win of more than three hundred seats (The Japan Times, 2009). This campaign message of anti-LDP by the DPJ is ironic because the DPJ consisted of former LDP members because of factionalism, plus, both parties adhere to concepts of liberalism. Within the Japanese setting there have been clear displays of rational choice theory, causing the theory to be valuable.
（1）A feminist critique of Rational Choice Theory
Rational choice theory is beneficial regarding incentives, but like any other theory RCT has been susceptible to criticism. A prevalent critique is that RCT is too simple and does not consider the “complexities of human nature” (Petracca, 1991, pp.289). A feminist-based critique follows that rational choice theory “uses concepts informed by patriarchal assumptions” thus, excluding women from political thought (Driscoll, 2012, pp.201). Smith’s own writing proves this feminist critique as the use of male pronouns, ‘he,’ suggest that only men are capable of rationality. Although the feminist claim is valid, this does not reduce the effectiveness of RCT. Plus, women’s participation in political thought has increased since the Enlightenment era. The idea that women are not capable of rationality but only emotion is a reoccurring problem running throughout enlightenment thinking and does not have any scientific grounding. Thus, although RCT has gained criticism within the scholarship, it is still compelling in the case of Japanese political parties, this is because of the theories applicability to reality. RCT is a motivator for parties who want to be successful, leading to similarity across the political spectrum.
4 Electoral reform in 1994
In 1994, electoral reform resulted in a new mixed-member system (MMM) consisting of a single-member plurality (SMP) voting system and a Proportional Representation (PR) system. In this new system of MMM, the electorate has two votes, one for an individual representative and another for a political party (Shiratori, 1995, pp. 88). The mixed system means that both smaller parties and larger parties’ benefit, producing rational incentives for reform from all sides of the spectrum. Reform in 1994 also involved party subsidies and finance regulations because of the monetary scandals that previously plagued the Liberal Democratic Party. Finance regulations resulted in disclosure limits lowered to 50,000 yen and a ban on donations from unions (Carlson, 2022, pp.5). Curtis rightly argues that “the situation that emerged in the 1990s is different” because of the new reforms, the end of the ’55 system and the collapse of the bubble economy, causing parties to operate “within the same ideological space”, such as the center (Curtis, 2004, pp.226). The new MMM system “reduces the difference” between the political parties as it is not rational for parties to put themselves on “one side or the other of such a dividing line” for example, parties placing themselves on ideological extremes (Curtis, 2004, pp.237). Thus, the new electoral system increased policy convergence, constructing similarity.
（1）Corruption as an incentive for electoral reform
A significant reason for the electoral reform in 1994 was the LDP attempting to create a cleaner image coinciding with rational incentives to ensure party dominance. The LDP “first started the argument for political reform” according to Shiratori, demonstrating that the LDP had a contending role in this reform (Shiratori, 1995, pp.92). Scholars such as Reed, Hirano, Shiratori and Thies note the LDP’s role in pursuing electoral reform because of the scandals within the party. Examples of corruption include the Lockheed Bribery in 1976, The Recruit Scandal in 1988 and the Sagawa Kyubin in 1992. Corruption was frequent in the LDP, despite the party website emphasizing “democracy” and “positive contributions,” scandals still exist today (Liberal Democratic Party, 2023). The Asahi Shimbun records four incidents that have hit the LDP recently, the voter buying scandal in 2019, the Sugawara scandal and the Kentaro Sonoura scandal in 2022 (The Asahi Shimbun). Electoral reforms have not stopped the occurrence of corruption within the LDP, as since the 1990s, opinion polls have demonstrated voter complaints (Thies, 2001, pp.156). Prime Minister Toshiki Kaifu received an approval rating below 40% during the 90s, depicting the need for reform because of the levels of voter unsatisfaction (IPU archive, 1990). Because of the corruption in the LDP resulting in low levels of voter confidence, the LDP had to pursue reform to appear less fraudulent, displaying tenets of rational choice theory in attempts to remain dominant in government.
