1. Introduction

Since the establishment of the European Union (EU), a considerable amount of  research and literature has been devoted to explaining the European integration and disintegration processes. The integration theories have optimistically focused on the integrating process. These theories have mainly seen the glass half full and have paid less attention to situations in which convergence has been obstructed. Nevertheless, this trend has recently come to a severe halt. The various internal crises within the EU, combined with the recent discourse on Brexit and its repercussions, have initiated a rapid rise in studies on disintegration.

Britons’ decision to leave the European Union in June 2016 has been the dominant reality in the European disintegration. Given the weight and importance of Britain in Europe, Brexit will have profound consequences for the EU as well as the entire continent. Political scholars who have examined the intricacies of Brexit have largely investigated the imminent security or economic measures due to Brexit.

This paper first explores these influential theories in explaining the European Union's disintegration process through the lens of neorealism and constructivism theories. The phenomenon of Brexit will then be investigated and analyzed in more detail through the framework of  the English School. By applying English School’s concepts and assumptions, this study attempts to address the Brexit phenomenon more theoretically. The school is now recognized as one of the major theoretical traditions of International Relations (IR), and in the meantime, it is the only school that is entirely related to the British tradition. Although many of its advocates and theorists have been neither British nor live in the UK, the English School reflects British culture and rationality in many ways, which explains the reasons for which it is remarkable to examine an English phenomenon (Brexit) through this English-based approach.

The study is organized as follows. In the first section, we briefly introduce neorealism and constructivism and juxtapose them with Brexit and the European disintegration. We then characterize the shortcomings of the two mentioned theories in explaining Brexit. In the third section, we will introduce the English school of international relations and its central assumptions, and in the fourth section, Brexit will be explained within the framework of the English school. In the subsections, we apply the Brexit phenomenon in the school's four main assumptions, namely institutions, great power status, pluralist-solidarist debate, and the balance of power. Based on this analysis, we attempt to demonstrate that the English school’s main assumptions can explain the various aspects of the selection phenomenon.

2. Brexit: Theories in Practice

International relations and political science have offered a wealth of theories about integration and disintegration. In this section, after a brief review of two major theories explaining the reasons for the establishment of an integrated union like the European Union, we briefly study  two other theories, which, based on their assumptions, attempt to explain Brexit as a disintegration phenomenon. Finally, we will thoroughly analyze the reasons for Brexit from the perspective of the English School of international relations.

For many years, European integration seemed irrevocable, and the theories of integration inclined to confirm this status. Notwithstanding this confidence, recent changes in the EU and its surroundings generated theoretical debates on the possibility of European disintegration. Following neofunctionalism, European integration goes forward due to the  positive spillovers that it generates (Haas, 1958, p. 292). The limitations of the above theories have recently led to post-functionalism (Hooghe & Marks, 2008, p. 23), a new approach, which emphasizes the influence of domestic and national politics on identities and territorial groups and communities whose interests matter considerably. In this context, the debate about the role and shape of the EU has moved from international levels to national politics and, therefore, to internal political struggles, public opinions, home sentiments, and the masses (Czech & Krakowiak-Drzewiecka, 2019, p. 592). In internal politics, people as voters are more afraid and worried about their gains and losses in migrations, welfare, competitiveness, identity, etc. These feelings have recently been further exploited by political parties, especially the national ones.

Consequently, the key actors of the European drama are not only the governments, bureaucrats, important businesses, and officials, but also the political parties and of course, the citizens. In this respect, we witness the ‘constraining dissensus’ instead of the ‘permissive consensus’ that the officials and political elites have previously enjoyed. The new situation produces weighty political restraints on present and further integration (Czech & Krakowiak-Drzewiecka, 2019, p. 592).

