1.1 The New Complexities of EU–Turkey Relations

More than 60 years after Turkey’s application for association with the European Economic Community (EEC), relations between the European Union (EU)Footnote 1 and Turkey exhibit many unique features driven by persistent ambivalences, intricacies, and growing interdependencies across a wide array of issue areas. A tortuous, multifaceted love–hate relationship between the EU and its oldest associate member has subsequently emerged—a ‘curious love affair’ (Aydın-Düzgit & Tocci, 2015: 1). Starting from a broad definition of EU–Turkey relations as ‘the totality of interactions within the international system’ (Buzan, 2009), the relationship extends not only to the disciplines of political science, economics, and history but also to legal and sociological aspects. The multiple layers of relations produce—and are subject to—a dense net of interdependencies,Footnote 2 which make issue-specific cooperation and policy harmonization a necessity (Moravcsik, 1997). The mutual policy sensitivity between the EU and Turkey engenders costs and benefits for both sides across a broad spectrum of areas including foreign and security policy, trade, migration, energy, and the environment. Beyond that, EU–Turkey relations impact the wider neighborhood and the global arena, be it the conflicts in the Middle East and North Africa (MENA) region, the transatlantic security agenda, or the implementation of the United Nations (UN) 2030 Agenda for Sustainable Development . Building on their respective capacities, Turkey, an ‘emerging middle power’ (Öniş & Kutlay, 2017: 170), and the EU share the aspiration to shape regional and international developments and bodies alike. In this, EU–Turkey relations have facilitated cooperation among a broad set of actors, including state and non-state actors, which operate in a complex multi-level setup and within multilateral frameworks like the North Atlantic Treaty Organization (NATO) or the Group of 20 (G20).

The strategic importance of EU–Turkey relations in (geo-)political, economic, and societal terms does not exhibit a clear, linear developmental path. Over many decades, the relationship has not only been a complex one but has also featured many stop-and-go cycles. There have been phases of rapprochement and progression, but also periods of indifference or regression—sometimes dominated by dynamic changes, sometimes by slow-moving developments or stagnation. Moments of EU–Turkey cooperation have thus been followed by periods when the actors drifted apart in non-concerted action—before new developments reminded them of the need to jointly manage their interdependence and, eventually, of their commonalities.

Today, the ebbs and flows in EU–Turkey affairs (Narbone & Tocci, 2007) have started to stagnate and cede their place to a ‘seemingly divergent relationship’ (Müftüler-Baç, 2016: 17) that lacks a sense of basic mutual trust and reliability between these ‘key strategic partners’ (Delegation of the EU to Turkey, 2020). While phases of estrangement have started to last longer, periods of consistent collaboration without major disruptions have practically disappeared (see also Reiners & Turhan, Chapter 16). Turkey is increasingly perceived by the EU and its member states as an ‘unpredictable and unreliable partner’ and as a conflict-inducing ‘hostile neighbor’ (Arısan-Eralp, 2019: 3) that is gradually dissociating itself from the Union’s core norms and principles. For Turkey, on the other hand, the EU is progressively regarded as an enervated transformative power due to the resurgence of ‘illiberalism as a driving force across Europe’ (Öniş & Kutlay, 2020: 198) and as an emerging geopolitical rival steering power struggles in Turkey’s neighborhood, including Libya, Syria, and the Eastern Mediterranean.

These new dynamics unfold against the background of the comatose state of Turkey’s accession process, which constituted the institutional substratum of the bilateral dialogue together with the 1963 Association Agreement for many years. Following their commencement in October 2005, Turkey’s EU accession negotiations entered a long-term trance in 2011 with only three negotiation chapters opened since then. The EU–Turkey Statement issued after the joint summit on 18 March 2016 (widely referred to as the EU–Turkey refugee ‘deal’) incentivized Turkey to cooperate on the management of irregular migration flows to Europe through, inter alia, promises to ‘re-energize the accession process’ (European Council, 2016: para. 8). Despite this vow, Turkey’s accession process entered a de jure freeze when the Council concluded in June 2018 that ‘Turkey has been moving further away from the European Union and […] no further chapters can be considered for opening or closing’ (Council of the EU, 2018: para. 35).

These developments have led to the gradual emergence of a paradigm shift in EU–Turkey relations, placing a stronger focus on the possibilities and opportunities of alternative forms of cooperation beyond the accession perspective, which has dominated the debates for decades. At the same time, the failure to agree on the modernization of the EU–Turkey Customs Union (CU) and the suspension of the EU–Turkey high level dialogues on energy and economy in 2019 (Council of the EU, 2018: para. 35; 2019a: para. 4) raise doubts about the prospect of an alternative partnership model based on sector-specific functional cooperation.

The paradoxical coexistence of increasing interdependence and the divergence of normative and material preferences requires a systematic re-assessment of the EU–Turkey relationship. The book at hand aims to grasp this new complexity and ambiguity with a focus on the period after 2009 when the Treaty of Lisbon as the EU’s new constitutional basis entered into force. It aims to view, explore, and decode the evolution of the multifaceted, ever-evolving EU–Turkey relationship through three entry points that offer partly complementary, partly competing visions and explanations of the key drivers, actors, and processes that shape the relationship: (1) Theories and concepts, (2) institutions, and (3) policies. The book is accordingly structured in three main parts in order to unpack the conditions under which EU–Turkey relations have developed from these three analytical and conceptual perspectives. It assesses both cooperative behavior and joint approaches to challenges and solutions as well as the circumstances of those periods when constructive dialogue and integrated action to achieve common goals were not possible.

