Introduction

One of the main goals of social theory is to make the future more explicable by using accumulated knowledge. However, accumulated social knowledge has some ontological and epistemic limits, and if we contribute more theoretical dimension to this knowledge, we can improve its explicability about the future. In this regard, for example, ‘institutionalism’ has recently emerged as a credible social theory with the ambition to make international actors’ future behaviour more explicable [1]. Particularly, the main institutionalist approaches assume that stability/continuity should be a more common feature of an institutionalization process than instability/fluctuation. To give this in detail, Rational Choice Institutionalism (RCI), Historical Institutionalism (HI), and Sociological Institutionalism (SI), as the main institutionalist approaches, have a common tendency ‘to equate institutions with stability or durability’ [2]. From the RCI’s perspective, the logic of consequentiality encourages rational nation states to continue the initiated institutionalization process (otherwise alternative costs will be higher). HI perceives nation states as historical actors; thus, it is more likely that they continue to follow the historical path opened by a historical institutionalization process (alternative paths are unknowable and costly). SI argues that nation states are individuals of the international society; therefore, the logic of appropriateness drives them to follow the norms that emerge as outcomes of an institutionalization process (individuals are the products of the social settings) [3,4,5,6]. In other words, these institutionalist approaches assume that ‘change’ is an anomaly for an institutionalization process [7, 8]; thus, the future of any institutionalization process should be stable after its initiation if it does not face any exogenous shocks. In this regard, even the influential scholars who locate on the different sides of the International Relations (IR) spectrum share this idea on institutional change (change comes through exogenous shocks) (e.g. see [9, 10]).

If change is an anomaly and occurs due to rarely happening great shocks (e.g. the Second World War) as what the above-mentioned institutionalist approaches argue, we should be living in a more stable social world, but we are witnessing the opposite. At this point, the European Union might be given as a sui generis example in the world which arguably offers a more stable future for its members. However, the recent developments like the Brexit, sovereign debt crises and rising secessionist movements (e.g. the Catalonian case) have showed that the EU is actually not as stable as what institutionalist theory assumes. For instance, instability and uncertainty have become popular concepts in the recent studies on the future of the Eurozone in the wake of the Eurozone crisis (e.g. see [11,12,13,14,15]). Therefore, it could be argued that a continuity-oriented assumption might limit our understanding on institutional change (and so on its future) [16], and we need further studies exploring the potential dynamics which might cause instability in the future of an institutionalization process.

In this regard, the literature has some academic discussions placing emphasis on the potential dynamics of an institutional change; however, they mainly concentrate on whether change is abrupt (e.g. see [17]) or incremental (e.g. see [18,19,20]). To some extent, this discussion enriches our knowledge of institutional change. To illustrate, the incremental change understanding concentrates mainly on endogenous dynamics as a reason behind a gradual institutional change, and the abrupt change (the punctuated equilibria) approach points out the possibility of an institutional birth as an outcome of an abrupt/exogenous change [21]. However, despite this contribution, these approaches on institutional change still share the above-mentioned assumption that any institutionalization process has a strong tendency to stabilize itself in the future (regardless of its origin: abrupt or incremental) ‘because institutional stability is underpinned by many factors and changing a whole institutional system is inherently difficult’ [22]. However, these approaches on the dynamics of institutional change still poorly consider instability/uncertainty as another potential future outcome of an institutionalization process.

As a response to this need, this article aims to contribute a new dimension to the theoretical discussions on the phenomena: change from an institutionalist perspective. Particularly, the article argues that an institutionalization process contains several parameters which have close connection with both endogenous and exogenous dynamics (also see [23]). Therefore, once one of these parameters evolves into a conflictual phenomenon, it has a potential to cause subtle drifts preventing stability and produce instability in an institutionalization process [24]. To make this elusive theoretical argument clearer, it might be a good strategy to focus on the European integration process. The European integration process actually contains the mentioned conflictual parameters although there are plenty of studies in the literature which associate ‘European integration’ with ‘stability’ (e.g. see [25,26,27,28,29,30,31,32,33]). To illustrate, the institutionalization of the EU-Turkey relationship has arguably produced more instability but less stability since 1959 when Turkey applied for full membership. Moreover, if instability as a common feature of the institutionalization of the EU-Turkey relationship is analysed further, it might be seen that migration as a conflictual parameter plays a significant role in it. For instance, although a potential Turkish migration flow is historically given as one of the main reasons behind the rejection of Turkey’s full membership to the EU, the irregular migration flow (Syrian asylum seekers) as an exogenous shock forced the EU to agree on a plan giving the Turkish citizens free travel right through the Schengen Area. Thus, the analysis of migration as a conflictual parameter in the institutionalization of the EU-Turkey relationship might provide further theoretical knowledge, which might be used to make the future of the European integration in particular and our knowledge of institutional change in general more explicable.

To this end, the first section focuses on how the immigration issue has become a conflictual parameter in the institutionalization process of the EU-Turkey relationship. Later on, the second section concentrates on how migration, as a dynamic phenomenon with a strong connection with both endogenous and exogenous parameters, makes the EU-Turkey institutionalization process more open to change and instability.