The phenomenon of Brexit seems to suggest that the trend of earlier blossoming integration has come to an end; a considerable number of studies have been conducted on disintegration within the last four years. In fact, numerous external and internal crises within the EU, accompanied by Brexit triggered a rapid rise in such studies. This trend in studies can hardly be considered in terms of a modest phenomenon. As a matter of fact, many phenomena—from the emergence of far-right parties, anti-liberal and populist movements to debt and sovereign crises—have increasingly challenged the structure of the European Union; the basic foundations of European integration have therefore been put into question. It also seems that there is significant asymmetry between the procedures of integration and disintegration. Even though integration processes need many years and considerable labor to occur, the disintegration process can happen in much less time.

After analyzing the existing theories on the logic of European integration, we have selected two theoretical approaches as a starting point in explaining Brexit as a disintegration phenomenon: neorealism and constructivism. Following the analysis of Brexit through these two theories, we will comprehensively examine the reasons for this English phenomenon according to the English School's assumptions of international relations.

2. 1. Neorealism and Brexit

Neorealism's assumptions are generally as follow: the international system is anarchic, there is no credible power above the states, and states cannot be certain of other states' intentions (Lundborg, 2018, p. 230). At least some states have offensive capabilities. At the first glance and according to these assumptions, it seems that this theory leaves no room for integration. Still, this theory has essential views on integration, especially in criticism of neofunctionalism.

Neorealist theorists consider international institutions, such as the European Union, in the context of distribution of material power in the international system. Kenneth Waltz, the most important neorealist, attributes the expansion of European integration to the emergence of the United States after World War II and Western Europe partners' security. Similarly, John Mearsheimer predicts that the collapse of the Soviet Union and the return of a multipolar international system will reduce security concerns and diminish European integration's comparative advantage (Mearsheimer, 1990, p. 24).

The inaccuracy of John Mearsheimer's predictions and the continued expansion of European integration in the 1990s led neorealists to look deeper into the issue of European integration. Neorealists such as Mosser focused on the vital role of small states in the process of integration. Mosser believed that small states could participate in the formation and reform of international institutions so that large states could adhere to institutional rules and norms in order to restrict them from using material power (Mosser, 2001, p. 77).

Although the neorealist theory examines the integration and alliances, it cannot be considered an integration-oriented approach because ontologically, the foundations of neorealism lie on international relations, which are based on power, survival, and self-help analysis. Accordingly, Brexit reflects the neorealist assumption that nationalist sovereignty and policies are still important. Consequently, if we examine Brexit and the current state of European integration from the perspective of neorealism, we must look for independent variables at the macro-level of international politics and consider the whole of European integration as a dependent variable. Therefore, as a European crisis, Brexit can be caused by a change in the balance of power in world politics in favor of other regions such as the United States and Asia, at the European Union's detriment. Perhaps China's emergence as a world economic power and its interactions with the UK and the European Union can be considered influential in this phenomenon.

2. 2. Constructivism and Brexit

Constructivists focus on the conventions, rules, and norms that form international politics; they believe that essential aspects of international relations are socially and historically constructed (Jackson & Nexon, 2002, p. 81). In the Constructivist framework, institutions have a fundamental role and determine actors' identity, motivation, and priorities. Contrary to neorealists, constructivists believe that material capabilities do not matter as much as how people understand their place in the world. Accordingly, constructivists emphasize the formation of identities and their role in foreign policymaking.

In European studies, scholars such as Wendt believe that EU institutions shape their behavior, individual priorities, and identities. This process can generate cooperative behavior, even in an exogenous self-help system (Wendt, 1992, p. 392). These scholars believe that the integration process has had a significant impact on European states' systems and units' construction and has changed their identities and interests. As seen, the constructivist approach is ontologically more flexible than rationalist approaches, since it can provide a reasonable basis for understanding social ontology, community identity, and shared goals. Constructivists also pay attention to the interrelationships between the domestic and international arenas. On the one hand, they examine the consequences of states' social interaction in the international system and the impact of national norms on international politics. On the other hand, they explore the impact of European norms on states' domestic policy changes (Christiansen, Jørgensen & Wiener, 2001, p. 7)

Concerning Brexit and the current situation of the EU, the constructivist approach can be used to examine issues such as the European identity and the perception of the members of this concept. In times of crisis, it seems that the European identity is negatively affected by certain states and people. In this respect, certain countries are skeptical and seek to regain their national identity. This issue is mostly seen in the people's reaction to the EU institutions' performance through street demonstrations and referendums. In other words, it can be said that the balance between national and transnational identity in the European Union is changing, and the role of transnational identity is shifting towards national identities. As a result, there has been a shift in the priority of interests; countries such as the United Kingdom and Portugal have come under pressure from domestic public opinion to shift national interests over transnational interests.