The investigation of the conditions and drivers that shape EU–Turkey relations takes place on the basis of a set of guiding questions and their synoptic, comparative analysis:

  1. (1)

    How can existing theoretical and conceptual models grasp and explain key turning points, periods, and trends in the evolution of EU–Turkey relations?

  2. (2)

    What roles did the central actors, forums, and institutional frameworks play in EU–Turkey relations, and how did the preferences, functions, and competencies of central EU institutions evolve in this context?

  3. (3)

    How did key policies and issue areas of EU–Turkey relations develop and influence the relationship as a whole?

  4. (4)

    How are the exogenous, endogenous, and bilateral determinants of EU–Turkey relations read through the distinct perspectives of the relevant theories, institutions, and policies?

  5. (5)

    What impact has the EU–Turkey relationship had on the EU and Turkey, respectively?

With the ambition to provide full access to a state-of-the-art understanding of EU–Turkey relations and their evolution over time, the volume at hand combines analyses of institutions, policies, and theoretical and conceptual approaches through a systematic approach. We start from the understanding that the study of these interconnected dimensions as distinct objects of investigation offers comprehensive coverage of the interactions between the EU and Turkey. On this basis, complementary and comparative readings of this evolution become visible. To illustrate, we aim to reveal similarities or differences across the preferences and instruments of key EU institutions in their engagement with Turkey and allow for an assessment of the role of institutional actors. We seek to contrast different periods of EU–Turkey relations to show when and how cooperation has developed, whereas progress might have stagnated in other fields at the same time. We are interested in the influence of European and Turkish actors on each other, be it through accession-related conditionality dynamics or through geostrategic considerations. Beyond that, the objective is to contrast competing theoretical and conceptual explanations for the key developments in EU–Turkey relations, ranging from neoliberal to constructivist approaches. Ultimately, this complementary study is meant to generate a basis for extrapolation with a view to the future trajectory of the relationship. It also provides insight into the EU’s and Turkey’s relations with their neighbors and regional or global powers and sheds light on the conditions for cooperation in international relations more generally.

1.2 Key Determinants and Milestones of EU–Turkey Relations

The identification of milestones and determinants of EU–Turkey relations (see Table 1.1) varies depending on the focus of the analysis. The reading of the evolution of relations from an institutional perspective such as the European Parliament, for instance, does not necessarily highlight the same turning points and key drivers as an analysis of a specific policy field like energy or foreign policy would do. Similarly, a view of relations through alternative forms of partnership between the EU and Turkey implies a time horizon different than that of a study of relations from a historical institutionalist or constructivist angle. Despite the differences, most studies refer to a shared set of interconnected sources of influence, which can be categorized into exogenous, endogenous, and bilateral dimensions. In this context, exogenous determinants include international law and multilateral frameworks as well as moments of external crises and key international developments. In turn, endogenous factors encompass internal developments within the EU and domestic developments inside Turkey. Determinants that are directly tied to the bilateral dialogue primarily refer to Turkey’s EU accession process as well as concern sectoral cooperation beyond the enlargement context.

Table 1.1 Milestones of EU–Turkey relations (1945–2020)
Full size table

1.2.1 Exogenous Determinants: Multilateral Frameworks and External Crises

International law and global or regional multilateral settings are among the fundamental exogenous factors that have shaped EU–Turkey relations. They partly concern the joint membership of the EU or EU member states and Turkey in intergovernmental and multilateral organizations and conventions such as the UN (1945), the Organization for Economic Co-operation and Development (1948), the Council of Europe (1949), NATO (1952), the European Convention on Human Rights (1953/4), and the G20 (1999). Turkey’s membership in these organizations mostly helped the country legitimize its seemingly inherent Western orientation (Müftüler-Baç, 1997; Oğuzlu, 2012) and strategically cooperate with EU member states in all major policy domains in multilateral platforms. Lately, however, Turkey’s commitment to multilateral setups such as NATO has been challenged by alternate orientations that are gaining more independence and salience within Turkey (Eralp, 2019). Turkey’s purchase of Russian S-400 missiles is a case in point.