（2）Smaller parties pursuing electoral reform
The role of smaller parties in pursuing electoral reform was another display of rational choice theory. “Strategic motivations” drive smaller parties to “maximize” their political power, attempting to dislodge the LDP from its dominant seat (Pilet, 2011, pp.577). Whilst the new electoral system, specifically proportional representation, is beneficial for smaller parties because of “dual candidacy” and “best loser provision” the previous SNTV system severely disadvantaged smaller parties (Huang, 2016, pp.30) (Hirano, 2006, pp.60). Huang argues that smaller parties were a victim of the electoral system, which seems evident. Smaller parties suffered because of factions, corruption and money politics that existed in the old system, however, such issues are also prevalent under MMM (Huang, 2016, pp.30) (Hirano, 2006, pp.60). The success of smaller parties is higher in the MMM system. The Komeito party demonstrates success, in 2021 the party won seven million votes in the proportional vote. Therefore, despite different rational motivators behind smaller parties and the LDP, both want to increase their voter power share which produced consensus on the need for electoral reform.
（3）The impact of the MMM system and geographical dominance
The impact of electoral reform in 1994 resulted in the diffusion of geographic dominance, significantly regarding the LDP, further facilitating similarity as the dominant party had lost its once secure voter base. The LDP under SNTV was known to dominate rural areas in comparison to urban seats, creating a strong relationship between the LDP and farmers (Curtis, 2004, pp.44). SNTV gave way to geographic domination because of the one-party system it endorsed based off individual centered campaigns. The MMM system weakened geographic support by turning the 129 districts into single member districts. Under MMM, parties’ ability to dominate “rural districts” decreases, causing “electoral volatility and cohesiveness” to increase, resulting in an influx of median voters, causing parties to shift to the center (McEwlain, 2012, pp.344). Increasingly, the weakening of geographic affiliation means that indicators of voting behaviour have changed, as Curtis notes that party affiliation is now determined by “prospects for electoral success” rather than ideology (Curtis, 2004, pp.228). Therefore, McEwlain notes that nationalization of elections and a two-party system have caused “regional dominance” to erode (McEwlain, 2012, pp.337). The lessening of rural domination means that the LDP has suffered a setback, this could cause one to argue that pursuing electoral reform was not the most rational decision the LDP could take. Although the LDP’s rural dominance reduced, the LDP is still the dominant party in Japanese politics as it is currently in government, despite a current coalition. Thus, the LDP has a reduced voter share in comparison to pre-1994. Therefore, the lack of regional dominance by the LDP or any other party rurally, means that smaller parties have a larger possibility of forming a government, as parties compete for the same sub-set of median voters.
Although rational choice theory can be successfully used to explain political outcomes, in the case of the Komeito party, the party acts as an “anomaly” to theoretical understanding and to coalition politics (Liff, 2019, pp.57). The Komeito party’s strong religious support base differentiates the party from others within the Japanese political system. The Soka Gakkai is a Buddhist group that has strong ties to the Komeito party, creating a solid support base. The religious group gives reason for the Komeito party’s difference that may not be substantiated by rational choice theory. Firstly, the Soka Gakkai strongly supports the Komeito party, no other Japanese party has such a strong support base, the Nippon Kaigi does not necessarily compare either. Secondly, Liff notes that fact that in some single member districts, the Komeito party does not put forward a candidate but mobilizes “its exceptionally loyal support base” which is the Soka Gakkai (Liff, 2019, pp. 56). Thus, the Komeito and the LDP have an agreement to ensure the longevity of their coalition, in which members of the Soka Gakkai also vote for the LDP. The actions of the Komeito party are unusual and it is questionable if such behavior can be explained by RCT. Liff argues existing theories “struggle to explain the durability of a puzzling” coalition like the relationship between the LDP and Komeito (Liff, 2019, pp.58). The Komeito party is not demonstrating the key tenets of rational choice theory as it does not attempt to maximize its voter share or appeal to the whole of the electorate. However, Liff argues that “incentives” created by “Japan’s mixed electoral system” acts as the reason for Komeito’s odd behaviour, in which the two parties would be worse off if a coalition was not formed, at least Liff’s scholarship makes it out to be this way (Liff, 2019). Therefore, the actions of the Komeito party do not display strong rationality but do not demonstrate irrational behavior either. Thus, there is a need to apply a different theoretical framework when analyzing the role of the Komeito party in the Japanese political system.