On the other hand, recent developments have changed the members’ perception of each other within this international institution's framework. As the crisis intensifies, dissatisfaction among members becomes apparent, and members’ singularities and differences are better manifested. These policies exacerbate pre-existing structural problems and nurture disintegrative tendencies (Becker & Jäger, 2011, p. 16).

According to constructivism, identities have both unifying and dividing powers, since they are socially constructed through historical, political, and cultural circumstances and are influenced by their interaction with other actors (Albinger, 2020, p. 3). Due to Britain’s unique historical situation, being an Empire and the leading country of the Commonwealth after World War II, Britain had stronger ties with countries outside of Europe, thus a strong European integration and interdependence were not perceived as Britain’s national interest. In other words, they feared that by accepting a commitment to supranational cooperation with Europe, they would lose independence from the US and subsequently their status and influence with them, while at the same time weakening their links to the Commonwealth (Nielsen, 2019, p. 3). 

In the context of Brexit, the British national interests or the EU shape by whom they think they are and what role they should follow in the globe. According to constructivism, understanding a phenomenon like Brexit will explain how the United Kingdom and the European Union construct their identities. In this regard, ideas of parliamentary sovereignty and the their country’s self-image as a great power can explain the UK’s approach. Simultaneously, the Union’s tendency and commitment to a closer union can explain the EU’s approach.

Although both neorealism and constructivism can raise important issues about Brexit and the European Union's current state, there are shortcomings in these two theories. Neorealism relies heavily on macro-analysis and material factors. On the other hand, although constructivism tries to account for essential factors from the domestic or second level of analysis (Sterling-Folker, 2002, p. 21), most constructivism issues are subjective and far from objective facts. In this respect, it seems the English School can modify the neorealist macro-level analysis and present a more nuanced view of the role of the underlying elements in the emergence of Brexit, compared to constructivism, which can lead to a deeper understanding of Brexits and the European disintegration. The English School of international relations is one of the most traditional school of thought, and almost the only one that has been fully developed in England (Dunne, 2011, p. 1). At the first stages, the school was not concerned with regional cooperation, but in the evolution of this meta-theory, European integration has been increasingly applied. It should be noted that this paper does not seek to state that Brexit can only be explored in the context of a particular theory. It emphasizes that in the context of the English School's main assumptions, the phenomenon of Brexit can be studied and analyzed in more depth and clarity.

3. The English School of IR; an Overview

The English School of international relations (also called liberal realism, the International Society school, or the British institutionalists) is considered as an essential rival to the American mainstream. The English School (ES) offers a version of international relations that merges morality and power, agency and structure, and theory and history. One noticeable consequence of this theoretical ambition is that the English School's boundaries often appear indistinguishable, explaining the continuing debate about who belongs to the English School and how the ES differs from other theoretical approaches of world politics (Dunne, 2011, p. 3). Robert Jackson defines the English School as follows:

There is no conceptual agreement here, no single paradigm with its discourse. What one finds is less reassuring but also more interesting: a colloquy of different academic voices, each one attempting to fasten the reader's attention on recommended ways of understanding and responding to normative issues that arise in the course of international relations. Indeed, each attempting to define them in the first place. Thus, to read these volumes is to encounter neither a Discourse nor a Babel but instead a variety of theoretical inquiries which conceive of international relations as a world not merely of power or prudence or wealth or capability or domination but also one of recognition, association, membership, equality, equity, legitimate interests, rights, reciprocity, customs and conventions, agreements and disagreements, disputes, offenses, injuries, damages, reparations, and the rest: the normative vocabulary of human conduct. (Jackson, 1992, p. 271)