Beyond the joint engagement in international organizations and multilateral forums, external shocks as well as key international and regional developments have had strong impacts on EU–Turkey relations. In this context, EU–Turkey cooperation and policy coordination have been driven by the need to mitigate crisis-impelled externalities. At the same time, divergences in visions and policy preferences between the EU, its member states, and Ankara have become visible in times of external crisis, too. Important external shocks for the evolution of EU–Turkey relations include changes to the post-Cold War international system that sparked Turkey’s partly assertive, partly multilateral regional activism (Sayari, 2000); the war in Kosovo in 1999 and the terror attacks of 11 September 2001, which reinforced Turkey’s function as a potential regional security-enabler and bridge-builder for the EU (Turhan, 2012); the London and Madrid terrorist attacks in 2003 and 2004 and growing Islamophobia in the EU thenceforward (Müftüler-Baç, 2016); and the 1990–1991 Gulf War and the 2003 Iraq War (Aydın-Düzgit & Tocci, 2015). Ankara’s response to the outbreak of the Arab uprisings in 2011 and the ensuing Syrian civil war largely diverged from its Western allies. However, European and Turkish ambitions to control irregular migration impelled a limited, interest-driven rapprochement between the EU and Turkey in 2015/2016. A particularly complicated case for EU–Turkey relations has been the crises related to Cyprus. Initially, in 1974, after the Greek military coup and Turkey’s subsequent intervention on the island, related developments in Cyprus were treated as a bilateral conflict between Greece and Turkey. However, Greece’s accession to the Union in 1981 turned the EU from an observer into a key actor in the evolution of the dispute. Since then, the Cyprus conflict has become a key impediment to Turkey’s accession process and deepening sectoral cooperation between the EU and Turkey in trade and energy matters.

1.2.2 Endogenous Determinants: Internal EU and Turkish Domestic Developments

EU–Turkey relations have been heavily influenced by developments and adjustments concerning the constitutional and institutional architecture of the EU, the preferences and domestic conditions of EU member states, and Union-wide crises. Constitutionalizing acts that led to several treaty revisions over the years (Treaties of Rome, Maastricht, Amsterdam, Nice, and Lisbon) altered the institutions and processes that generate EU policies vis-à-vis candidate states and key third countries including Turkey. The entry into force of the Lisbon Treaty in 2009 introduced considerable changes to the functions and powers of existing EU institutions—inter alia, the European Council, the European Parliament, and the European Commission (see Peterson & Shackleton, 2012). The provisions of the Lisbon Treaty also brought in the office of the High Representative of the Union for Foreign Affairs and Security Policy in juxtaposition to the establishment of the European External Action Service, which jointly carry out the EU’s Common Foreign and Security Policy (CFSP)—a policy domain of significant relevance for EU–Turkey relations.

In addition to reforms in the political system, the enlargement of the EU has influenced its relationship with Turkey primarily in two aspects. First, each enlargement round has amplified the political and public debates over the so-called ‘enlargement fatigue’ of the EU that underpins ‘a general post-accession reticence within the EU towards further widening in favour of a greater focus on deepening integration across Member States’ (House of Lords, 2013: 43). Turkey’s prolonged EU accession process has thus become less appealing across European political circles. Second, the accession of Greece and Cyprus to the EU in 1981 and 2004, respectively, undermined the bilateral feature of their disputes with Turkey and transformed the disputes into regular items on the EU agenda. Partly connected to these enlargements, EU–Turkey relations have also witnessed the expanding impact of member states’ individual preferences in the last two decades. This influence takes the form of unilateral vetoes on negotiation chapters or on the launch of negotiations on modernizing the EU–Turkey CU. In addition, national preferences of individual member states and EU–Turkey relations have been connected by a wide set of factors that have ranged from public opinion to nationalist and Islamophobic tendencies to divergences over policy design and crises. The EU’s efforts to manage irregular migration based on an externalization strategy amid the failure to reform its own asylum and migration policies and find internal solutions have had profound implications for EU–Turkey relations. The European debt crisis (starting from 2009) and the withdrawal of the United Kingdom (UK) from the EU (2020) are additional examples of the EU’s internal crises that have impacted EU–Turkey relations: for instance, by influencing Turkey’s perception of the EU and the debates about the future design of the bilateral relationship.

Domestic developments and transformations in Turkey have contributed to the definition of the scope, components, and overarching complexity of EU–Turkey relations, too. These internal milestones for Turkey largely relate to influential shifts and continuities in political, economic, and societal dynamics. In this context, Turkey’s party-political landscape, Islamist-secularist struggles, the restructuring of civil–military relations, successive constitutional reforms, as well as their effect on Turkey’s progress toward compliance with EU norms and principles have been of relevance. To illustrate, attempted or executed coup plots against copious Turkish governments have acted as important ‘brakemen’ in EU–Turkey relations. The Turkish military’s fortified influence over domestic politics after the coups in 1971 and 1980 brought about the EU’s temporary suspension of its economic and military assistance to Turkey (Yeşilada, 2002) and delayed Turkey’s application for full membership. On a similar note, intensified tensions and estrangement between Brussels and Ankara emerged over passable actions after the July 2016 coup attempt and were coupled with the EU’s criticism of ‘backsliding’ in various issue areas, including public service, the independence of the judiciary, and the freedom of expression in the post-coup political landscape (European Commission, 2016). Beyond that, the election of the Justice and Development Party (AKP, Adalet ve Kalkınma Partisi) to power in 2002, the 2013 Gezi Park protests, and the 2017 constitutional referendum that led to the replacement of the parliamentary system with an executive presidency are among the domestic developments with clear implications for the EU–Turkey relationship.