5 An area of difference
（1）Article 9 “The Peace Clause”
The ’Peace Clause’ or Article 9 of the Japanese Constitution and its implications for Japanese security policy serve as an area of significant disagreement within Japanese society. The debate acts as an area of nuance because of the polarization that military issues attain in Japan. In Article 9 of the Japanese Constitution, titled the ‘Renunciation of War,’ the document commits Japan to “an international peace based on justice and order” renouncing the use of force as a means of settling international disputes (Constitution of Japan, 1947). The Peace Clause is a prevalent issue for parties and in public opinion. Specifically, the LDP has advocated for “revision since the party’s formation,” while the Komeito party has gradually become more open to constitutional reinterpretation and or revision by its more dominant coalition partner, the LDP(CFR, 2023). The Japan Innovation Party (JIP) and the Democratic Party for the People are also pro-revision. The Constitutional Democratic Party of Japan, however, oppose revision, alongside the Japanese Communist Party and the Social Democratic Party and Reiwa Shinsengumi (The Asahi Shimbun, 2022). However, within this pro-revision grouping there are more complicated disagreements regarding different opinions on what should be changed and how. It seems that “only the LDP” is willing to reform the language of the Peace Clause (CFR, 2023). The Asahi Shimbun reports how 52% of citizens think the constitution should stay the same, however 37% disagree and advocate for reform instead (Teramoto, 2023). Furthermore, the 2023 survey reported the lowest levels of positive views of the constitution since 2013 (Teramoto, 2023). The debate surrounding the Article 9 is informed in part by the fact that despite the pacifism Japan’s constitution commits it to, Japan nonetheless possesses significant military power. Business Insider ranks Japan’s Self Defense Forces as the 8th most powerful military force in the world as of 2023 (Baker, 2023). Japan’s Self Defense Forces possess more than “900 warplanes, 48 destroyers and 20 submarines”, numbers which exceed major military powers such as the United Kingdom, Germany and Italy (The Asahi Shimbun, 2021).
This has led some to question how Japan’s pacifist constitution has enabled the procurement of such a formidable military force (Harvey, 2008). That contrast, between the pacifism enshrined in the constitution and the reality of Japan’s well equipped Self Defense Forces has stimulated debate among political parties and the Japanese public.
（2）The US-Japan Treaty and Okinawa
The debate surrounding Article 9 and Japanese security policy links to another area of contestation, the presence of US military bases in Okinawa because of the US-Japan Security Treaty. The US-Japan Security Treaty of 1951, titled “The Treaty of Mutual Cooperation and Security between the United States and Japan” faces criticism due to the treaty’s permittance of a large US military presence in Okinawa, although there is not substantial debate around the treaty itself (MOFA, 1960). Okinawa is an island off the Southwest Coast from mainland Japan, the island is home to two US bases, Fuetnma and Kadena. Okinawa is one of the smallest and poorest of Japan’s prefectures, causing further contempt. Okinawa has an area of 463 square miles The US bases on Japanese soil expand US’s military umbrella, protecting Japan. Increasingly, there are more US military personnel stationed in Japan than any other country, with just over 60,000 as of 2021, specifically within Okinawa (Maizland, 2021). Reporting by the Asahi Shimbun on a survey conducted in 2022 suggests that while a plurality of Japanese (46%) are in favor of reducing the burden of US military bases on Okinawa, a strong majority (69%) of Japanese believe that US bases in Okinawa “are necessary for the security of both Japan and the United States,” and an even larger majority (82%) support the continuation of the Japan-U.S. Security Treaty. Thus, while debate exists, its contours are much narrower than the wide divergence of opinion that exists surrounding any potential revision to Article 9 of the Japanese constitution. The data clearly shows that while the public is sympathetic to reducing the high burden borne by Okinawa, support for both the security treaty and US military bases in the prefecture remain relatively high.
（3）The Anpo protests
The Anpo protests depict the historical political polarization that existed surrounding the US-Japan treaty, although such divergence no longer exists, suggesting that Japanese society is not as polarized as it used to be. The Anpo protests were a series of large protests in the 1960s and 1970s against revision of the Security Treaty between the United States and Japan. The protests illustrate the divergence that existed within Japanese society, particularly in the beginning of the 1960s. Shimabuku notes the Anpo protests as “the most significant moment of mass protest in the history of postwar Japanese activism” (Shimabuku, 2019, pp.94). Kapur also goes on to suggest as much as one-third of Japan’s population at the time participated in the Anpo protests (Kapur, 2018). The Anpo protests displayed the wider public dissatisfaction with the Japanese government, not just the resistance to the security treaty with the United States and US military bases in Japan. The Anpo protests, despite happening 63 years ago, depict the long-term disagreement that exists, specifically in relation to US bases on Okinawa that is still a problem for some citizens today, acting as an area of nuance in this debate concerned with a difference between state level actors and citizens.