The English School is a theory of international relations that originated from the departments of international relations at the University of Cambridge and Oxford University, and has increasingly moved beyond the UK. The evolution of this school has had four distinct stages: the first stage was related to the formal structure of the international system, in particular the principle of sovereignty, the role of international law, the balance of power, and the role of the great powers, and was mostly attributed to scholars such as Hadley Bull, Herbert Butterfield, and Martin White. At this stage, the school's central concept, the international community, was founded, whose main concern was establishing and continuing the international order by the Cold War's impact. Accordingly, the major powers were the most important actors in the system, with little attention given to small states (especially states known as the Global South) and non-state actors. In fact, the school's emphasis on state priority, the role of the great powers, and the balance of power have led certain scholars to argue that the ES is not a distinct school of thought, but rather a form of political realism (Wilson & Oliver, 2019, p. 1010).

The second stage is related to the international community's expansion and its geographical spread from Europe to the whole world. At this stage, concerns and attention to international order have been replaced by the nature of the process. Scholars such as Buzan have challenged Europeans' monopoly and superiority and the linearity of Bull and Watson's conceptions (Bull & Watson, 1984, p. 204).

Since the 1980s, the English School has also added human rights and international community goals to the above-mentioned principles. In this sense, order was still a significant concern, but the duality of order and justice was questioned and challenged. More positive ethical conceptions of pluralism have been created, which drew the school's focus from the acceptance of cultural, moral, and political heterogeneity to the recognition of the critical role played by international rules and norms in maintaining diversity (Buzan, 2014, p. 16).

The final stage of ES development is related to the institutional foundations of international society. Based on the writings of classical ES scholars, such as Wight and Bull, contemporary ES scholars engage in theoretical and empirical work on the identity, function, and importance of the fundamental institutions of the international society, including their role as creators of change (Holsti, 2004, p. 26-27). The new classification of institutions has expanded their role in linking regional communities and their constructive relationship with international organizations such as the European Union and the United Nations. The fourth stage of the English School development seems to be the most productive throughout the theory’s elaboration and perfection.

4. The English School and Brexit

In its early stages, the English School has been less concerned with regional integration; creating a new multinational institution such as the European Union has therefore weakened the school's notion of sovereignty as constitutional independence. However, today, with the emergence of Buzan's views, the regional international community has become one of the most important subdivisions in the school discourse. The EU is not solely an international organization; it is a post-Westphalian entity, precisely what weakens the EU. The constant expansion or contraction of the Union can have consequences for the international community. A part of the Union's weakness dates back to its failure to develop the Union's defensive capability and identity (Bull, 1982, p. 162). Even if we consider such a capability and identity for the Union, the departure of one or two member states with significant military power will have significant consequences for both the Union and international security.

Many opponents of Brexit believe that leaving the Union will have serious economic consequences. They argue that the EU is globally recognized as the largest free-market, and the UK's financial balance with the Union is very high. In response, it should be noted that this paper's focus is on the British school's view of Brexit, and in this regard, the school has simply ignored the economy. In other words, for the school, the economic dimension of international relations has always been on the periphery and has not been seriously analyzed even by phenomena such as interdependence and globalization (Wilson & Oliver, 2019, p. 1013). Furthermore, concerning the British economic problems, if the UK leaves the EU, the Union will also suffer from economic crises because it will lose one of its oldest, largest, and wealthiest members, which can lead to the normalization of other countries' withdrawal from the Union, and become a domino for other countries to leave the Union. We should also note that Britain has never been fully committed to the EU economic projects. Put differently, the UK has always been half outside and half inside the European Union.

As mentioned above, within the English School framework, the paper analyzes the UK's withdrawal from the European Union in four assumptions: institutions, the UK's status as a great power, pluralist-solidarist debate, and balance of power. While this paper briefly deals with these assumptions, it must be noted that the English School has provided a rich history of debate and analysis for each of them.