1.2.3 Bilateral Determinants: Accession Process and Sectoral Cooperation

A final category of major determinants of EU–Turkey relations covers key events and developments that concern Turkey’s longstanding EU accession process and the sectoral cooperation both within and outside the accession framework. The Association Agreement between the EEC and Turkey in 1963 (Ankara Agreement) envisaged the strengthening of economic and trade relations between both parties. It foresaw the establishment of a CU and the exploration of the possibility of Turkey’s accession to the Community. Whereas Turkey’s initial application for full membership in the EEC in 1987 was not accepted by the Community, the EU–Turkey CU entered into force in 1995. After Turkey’s status as an accession candidate country had been rejected in 1997, it was finally acknowledgement by the Helsinki European Council in 1999. In the following years, the commencement of accession negotiations in October 2005, as well as the selective opening of negotiation chapters, were among the key milestones in the accession-related developments.Footnote 3 The provisions of some of these milestones—for instance, the Ankara Agreement and the CU—initially addressed sectoral cooperation and issue-specific policy alignment between the EU and Turkey that were largely separate from the enlargement context. At the same time, the Turkish side viewed these sectoral initiatives, for the most part, as a leap toward full membership in the EU.

Considering the deadlock in the accession process, on the one hand, and growing issue-specific interdependencies, on the other, the EU and Turkey gravitated more and more toward the establishment of functional institutional mechanisms. In this context, the Readmission Agreement of 2013 in conjunction with the initiation of the Visa Liberalization Dialogue, the EU–Turkey Statement on the management of irregular migration flows to Europe in 2016, EU–Turkey joint summits and leaders’ meetings (since November 2015) as well as sectoral high level dialogues on ‘energy’ (since March 2015), ‘counter terrorism’ (joint consultations since June 2015), ‘political issues’ (since January 2016), ‘economy’ (since April 2016), and ‘transport’ (since November 2017) are included among these additional formats. These functional structures primarily envisage the deepening of interest-driven, sectoral cooperation and policy alignment between the EU and Turkey parallel, or complementary, to Turkey’s stalled accession process. As these initiatives can de facto promote Turkey’s sector-specific alignment with the EU acquis, they can also indirectly support progress in Turkey’s accession process. Beside these mechanisms, the EU–Turkey Association Council (54th meeting in March 2019) and EU–Turkey Joint Parliamentary Committee (78th meeting in December 2018) have been integral bilateral channels.

1.3 A Three-Dimensional Approach to Advance EU–Turkey Studies

This volume is not the first endeavor that explores the multilayered universe of EU–Turkey relations. Previous studies built on comparative conceptualizations of Turkey as a partner for the EU across key policies (Aydın-Düzgit & Tocci, 2015; Linden et al., 2012); its embeddedness in changing global, internal EU, or societal processes (Evin & Denton, 1990; Müftüler-Baç, 1997, 2016; Joseph, 2006); or the key obstacles to Turkey’s full membership in the EU (Nas & Özer, 2017). The existing literature has most prominently dealt with the relationship through the spectacles of EU enlargement. The debate can be traced back to the 1970s (Burrows, 1978) but accelerated after the Helsinki Summit in 1999, when scholars started to rethink both the EU’s enlargement policy (Sjursen, 2002; Schimmelfennig, 2001, 2006; Schimmelfennig & Sedelmeier, 2002) and the relationship between the EU and Turkey in this new context (e.g., Eralp, 2000; Müftüler-Baç, 2000; Müftüler-Baç & McLaren, 2003; Park, 2000; Rumford, 2000; Öniş, 2003; Eder, 2003; Emerson & Tocci, 2004).

Since the official start of the accession negotiations with Turkey in 2005, the literature has demonstrated an intensified interest in the transformation processes inside Turkey that followed the accession negotiations; be it from the perspective of EU conditionality (Schimmelfennig et al., 2003; Tocci, 2007; Saatçioğlu, 2009; Süleymanoğlu-Kürüm, 2019) or from the perspectives of ‘Europeanization’ and ‘de-Europeanization’ (Noutcheva & Aydın-Düzgit, 2012; Börzel & Soyaltın, 2012; Alpan, 2014; Tekin & Güney, 2015; Aydın-Düzgit & Kaliber, 2016; Süleymanoğlu-Kürüm & Cin, 2021). Studies on the ramifications of the EU’s internal dynamics for Turkey’s accession process (Müftüler-Baç, 2008; Müftüler-Baç & Çiçek, 2017; Turhan, 2012, 2016), identity questions (Rumelili, 2008, 2011; Lundgren, 2006; Nas, 2012), and Turkey’s alignment with EU norms in various policy fields, inter alia, economy (Togan & Hoekman, 2005; Uğur, 2006), foreign and security policy (Aydın & Akgül-Açıkmeşe, 2007; Oğuzlu, 2008; Yorulmazlar & Turhan, 2015), and migration policy (Bürgin, 2016; Yıldız, 2016), came into prominence after the accession talks formally took off.