（4）Structural Realism and the Peace Clause
The debates that exists surrounding Article 9, Japanese security policy and to a lesser extent, US bases in Okinawa, cannot be understood purely by rational choice theory. This is because there is an apparent lack of rationality displayed here due to the divergence between public opinion and policies pursued by political actors. It could be argued that political parties are not successfully implementing the will of the voters specifically surrounding security policy. This means that parties are not maximizing their voter share. Structural realism (aka neorealism), coined by Kenneth Waltz find that states act the way they do because of the anarchic nature of the international system which forces their primary concern to be their own security. Thus, structural realism argues that states act based on “suspicion, power and force” (Antunes, 2018). Japan, however, does not necessarily act through military hard power like Russia, but instead tends to rely more on the strength of its economy, combined with the soft power generated through Japanese culture and exports, potentially weakening the relevancy of structural realism here. Nonetheless realists might argue that the stances taken by Japanese political parties on US bases in Okinawa tie back to structural realism. Given Japan’s reliance on its alliance with the US for its security, even if voters wished to remove US Military bases, this move could strain ties with the US and risk endangering Japan’s national security. Therefore, most political parties opt to work ambiguously towards reducing 'Okinawa’s burden' in alignment with US interests. One could perhaps go a step further and even argue that Japanese political parties are behaving like state’s in the international system, attempting to ensure their survival and maximize their vote share, by pursuing electoral reform while avoiding a confrontation over US Military bases in Okinawa that they cannot win. Another international relations theory, Liberalism, emphasizes cooperation and collaboration between countries through international organizations such as the United Nations. Again, one could argue this resembles the preference of Japanese political parties for coalitions (peace) rather than competition, and is perhaps most exemplified by the LDP-Komeito partnership.
（5）Structural realism and the US-Japan Treaty
Neorealists would explain the US-Japan treaty alliance as an example of the US ensuring stability within the international arena as the main hegemon. The US has ensured stability through coercion, according to structural realism. Japan faces “external threats” geographically, its neighbors consist of North Korea, China, and Russia, causing Japan to grow more dependent on the US (Katagiri, 2018, pp.326). The concept of the balance of power is integral to structural realism, linking to the US-Japan treaty as an example. The balance of power argues that when state power is even there is peace, disruption to the balance creates disorder and threatens war. The US-Japan treaty is an example of the balance of power and attempts to preserve it, ensuring the survival of the Japanese state. The scholarship from Katagiri further advances the linking of structural realism to Japan, arguing that “a single theory” cannot understand all of Japan’s perceptions and threats (Katagiri, 2018, pp. 327). This is why Katagiri makes use of structural realism and liberalism. Japanese pacifism and Article 9 of the Japanese constitution may at first seem inconsistent with realism at first, however, a deeper examination reveals realism can in fact explain this behavior. Japan demonstrates the balance of power “both internally and externally” according to ideas within structural realism, especially regarding Japan’s relationship with the United States (Katagiri, 2018, pp. 328). Although the Article 9 is a commitment to pacifism Japan’s military strength is evident, demonstrating how although domestically political parties play to ideas of rational choice, in the international arena, Japan uses structural realism, suggesting why this is an area of divide rather than unity.
（6）The domestic realm and theoretical limitations
Although structural realism has been used within this essay to speculate on the role of the Article 9 and the US-Japan treaty within Japanese domestic politics, structural realism, as a theory of international relations focused on explaining the behavior of state actors in an anarchic international system, has only limited capacity to explain the behavior of domestic actors such as political parties. This is because, unlike in international relations, domestic politics is not an anarchic system, there are laws, checks and balances and judicial systems that regulate what parties can do and mediate relations between them. Thus while structural realism can explain why the country of Japan, as a singular political entity, pursues certain security arrangements, and thus suggest why domestic actors may find these options attractive or even inevitable, only rational choice theory can truly account for and explain the choices of political parties and individual decision makers within them. That said, understanding the broader context of international relations and Japan’s choices within it through structural realism allows for a more nuanced application of rational choice theory in examining the question of why Japanese political parties are similar.