4. 1. Institutions

By recasting the English School principles, Barry Buzan distinguishes two types of institutions: (a) Primary institutions which are formed throughout history and are normative structures. Primary institutions are of interest to the English School scholars; Nicholas Onuf calls these institutions evolved institutions. (b) Secondary institutions are designed as regimes or instrumental organizations that have been  consciously designed by states. These human-made organizations mainly focus on regime theorists and neoliberal institutionalists; Onuf calls them designed institutions (Buzan, 2004, p. 120).

According to the ES, primary institutions are long-term practices among states (such as diplomacy, law, and war) rather than international bureaucratic structures (secondary institutions) that may be established to facilitate state interaction. In this respect, the European Union can be considered as an evolving organization. Although it has not been successfully reproduced in other parts of the world, the EU has had a significant impact on international society institutions. In this regard, certain scholars may argue that (for specific reasons such as trade, euro management, environment) the formation of the European Union, has negatively affected the concepts of sovereignty, land, and nationalism . In other words, through the EU, trade and financial liberalization have strengthened, but boundaries (i.e., the social, economic, and political importance of borders) have weakened. In this regard, Holsti argues that the primary sovereign and territorial institutions in integrating states into the EU have been weakened; He gives a more realistic picture using a six-category classification of institutional change (Holsti, 2004, p. 58).

According to Holsti, institutional change can be seen from the following perspectives: emergence, obsolescence, degree of complexity, etc. For example, in the modern international community, business is a new entity, and colonization is obsolete. In these circumstances, the EU has added complexity to sovereignty (Holsti, 2004: 209). These complexities have been added by clarifying EU law as superior to domestic law, compulsory directions, establishing a system with a qualified majority vote without considering countries' importance. Simultaneously, the symbols and rituals of national sovereignty have been ignored, and the European Parliament's performance as a superior body has led to the isolation of national assemblies. In this respect, utilizing many European Union channels, diplomacy has also lost its usual flexibility and has become more complicated than before.

The fact is that Brexit is the most explicit symbol of the reassertion of sovereignty in the European Union and the most significant challenge to the retreat of nationalism. Brexit may also create a new life in the institution of the balance of power; for the first time in half a century, a large Western European country will be outside the area of merged sovereignties. Article 50 of the Treaty on European Union states: “Any Member State may withdraw from the European Union under its constitutional requirements” (Cîrlig, 2020, p. 5). In this regard, Robert Jackson makes a fascinating quote about British sovereignty when he says:

Sovereignty is like Lego: it is a relatively simple idea, but one can build almost anything with it, large or small, as long as he follows the rules. The British (English) used sovereignty to separate themselves from the medieval Catholic world (Latin Christendom). Then they used it to build an empire that encircled the globe. Later, they used it to decolonize and thereby created a multitude of new states in Asia, Africa, and elsewhere. Then they used it to enter the European Union. It has other uses besides these (Jackson, 2005, p. 74).

Indeed, the Britons made other uses. They used sovereignty to leave the EU.

4. 2. The Great Power Status

According to the English school, the great powers' contribution to international order derives from inequality between the states that shape the international system. The school's attention to the great powers is such that it considers it, along with the balance of power, law and diplomacy, and war, as one of the four main factors in forming modern international societies. Because states are completely unequal in power, the great powers are recognized to be the only states pertinent to the issue (Bull, 1977, p. 200). Due to their supremacy, the great powers are considered as major actors which playan important role in promoting international order by pursuing effective policies. An excellent example of this supremacy is the United Kingdom's position in which Britain enjoys leadership among the Commonwealth states (Bull, 1977, p. 208).