Reflecting on the ‘never-ending story’ of Turkey and the EU (Müftüler-Baç, 1998) and the ‘open-ended’ nature of Turkey’s accession negotiations (Council of the EU, 2005: 5), we can observe, more recently, a gradual re-orientation in EU–Turkey studies beyond the exclusive understanding of EU–Turkey relations as just another case of EU enlargement. An emerging array of studies scrutinizes potentials and challenges of alternative forms of partnership outside the accession context (e.g., Müftüler-Baç, 2017; Turhan, 2017, 2018; Saatçioğlu et al., 2019; Akgül-Açıkmeşe & Şenyuva, 2018). This trend is accompanied by scholarly debates on third countries’ selective alignment with the EU acquis (widely referred to as ‘external differentiated integration’) after the withdrawal of the UK from the EU (Schimmelfennig et al., 2015; Lavenex, 2015; Gstöhl, 2016; Leruth et al., 2019).

The book at hand not only builds on these existing studies but also contributes to the state-of-the-art debate on EU–Turkey relations. The volume has been finalized at a time when the ambivalences in the EU–Turkey relationship have broadened. The book assesses the new complexities that have generated the puzzling presence of both increased sectoral interdependence, on the one hand, and progressively diverging normative and (geo-)strategic preferences, on the other. Both sides have witnessed internal developments that bear great potential to affect the relationship: be it the post-coup political landscape in Turkey with ongoing ‘backsliding’ in terms of the rule of law and fundamental rights (European Commission, 2020) or be it the implications of Brexit for the EU polity and the EU’s relations with third countries accompanied by the rise of Euroskepticism and populism in EU member states. The EU–Turkey relationship is a ‘moving target’ that has undergone a critical transformation in recent years. Since the unfolding of the Syrian refugee crisis in Europe in 2015 and the EU–Turkey Statement in March 2016, the relationship has occupied a prominent space in political, public, and academic debates. Turkey’s accession process to the EU might have come to a formal pause in 2018. However, continuing and (partially) increasing interdependencies across a wide set of policies including migration and asylum, security, transport, economy, and trade make the relationship of critical importance for the future of both sides. The EU and Turkey are facing fundamental and immediate common challenges in the neighborhood. These challenges concern the MENA region, Western Balkans, and the Caucasus, economic recovery from the COVID-19 pandemic, as well as the management of irregular migratory flows. Beyond that, both actors have to respond to universal megatrends ranging from climate change and global power shifts in the international order to the impact of digitalization. Entangled in this challenging setup, however, divergences between the EU and Turkey dominate the field of foreign and security policy orientations. The rise of a crisis in the Eastern Mediterranean is a case in point, where conflicting legal views on gas fields (Aydıntaşbaş et al., 2020) imperil a spillover of hostile relations to other issue areas driven by joint strategic interdependencies.

This book starts from the understanding that these developments necessitate a comprehensive, scholarly re-assessment of the EU–Turkey relationship in order to generate novel reference points for an assessment of the future trajectory of EU–Turkey relations. At the same time, the volume goes beyond a mere update of EU–Turkey relations after critical junctures like the refugee ‘deal’. It is distinct from existing analyses because of its handbook character that is derived from the three-dimensional perspective that brings together the analytical lenses of (1) theories and concepts, (2) institutions, and (3) policies. A particular advantage of this design is the opportunity to combine and contrast different angles of assessment. Following a systematic design, all parts address the guiding questions concerning actors, forums, preferences, competencies, issue areas, impact, explanations, and periods according to their roles and relevance for the respective perspectives. In this way, the distinct strengths of different approaches come together through a multi-angled approach that is particularly suitable to examine EU–Turkey relations as a ‘moving target’.

The first part of the book, ‘Theories and Concepts’, puts together complementary and competing conceptual and theoretical approaches with distinct analytical frameworks to study the overall evolution of EU–Turkey relations. The chapters cover approaches from major theoretical schools that are typically employed or referenced in EU–Turkey studies: neoliberalism/liberal intergovernmentalism (Müftüler-Baç & McLaren, 2003; Turhan, 2012, 2016; Reiners & Tekin, 2020), constructivism (Neumann, 1999; Sjursen, 2002; Aydın-Düzgit, 2012), historical institutionalism (Camyar & Tagma, 2010; Bürgin, 2016; Icoz, 2011), Europeanization (Noutcheva & Aydın-Düzgit, 2012; Börzel & Soyaltın, 2012; Alpan, 2014; Tekin & Güney, 2015; Aydın-Düzgit & Kaliber, 2016; Süleymanoğlu-Kürüm & Cin, 2021), rhetorical entrapment (Schimmelfennig, 2009; Bürgin, 2010; Saatçioğlu, 2012), and differentiated integration (Turhan, 2017, 2018; Müftüler-Baç, 2017; Özer, 2020). All chapters include an assessment of the basic features and core assumptions of the theory or concept under scrutiny, a brief review of the associated core literature and terminology, and the identification of key actors, forums, institutional frameworks, and policies most relevant from the respective perspective. They offer a thorough reading of the evolution and key turning points of EU–Turkey affairs through the corresponding theoretical or conceptual spectacles and assess the strengths and limitations of the respective approach in grasping and explaining EU–Turkey relations.