6 The cost of consensus for voters
The implications that party similarity has on voters remains unclear back of the lack of research and scholarship here. Therefore, we can hypothesize that the effects of party similarity on voters can correlate to low voter turnout. Low voter turnout is depicted in the high turnout rates before the 1994 reform, from 1946-1993. Voter turnout rates dipped dramatically in 1995, falling to 44.5% in comparison to the 67% voter turnout two years prior (IDEA, 2023). However, turnout rates have managed to increase slightly during 1996-2009, but the dates from 2012 onwards are lower in comparison. Party similarity may also affect voter satisfaction, as the Asahi Shimbun reports how voter satisfaction was low with 47% of those in their thirties having no interest in politics (Watanabe, 2023). Voter apathy is another cost of this consensus, a 2019 survey reported that voters were not “motivated by economic or social values” causing them to be uninterested in politics (Yamaneko Research Institute, 2019). The YRI argue that more prominent issues, such as the Article 9, have a prominent role affecting voting behavior in the 21st century. Thus, party similarity has a negative impact on the electorate as suggested by lower turnout and voter satisfaction but also increasing voter apathy.
（1）The scholarship of Liff regarding turnout
The cost of consensus on voting behavior impacts turnout, voter loyalty and confidence as parties collaborate and demonstrate similarity. Liff’s scholarship is increasingly valuable here due to their findings on voting behavior which suggest that voter identity has become more “fluid” or even “absent” (Liff, 2018, pp. 61). Liff’s work suggests that voter loyalty is decreasing prompting the likelihood of the median voter. According to rational choice theory, parties appeal to the median voter, causing party similarity to increase with an alignment to the center. In 2009, the Democratic Party of Japan won the election creating a strong majoritarian government, this caused the LDP to lose a dedicated support base (Liff, 2018, pp.61). Political parties will have to make themselves and their policies more appealing because of the influx of swing voters. Party similarity in Japan is a modern phenomenon that is still ongoing, therefore, the impact that party similarity will have on voters is unclear due to the long-term implications of this issue, however, the forecast seems negative.
7 A Comparative case study, The UK
The similarity that exists in Japan is distinct to the political system in the United Kingdom. The British parties are more extreme in comparison to Japan, as British parties occupy opposing ideological spaces to appeal to a polarized and ideologically divided electorate. Using Japan within this comparative case study displays the unique nature of similarity among political parties. As mentioned throughout, Japanese political parties because of the electoral reform that occurred in 1994 to a mixed multi-member system and the rational incentives that similarity provides. However, there has been no structural reform in the UK to constitute such a difference or similarity. This begs the question of if electoral reform facilitated similarity among Japanese political parties, then what has caused British political parties to be so different, the answer is issue politics, significantly Brexit.
（1）An example of similarity
However, in British politics alignment to the center has occurred before. Most notably, in 1997, when Tony Blair the leader of the Labour party in the UK won a landslide election by shifting the Labour party to the center instead of to the left. The Labour party gained 146 seats whilst the conservatives lost 178, this illustrates how the convergence of parties to the center is rational because of the incentives it provides (BBC, 1997). Therefore, there is resemblance between the two countries but not explicit similarity.
（2）British Political Parties
In the UK, there are a plethora of political parties, thirteen to be exact, they all occupy different spaces on the political spectrum. The Green party is currently the most leftist, the Liberal Democrat party who are center-right and the Labour party who surprisingly in the 2019 general election that shifted to a right-wing space alongside its main competitor, the Conservative Party. The System of First-Past-the-Post in the UK means that a party needs to receive one more vote than all the other parties. This electoral system has created a two-party system between the Conservative party and the Labour party, creating alternating governments. One could argue that there is a one-party system in the UK due to the dominance of the Conservative party since 2010. However, this is not the case, as historical context demonstrates that the Labour party and Conservatives have governed equally since 1922. The differing positions of the political parties demonstrate the division of the British electorate that the parties are attempting to appeal too.
（3）Brexit as a source of polarisation
British society is divided in comparison to Japan, significantly regarding issue politics, most famously, Brexit. Brexit is the name given to the UK’s withdrawal from the European Union. Despite the referendum in 2016, the UK did not formally leave the EU until 2020. Brexit acts as a source of argument, specifically surrounding the outcome. 51.89% voted in favor of leaving the EU, whilst 48.11% wanted to remain. The results indicate an exceedingly small margin of difference which prompted a call for a re-vote. The need for a re-vote suggested that the answer of ‘leave’ was not the ‘correct’ answer. Increasingly, the outcome distinction between countries in the UK also prompted calls for another referendum with Scotland and Northern Ireland voting to remain and England and Wales voting to leave. However, the population count of England is much larger than that of the other countries, making the English mandate to ‘leave’ stronger. Despite this, the referendum outcome displays how divided British society is and will continue to be.