Many people in Britain hold that their country is a great power on the world stage. This is primarily due to a shared view of Britain's glorious' past.  Great Britain stood in the vanguard of the significant surges of European expansion that shaped the world between the 17^th and 19^th century: commerce and conquest in the 18th century, industry and Empire in the 19th. All these movements were intertwined with the lucrative Atlantic slave trade, and the profits from that trade lubricated Britain’s commercial and industrial revolutions (Reynolds, 2019). Therefore, for the Britons and their Empire on which the sun never set, Great Britain's name is associated with the 'great' power; membership in the European Union has therefore degraded this position to be a normal state. In this regard, Christian Lequesne argues that the British Conservative establishment has trouble admitting that Great Britain has become a middle-range power on a global scale. Conservatives are tense on glorious symbols of the past (the invention of parliamentarism, the Empire), and they consider with suspicion anything that could endanger the UK’s image of greatness. He believes that their vision of Great Britain is entirely ideological and they are convinced that their nation can face the world alone. In this connection, Hadley Bull argues that most ordinary British people have a hostile attitude towards European membership (Bull, 1982, p. 161).

In addition to the British public mindset, the notion of being a great power is also quite prevalent in the official circles of the United Kingdom, and has become an influential factor in determining British foreign policy (Morris, 2011, p. 326). In this respect, the British military and economic power are fully promoting this mentality. Britain is one of the world's nuclear powers, and it is also one of the five permanent members of the Security Council. To scrutinize this from a theoretical point of view, it is necessary to mention that power's objective features are the central theme of political realism. In other words, the power of a state is measured and evaluated by its objective capabilities. Thus, Britain is a great power in terms of realism and the beliefs of scholars like Mearsheimer. In this regard, the English School, which borrows from realism, emphasizes the great powers' role as the international arena's main actors. Hadley Bull emphasizes the role of the great powers in the international system to the extent that it gives them the responsibility of the international order and security (Bellamy, 2009, p. 147). Accordingly, a great power will ultimately not be able to share its foreign and defense policies with smaller and less important countries because its capacities would be capable of pursuing its interests alone.

As mentioned, the objective sources of a country's power are vital for its recognition as a great power, such as the armed forces, population, industrial production, and technological capabilities; the English School adds society to these sources. This is precisely the situation of Britain as a great power. Among Britons, society and historical strength, alongside material sources, are the main factors in describing the country as a great power that can pursue its own interests alone, resulting in a rather pessimistic perception of integration  with other countries (Morris, 2011, p. 340).

In this regard, we can compare the European Union and the United Nations, two prominent secondary institutions for the United Kingdom. Perhaps one of the most important differences between the EU and the UN is the over-equality in the European Union. In the United Nations, in addition to being a member of the General Assembly, five great powers have the veto right and are granted a permanent seat on the UN Security Council; perhaps if they did not have such privilege, certain states would withdraw from the UN. Meanwhile, the European Union decision-making policy is based on one-member-one-vote, which may not satisfy the great powers.

According to this English School analysis, the advocates of Brexit, both in independence in foreign policy decisions and economy, predict a bright future free of bureaucratic restrictions and costs of being a member of the European Union.  For them, Brexit will have significant achievements in making Britain feel great again if politicians pay attention to the vote's reasons in 2016. Consequently, Britain's growing convergence in the European Union has increasingly challenged the role of this country as a world power, and this issue, based on the above-mentioned English school’s assumptions, has provoked opposition from a significant section of the British public and elite in the face of further integration with the European Union.

4. 3. Pluralist-Solidarist Debate

A key debate within the English School revolves around pluralism and solidarism. Pluralism refers to international societies with a relatively low degree of shared norms, rules, and institutions, while solidarism refers to a relatively high degree of shared norms, rules, and institutions. The pluralist-solidarist debate is basically about how an international society relates to the world society or people. A pluralist interpretation would state that despite the EU’s membership criteria (i.e., economic, political, and cultural conditions), each country has a ruler and is responsible for its own territory and people. A solidarist viewpoint would stress that the European Union has the authority to impose its power on other member states, and turn all the states into a uniform state and even intervene in domestic affairs (Stivachtis, 2018, p. 3).