The second part of the book, ‘Institutions’, investigates the institutional machinery of EU–Turkey relations by analyzing the roles and perspectives of the EU’s key institutions (European Council, European Commission, European Parliament) relevant for agenda-setting, external action, enlargement, crisis management, and for the adoption of the Union’s common norms and values in the context of EU–Turkey relations. The study of these institutions is imperative to get a full picture of the bilateral relationship. Cooperation and competition among them not only shape the Union’s policies; these considerably interdependent, ever-evolving institutions also link the EU to the international community (Peterson & Shackleton, 2012: 8–9). In this vein, the contributions in this part discuss the key documents produced by the institution(s) in dealing with EU–Turkey relations and include a description of the respective institution’s internal structure, including actors, mechanisms, decision-making processes, and (diverging) positions. These chapters thereby contribute to the understanding of the evolution of the institutions’ functions and preferences over time in influencing the bilateral dialogue.

Finally, the purpose of the third part of the book, ‘Policies’, is to offer readings of EU–Turkey relations from the perspective of the issue areas most relevant for the relationship: enlargement policy, trade and macroeconomic policies, foreign and security policy, migration and asylum policies, and energy policy. These policy fields have been repeatedly prioritized in official EU and Turkish documents and statements over the past decade to show the importance of an EU–Turkey partnership (European Commission, 2012; European Council, 2015; Council of the EU, 2019b). The chapters focus on the major dynamics behind the evolution of the respective policy over time and pay particular attention to phases and conditions of policy convergence and divergence. The analyses examine the key documents, speeches, and additional primary sources in order to assess the drivers of change and both mutually beneficial and detrimental initiatives.

1.4 Complementary and Competing Perspectives: Theories, Institutions, and Policies

While the individual chapters of the volume work as stand-alone contributions, they provide both internal references to other chapters of the volume as well as external references suitable for a deepened study of the subject. To help contrast parallels and differences, the chapters work with similar instruments and elements such as references to relevant institutional frameworks, key concepts, and time periods. In regard to the latter, the book covers the full history of more than six decades of EU–Turkey relations: from the early days, marked by Turkey’s first application for associate membership to the EEC in 1959, to developments in 2020. Within this time frame, the edited volume pays particular attention to the period after the Lisbon Treaty entered into force in 2009.

Clearly, there are limits to this study, and the book has to leave aspects of EU–Turkey relations unaddressed. To illustrate, in our analysis of the ‘totality of interaction’, the volume does not offer an explicit focus on transnational or inter-societal relations. In this line, no chapter explicitly explores the impact of individual EU member states on EU–Turkey relations despite the great importance of the role of countries like Germany (Le Gloannec, 2006; Turhan, 2012, 2016, 2019; Reiners & Tekin, 2020), Greece, and Cyprus (Güvenç, 1998; Öniş, 2001; Tsakonas, 2001; Çelik & Rumelili, 2006; Dokos et al., 2018) or of the public opinion in individual member states (Ruiz-Jimenez & Torreblanca, 2007). However, the positions and policies of individual member states are covered throughout the volume, for instance, in the chapters on liberal intergovernmentalism (Tsarouhas, Chapter 2), the European Council (Turhan & Wessels, Chapter 8), foreign policy (Torun, Chapter 13), and energy (Sartori, Chapter 15). In this way, the volume also addresses the repercussions of bilateral relations between Turkey and individual member states on the relations between the EU and Turkey as a whole. The same is true for important subjects like human rights, which are not addressed as individual policy fields in this volume but are integral parts of various contributions, including the chapters on historical institutionalism (Icoz & Martin, Chapter 4), Europeanization (Alpan, Chapter 5), the European Parliament’s role in EU–Turkey relations (Kaeding & Schenuit, Chapter 10), and EU enlargement policy (Lippert, Chapter 11).

The ‘Theories and Concepts’ part of the book opens with the contribution by Dimitris Tsarouhas, who examines EU–Turkey relations from a liberal intergovernmentalist perspective in Chapter 2. He argues that the three-step approach to integration espoused by the theory is key to understanding the development of EU–Turkey relations over time. Concrete steps of integration and cooperation, ranging from the CU to the opening of Turkey’s accession talks and the refugee ‘deal’ serve as examples to demonstrate how a transactional, issue-specific character of EU–Turkey relations has evolved over time and is unlikely to change any time soon. The EU’s prioritization of sector-specific interests and the complexity of bargaining between member states with asymmetric powers and diverging preferences on Turkey’s EU vocation have played a central role in this context.

In Chapter 3, Senem Aydın-Düzgit and Bahar Rumelili offer a critical assessment of constructivist approaches to EU–Turkey relations that pinpoint the impact of norms, values, ideas, identities, and discourse. Departing from a distinction between ‘thin’, ‘liberal’ constructivism, on the one hand, and ‘thick’, ‘critical’ constructivism, on the other, they outline the main tenets of the different variants of constructivism and discuss the key premises in view of EU–Turkey relations. In doing so, the chapter provides an encompassing overview of constructivist studies on EU–Turkey relations over three periods, from 1997 to 2020. The chapter closes with food for thought on the future of the constructivist research agenda.

Gülay Icoz and Natalie Martin examine EU–Turkey relations in Chapter 4 through the lens of historical institutionalism. The authors stress the analytical power and relevance of a theoretical perspective that places significance on temporalities, critical junctures, and path dependencies in explicating why Turkey’s accession process has endured despite the absence of any major progress over the last decade. They argue that individual member states’ and EU institutions’ vetoes on negotiation chapters, the Arab Spring, and the illiberal drift within Turkey have served as critical junctures that have slowed down or sped up Turkey’s accession negotiations at various points in time. Following this assessment, the chapter shows how Turkey’s accession process has endured mainly because of the EU’s security considerations, which have functioned as a counterweight to normative concerns.