（4）Voting behaviour in the 2019 UK General Election
The British electorate division on salience issues facilitates difference in comparison to the Japanese case study. The importance of salience issues such as Brexit has caused British political parties to be different instead of displaying similarity, especially as specific parties have tended to appeal to a certain voter type. Historically, the Conservative party addressed upper-class, white, old people who live in the countryside or affluent areas. In comparison, the Labour party appealed to the working class, unions, young people, and those who live in urban areas. However, in the 21st century it seems as if the party’s distinct voter type has flipped. This means that currently, the elites support the Labour party whilst the working class support the conservatives. The 2019 general election reflected voting behaviour change and the Brexit vote whether the electorate wanted a hard Brexit, vote conservative, or a soft Brexit, vote Labour. A YouGov survey demonstrates that “class is no longer a key indicator how people vote” as the Labour party in the 2019 general election performed the same among ABC1 and C2DE (McDonnell, 2019). However, the data presented by McDonnell does slightly support the hypothesis that voting behavior has flipped. This is because the Conservative Party “did better amongst C2DE voters (48%) than they did amongst ABC1 votes (43%)” (McDonnell, 2019). This suggests that class is becoming less of an important indicator of voting behavior within the UK. Thus, demonstrating the ongoing impact of voter identity on political parties.
The scholarship of Jennings revealed a “country divided by place,” however, multiple factors tied into the voting behavior of the electorate within the Brexit referendum (Jennings, 2019, pp.155). Jennings argues that the division in most categories of identity is because of long-term trends. The scholarship provided by Jennings is increasingly specific, as he notes social and economic trends that drive difference, Jennings specifically notes geographic polarization. However, drivers of polarization include economic divergence, education, immigration and changing class structures. This disagreement has implications for voters, with only 23% of the electorate trusting the government to put the needs of the nation first and only 10% trusting politicians to tell the truth (Common Library Research Briefing, 2022). This suggests that regardless of party similarity or difference, a like to the case in Japan, the electorate are becoming less interested in politics. The low rates of voter trust for politicians means that political disengagement is extensive within British political society, consequently causing extreme divergence as a result.
（6）The long-term costs of Brexit
Although Brexit may no longer has a role within British politics since the formal exit from the EU in 2020, the succession has created long-term impacts for the British electorate. The issues that the UK currently face is stalled investment, shortage of workers, cost of living crisis, strikes and rising inequality (David, 2023) (Cookman, 2023). The extent of the issues created by Brexit continues to further divide British society . Issue politics like Brexit has caused British political parties to be different in the 21st century. The historical examples of party convergence in the center in the UK are no longer valid. It is evident that the median British voter sits on the right, facilitating difference.
In conclusion, Japanese political parties are similar because of the electoral reform in 1994 but also because of the rational incentives that parties gain by increasing their voter share. The reform of the SNTV system to MMM meant that adopting a single member-plurality voting and proportional representation system has caused dissolving geographical domination, the one-party system to collapse and has increased the likelihood of coalitions. The pursuit of electoral reform by smaller parties and the LDP was based on rational choice incentives. Despite the reform, the LDP is still the dominant party within Japan, using the Komeito party to its advantage and corruption is still prevalent. Although the political system enables similarity there are instances of nuance. Explicit areas of difference in Japanese politics include Article 9 of the Japanese Constitution, Japanese security policy in general and to a lesser extent, US military bases in Okinawa. In the immediate decades following the Second World War, the US-Japan Security Treaty was a source of great controversy, today however, it’s impact on electoral politics is much more muted, with a general consensus in support of the treaty. Nonetheless, these areas of difference such as the Article 9 and specific issues with the US-Japan Security Treaty have existed for a prolonged period and rational choice theory is not the most useful to understand this debate here. Thus, the deployment of structural realism within this essay has helped to understand Japan’s military role which can cause difference. The UK as a case study depicts the divergence that is present within the British political system in comparison to Japan. Party similarity and its effect on the Japanese voter needs increased research and scholarship paid to it, significantly concerning voter apathy, loyalty confidence and swing voters. As a result of the lack of academic work regarding voter behavior here, it is unclear what the long-term implications will be because of party similarity and what this may mean for the Japanese political system.
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NIRA総合研究開発機構 インターン生（英・Loughborough University）