In this respect, the classic view of Hedley Bull was that the idea of an international society is pluralistic principle. For Bull, the United Nations (UN), and its network of laws and institutions, should not be interpreted as an essential revolutionary change. Instead, it represents a change in the appearance of international politics, which explains Bull's skeptical view of the United Nations. Nevertheless, what is the difference between the UN and the EU? There is no doubt that the United Nations is a solidarist institution for ES scholars, but within the UN's instructions, there is still a combination of state-centric solidarity and cosmopolitan solidarity (Buzan, 2014, p. 115).

Unlike the UN, Buzan claims that the EU is a regional society in flux with thicker society elements developed through cultural, political, and economic interactions. In Buzan’s view, the EU society can be considered as a much more solidaristic society than the UN because its focus on the society is not only on coexistence and competition, but also on cooperation in the pursuit of joint gains and the realization of shared values. Therefore, common states’ EU membership (not exceptional ones) requires them  to be identified with and adhere to  the EU’s common interests and values, and accept the EU’s rules and institutions (Seagle, 2014, p. 69). In this sense, belonging to a society has the potential to distinguish between solidarism and pluralism. As mentioned, pluralism is about national interest separation and simple coexistence between the periphery and core, while solidarity is about unity in observing common values and purposes (Seagle, 2014, p. 69). Brexit can be seen as a reaction to the growing solidarism of the EU. This reaction, triggered by Britons, expresses that a broader and shallower Europe is better than a deeper Europe. However, in the eyes of many British observers, Europe, like the past, will stand against this view, and will become both wider and deeper every passing day. The Britons believe that this will have profound negative consequences on their national sovereignty.

4. 4. Balance of power

The balance of power is one of the essential pillars of realism. Alongside realism, there is a relevant perspective among scholars about the English School, who argue that the balance of power is an international society institution, which binds states tighter together.

Bull argues that the balance of power is an essential condition of international law and that the actions required to preserve the balance often involve violation of international law. Hedley Bull argues that one function of the balance of power has been to foster an international society resting on shared understandings among states (Little, 2007). The English School discusses the earlier historical theorists' emphasis on the balance as part of a European community and social order, rather than an exclusive focus on raw power‐politics and national competition. Many of the school’s scholars,  such as Richard Little, adopt a historical perspective on the balance of power, arguing that it is analytically useful to explain international stability and community. Little investigates the balance of power as a model from an English School perspective (Andersen, 2016, p. 9). In this respect, the United Kingdom is closer to the United States in terms of historical alliance and shared understanding, compared to other European countries such as France and Germany, while the European Union is moving closer to deeper integration of its members through shared racial, linguistic, and cultural factors.

In general, the Anglo-American special relationship is one of the most important factors preventing the UK from integration in the European Union. In this regard, the UK-US cooperation level in trade, military planning and operations, nuclear weapons technology, and intelligence is described as unparalleled, compared to the major European powers. Close relationships between British and American heads of government, such as Ronald Reagan and Margaret Thatcher, or Tony Blair and both Bill Clinton and George W. Bush, have been widely observed in the past. In such circumstances, for the United Kingdom, the choice between the European Union and the United States will not be a difficult one (Hewitt, 2018).

5. Conclusion

This paper adopts a theoretical framework for the explanation of Brexit as a profound political phenomenon. Even though specifying a limited and straightforward classification of disintegration theories for explaining Brexit is highly problematic, we have attempted to investigate the way in which major theories are related to and explain the Brexit phenomenon. In this regard, we have characterized neorealism and constructivism as the two influential disintegration theories. Neorealism, emphasizes the anarchic nature of the international system, and holds that any crisis in each member can quickly lead to the separation of the member or even the union's dissolution. In this regard, Brexit can be caused by a change in the balance of power.

On the other hand, constructivism holds that identities are socially constructed through historical, political, and cultural circumstances influenced by interaction with other actors; identities have a unifying and a dividing power. According to Britain’s unique historical identity, being an Empire and the Commonwealth leader, Britain has stronger ties with countries outside of Europe, than those within the continent. Accordingly, Britain fears that by accepting a commitment to supranational cooperation with Europe, it will lose its independence as well as its influence in other parts of the world.