In Chapter 5, Başak Alpan presents a reading of the relationship from one of the most prominent conceptual approaches in EU–Turkey studies, the perspective of Europeanization. In her contribution she identifies four phases of convergence and divergence between the EU and Turkey, which are each characterized by a distinct combination of components along the dimensions of polity, policy, and politics. Alpan argues that while the Europeanization process considerably transformed polity, policy, and politics in Turkey until the launch of accession negotiations in 2005, selective Europeanization and de-Europeanization dynamics have been intertwined in all three domains from 2006 onward. A key feature of the study is the analysis of the Turkish domestic debate on ‘Europe’ over time, which shows how the EU has served as a point of reference for Turkey’s reforms and domestic discourse, albeit with different connotations.

Frank Schimmelfennig presents the conceptual approach of rhetorical entrapment in Chapter 6. The approach emphasizes the impact of argumentative commitments on the behavioral preferences of self-interested community actors. He argues that in the context of EU enlargement, existing member states commit themselves to the Union’s accession rules and ethos-based obligations. This ‘entrapment mechanism’ not only functioned as a key driver of the Eastern enlargement but has also shaped Turkey’s accession process, particularly in the run-up to the launch of accession negotiations. At that time, he argues, opponents of Turkey’s membership felt obliged to decide in favor of accession talks against the background of ‘prior argumentative commitments’ and Turkey’s reform endeavors to align with democratic community norms. Beyond that, Schimmelfennig investigates why negotiations started to falter soon after their onset and concludes that Turkey-skeptics were released from the rhetorical trap once Turkey started to deviate from the path toward liberal democracy.

In the final chapter of the first section of the book, Chapter 7, Funda Tekin starts from the conception of Turkey as a unique accession candidate with a dubious accession perspective. On this basis, she examines the relationship with the EU from the perspective of differentiated integration. Tekin argues that the multidimensionality of EU–Turkey relations constitutes a state of conflictual cooperation that demands the consideration of alternative forms of integration outside the accession context in order to preserve and elevate existing forms of association between the two sides. The chapter elaborates on whether prevailing variable geometries in EU–Turkey relations can promote the formulation of a partnership model that would offer a soft landing from the fallout of the accession procedure. By embedding the concept of differentiated integration into the key tenets of the main European integration theories, the contribution also provides a strong cross-connection to other approaches presented in this volume.

Part II of the book views EU–Turkey relations through the perspective of ‘Institutions’. It starts with a contribution by Ebru Turhan and Wolfgang Wessels on the role of the European Council in framing EU–Turkey relations (Chapter 8). Identifying the European Council as the key institution in determining EU–Turkey relations, they highlight its three main functions within the EU system for shaping the relationship: ‘master of enlargement’, ‘external voice and crisis manager’, and ‘agenda and direction setter’. Drawing on this categorization, Turhan and Wessels explore the major turning points, shifts, and continuities in the central functions, internal dynamics, and preferences of the key institution. The findings suggest a growing trend toward a more conflictual and hostile relationship between the European Council and Turkey as well as the expanding ‘bilateralization’ of the relationship. Still, with their central powers and functions, the Heads of State or Government will remain a key driver of the future trajectory of EU-Turkey relations, demonstrating an increased interest in ‘thinking outside of the accession box’.

In Chapter 9, Alexander Bürgin reviews the European Commission’s relations with Turkey across a selected array of policy areas. His analysis illuminates two central aspects of the Commission’s influence: the Commission serves both as a ‘guardian’ of the constitutive rules of the enlargement process and as an ‘agent of change’ in Turkish domestic politics, even in times of severe estrangement and amid bilateral disputes between the EU and Turkey. Bürgin shows how the Commission’s management of the Instrument for Pre-Accession Assistance (IPA) has promoted administrative capacity and policy-learning processes within Turkey’s bureaucracy, which, in turn, has engendered continued selective policy alignment despite the waning relevance of Turkey’s EU accession process. In this context, he characterizes the Commission’s role as an autonomous actor within the EU system and stresses its relevance for a norm-based, unbiased assessment of EU–Turkey relations.

In Chapter 10, Michael Kaeding and Alexander Schenuit examine the formal competencies, key procedures, and internal dynamics of the European Parliament (EP) in shaping EU–Turkey relations. Based on the voting behavior of the members of the EP, they show how the Parliament’s position on Turkey and its relationship with the EU have evolved over time. Following growing support for Turkey’s EU accession from 2005 to 2008, the EP has gradually developed into the only EU institution that openly lacks a political majority for the continuation of Turkey’s accession process. The authors find that the EP has officially closed its ‘accession door’ for Turkey. At the same time, EP resolutions from 2005 to 2019 reveal the increasing relevance of new narratives for cooperation with Turkey that can orient the future trajectory of the EU–Turkey relationship.