As discussed in the second section, although both neorealism and constructivism have raised essential issues in explaining Brexit, there are still shortcomings according to their reductionist approaches. Neorealism relies heavily on macro-analysis and material factors. On the other hand, although constructivism tries to account for essential factors from the domestic or second-level of analysis (Sterling-Folker, 2002, p. 21), most constructivism issues are too subjective and far from objective facts. That is the reason for which these two theories may not seem to be able to effectively explain Brexit.

Contrary to the above-mentioned theories, the English School of international relations as a meta-theory, which has the ability to explain different political phenomena, may be effectively applied to analyze Britain's withdrawal from the European Union (Brexit). By employing the English school as a distinct approach for explaining the rationale of Brexit, this study  has attempted to provide a satisfactory image of the Brexit phenomenon. In this respect, we have applied the English School's main assumptions in international relations to the United Kingdom's current conditions to better analyze and explain the phenomenon.

In this respect, by demonstrating the ongoing tensions between the Uk’s institutionalized state-centered sovereignty and the European Union's cosmopolitanism, we attempted to address the reasons for Britain's intolerance to abide by the rules of such an institution through the principles of the English School. In this regard, the English School argues that secondary institutions (such as the European Union), along with their positive factors, weaken the primary institutions of sovereignty and nationalism, and this, more than other factors, pushes the great powers under pressure. This happens when the more powerful countries in a union have the same duties and rights as the 'ordinary' ones. Therefore, if the Union cannot satisfy an 'exceptional' country, it should expect future irreconcilability. In this context, if an institution does not undermine the sovereignty, identity, and independence of that 'exceptional' country and does not make an attempt to satisfy the country by granting privileges, it can still have it as a member, as long as the UN and NATO are institutions that Britain does not intend to leave.

Another reason for the Brexit phenomenon is that the UK has historically been one of the world's major decision-makers and has adopted its own policy based on its national interests. In the minds of the British people, there is still a tendency to be an exception and superpower; as a result, integration into an institution that puts this country on the same level with many small countries is unacceptable. Given Hadley Bull's view of the pluralistic international society, deep integration into the EU for a country with many capacities seems  irrational. In Hadley Bull's opinion, the characteristic of pluralism over deep solidarity provides a better understanding of international society's status. In this respect, by comparing the United Nations as an institution that gives its members more independence and the European Union, which is an institution that seeks to deepen the integration of its members' sovereignty into the Union, we can see the reasons for which even hostile superpowers have succeeded in coping with each other and preserving the United Nations after decades.

When the English School of international relations speaks of power balance, its realistic approach is more pronounced. The importance of the balance of power as one of Hadley Bull's five institutions, along with diplomacy, war, international law, and the role of great powers, has expanded to some extent, which plays a privileged role in his Anarchical Society. It helps provide the conditions in which other institutions, on which international order depends, can operate. Bull not only identifies the balance of power as one of five key institutions, but also argues that it underpins the other four institutions. Bull also describes the balance of power as an essential institution for maintaining international law and preventing conflict. Concerning Brexit, we should note that Bull placed considerable responsibility for international security and international affairs management upon the great powers' shoulders (Bellamy, 2009, p. 147). In this regard, the European Union is a potential superpower, in contrast with the United States, and it is also making its way into a more comprehensive, yet more profound, institution by which it will become an actual superpower against the UK’s special ally (the United States) shortly. In such conditions, a full-fledged balance of power will form and, given the many Anglo-American commonalities, it is not difficult to understand Britain's choice.

In conclusion, by studying the English School’s main assumptions outlined in this paper, the reasons for the Brexit phenomenon are not far-fetched. It seems that there is no integration for the United Kingdom from the English School’s perspective. Inspired by this theory, we have claimed that Brexit, explained within a suitable theoretical classification, can be considered as a determinate and predictable phenomenon, which exemplifies a rationally motivated act of withdrawing from the European Union.