Part III of the book deals with key ‘Policies’ in EU–Turkey relations. In Chapter 11, Barbara Lippert explores the relationship through the lens of one of the most influential and studied policy areas, namely the EU’s enlargement policy. Her chapter presents the concepts, motives, and criteria for EU enlargement and applies them to the Turkish case. In this context, she addresses the aspects of Turkey’s potential EU membership that are also of highest relevance for other areas of bilateral interaction, such as the question of Turkey’s ‘Europeanness’, its ‘strategic value’, and the role of ‘political order, democracy, and political culture’. Crucially, the contribution maps how specific features of the EU–Turkey relationship have played out from the period of pre-accession to the present accession negotiations. Lippert concludes that they have made Turkey a unique and (almost) dead case of EU enlargement policy.

In Chapter 12, Mehmet Sait Akman and Semih Emre Çekin examine the macroeconomic and trade policy dimension of EU–Turkey relations. The authors start from the question of to what degree and under what circumstances the EU has functioned as an ‘anchor’ for the Turkish economy. Their analysis reveals that the European anchor facilitated Turkey’s far-reaching macroeconomic and trade policy transformation until 2008. The establishment of the CU was particularly influential in Turkey’s trade policy transformation. At the same time, they argue that a comprehensive study of Turkey’s economic reforms should also take into account the impact of the ‘multilateral track’ under the guidance of the Bretton Woods institutions. The authors conclude that the EU’s role in the economic arena is diminishing and that the ‘anchor’ function might have been lost amid changing political circumstances, at least as long as an upgrade of the CU does not bring new momentum to economic relations.

The compatibility of Turkish and EU foreign policy is the focus of Zerrin Torun’s analysis in Chapter 13. Based on a critical assessment of key international developments and Turkey’s alignment with the EU’s CFSP, she distinguishes four periods from 1959 to 2020 featuring different constellations of convergence and divergence. Turkey’s initial Western orientation after World War II, its increasing aspirations to create a new regional order, its development of ‘soft power’ instruments in the face of external shocks, and its progressively diverging (geo-)strategic interests with the EU in Syria and the Eastern Mediterranean are presented as the most influential drivers in this regard. The chapter concludes that issue-specific future cooperation between both parties based on ad hoc mechanisms might emerge as a counterweight to Turkey’s decreasing convergence with EU foreign policy.

In Chapter 14, Ayhan Kaya investigates Turkey’s migration and asylum policies from the perspective of Europeanization processes. Both before and after the March 2016 EU–Turkey Statement on irregular migration, this policy field constituted one of the most relevant and controversial areas of cooperation. Kaya reveals how Turkey initially aligned and then started to de-align its relevant policies and laws with or from EU norms after the 1999 Helsinki Summit. In this context, he scrutinizes the impact of key international developments, historical roots, Turkey’s EU accession process, and recent crisis situations in the Middle East on Turkey’s asylum and migration policies. Kaya shows how the Europeanization of migration and asylum policies corresponds to Turkey’s internalization of a rights-based approach up until the eruption of the Syrian civil war in 2011. He argues that the path dependent, ethno-cultural, and religious logic in receiving and welcoming Syrian refugees, a logic based on the discourses of ‘guesthood’ and the ‘Ansar spirit’, has propelled de-Europeanization dynamics.

In the final chapter of Part III, Chapter 15, Nicolò Sartori assesses the EU–Turkey relationship from the perspective of energy relations. In his contribution, Sartori places significance on the key energy policies of both parties and the main bilateral dynamics in the energy domain. He argues that energy security was often considered as a domain where mutual interests bore great potential to trigger convergence between the EU and Turkey. However, his analysis finds that significant differences remain regarding both actors’ energy profiles and policy priorities. The chapter identifies different periods of convergence, stagnation, and controversies between the EU and Turkey, the latter related to the disputes in the Eastern Mediterranean. In his contribution, Sartori also shows how new dialogue formats on energy cooperation were institutionalized between Turkey and the EU, despite Turkey’s ambition to exclusively connect the field to the accession process.

In the concluding Part IV of the volume, we, the editors, aim to harvest the conceptual, analytical, and empirical findings of the individual chapters in view of an overall assessment of EU–Turkey relations (Reiners & Turhan, Chapter 16). By taking up the guiding questions of the volume, the chapter condenses key insights derived from theories and concepts, institutions, and policies and reflects on the different periodizations of the relationship. In the next step, we assess EU–Turkey relations against a set of fundamental, mutually reinforcing enablers of cooperation and look at endogenous, exogenous, and bilateral determinants that are likely to shape the relationship in the future. The synoptic analysis also aims to translate the new complexities that epitomize the bilateral dialogue for the academic and political debate. In this context, the chapter not only presents terms of reference for the reinvigoration of cooperative trends in EU–Turkey relations but also points out the up-and-coming avenues for the future research agenda of EU–Turkey studies.

We hope, and are confident, that this volume can make a sustainable contribution to advance the understanding of EU–Turkey relations, on the one hand, and the development of EU–Turkey studies as a field of analysis at the intersection of EU (integration) studies, International Relations, and global governance studies, on the other. The individual political agendas of the EU and Turkey, as well as the common challenges at the regional and global level, are too complex, intertwined, and important to ignore the fundamental need for both intensified cooperation and deepened analysis.