Migration as a conflictual parameter in the EU-Turkey relationship

An institutionalization process is under the influence of the complex interactions between exogenous and endogenous dynamics in the social world. Therefore, endogenous dynamics might play an important role in an institutional change as well as the exogenous shocks [23, 34]. If we conceptualize institutional change as a transformation from one institutional structure to another one, change might be considered as a temporal issue and stability as the permanent nature of this process. However, instability might prevail over stability in an institutionalization process. The above-mentioned complexity might result in particularly conflictual parameters in an institutionalization process which prevent it from a clear transformation from one structure to another one. For example, Streeck and Thelen [35] point out drifts as a reason for change ‘in the way the institution works out in its social enactment by leaving its structure unchanged’ [36]. According to this drift understanding, if the outcomes of an institutional structure are negatively changed, the actors’ attitudes towards this structure also change ‘by leaving its structure unchanged’ (ibid.). Although this approach still perceives drifts as a way for a gradual transformation (from one institutional structure to another one), ‘externally induced policy drift may sometimes be wholly inadvertent’ due to the complex interactions between exogenous and endogenous dynamics [37]. If we analyse the EU-Turkey relationship from this point of view, we can see that external changes historically evolved the migration issue into a conflictual parameter in the institutionalization of the EU-Turkey relationship, and this caused a drift making instability the main feature of the institutionalization of the EU-Turkey relationship. To illustrate, even though Turkey’s relationship with the EU as a candidate country continues according the EU’s legal framework, Turkey is treated differently compared to other candidates from the Central and Eastern European countries (the current and former candidate countries), and the migration issue as a conflictual parameter plays a significant role in this difference/drift. Thus, it becomes important to understand how the migration issue has gradually become a conflictual parameter in the institutionalization of the EU-Turkey relationship.

As the mainstream institutionalist approaches assume (RCI, HI and SI), the Second World War (the WWII) as a great shock caused a significant change in Europe’s political atmosphere and the European integration became an important outcome of this change [38]. The WWII also significantly affected Turkey’s relationship with the Western European countries. Turkey applied for the full membership to the European Economic Community (EEC) in 1959, and the parties signed Ankara Agreement in 1963 which became the cornerstone for the future institutionalization of the EU-Turkey relationship [39]. Moreover, the Western European countries sequentially signed ‘guest worker’ agreements with Turkey in the 1960s (e.g. the West Germany, France, the Netherlands, Austria, Belgium, Sweden) due to the severe labor force shortage that they faced in the post-war era [40]. Therefore, a stable institutionalization might be expected after those significant agreements, but it did not happen mostly because of the oil crisis in the 1970s. In other words, as noted above, the oil crisis as an exogenous shock caused a significant drift in the institutionalization process of the EU-Turkey relationship because this shock transformed the Turkish immigration from a positive feedback to a negative one for the Western European countries/societies, and their attitudes towards Turkish immigrants changed by leaving the previously formed structure unchanged.

From an RCI perspective, the guest worker agreements between Turkey and the Western European countries triggered an economic interdependence between the parties. The war-torn Western European countries needed Turkish labour force, and Turkey needed the remittances of its emigrated workers [40]. For example, the Turkish government underlined the importance of those remittances to alleviate the country’s severe balance of payment problem in the Second Five-Year Development Plan (covering the period from 1968 to 1972) [41]. The Turkish immigrant workers also became a structural necessity to maintain the stability of the Western European labour market within a period from the 1960s to 1975 [42]. However, this mutual benefit environment was disturbed by the oil crisis at the end of the 1970s. According to RCI’s assumption, if an institution does not perform in line with its functions which were previously determined by rational actors, these rational actors seek to end the institution [43]. Therefore, when the oil crisis as an exogenous shock wiped away the pareto-optimality in the guest agreement with Turkey, the first reaction of the Western European countries was to break their agreements with Turkey. However, this did not stop the immigration inflow from Turkey to the Western European countries. The oil shock also negatively affected the Turkish economy; therefore, the Turkish workers chose to bring their families to the host European countries instead of returning home. As a result, family unification became a new way for the Turkish immigration to the Western European countries, and the Western European countries had to ratify this kind of immigration. In other words, the oil shock as an exogenous shock did not end the Turkish immigration but shifted its raison d’être from economics to human rights (the guest worker agreement to family re-unification) (also see [44]). Therefore, the Western European countries’ rule of law-centred legal structure (e.g. the Article 8 of the European Convention on Human Rights) prevented them from behaving rationally in an economic term (disposing unnecessary labour force). In a Swiss novelist’s words, the Western European countries asked for disposable labour force but human beings arrived in the Western European countries (Max Frisch in [45]), and no country could govern the Turkish immigration process as an economic issue despite their initial intention to do so. As a result, an economic interdependence triggered a spill-over effect in the institutionalization of the EU-Turkey relationship; however, this effect did not smoothly deepen the relationship but made it more fluctuating and less predictable.

Although HI and SI use a socio-psychological context instead of a rational economic one while explaining the relationship between individual and institution, their continuity assumptions also cannot properly explain this case. Firstly, from an HI perspective, increasing returns might be given as to why the Turkish immigration continued after the oil shock, and HI’s path-dependence assumption also indicates that stability should be the main feature of the post-oil shock era. However, despite this expectation, the initial design of the guest worker agreements actually opened a conflictual path which produced more fluctuation than stability in the new era. As noted above, the guest worker agreement defined Turkish immigrants as disposable labour force, and a temporary framework was designed accordingly [46]. For instance, the Turkish workers lived in mass lodging camps closer to their work areas (mines, constructions areas, factories) and they were highly isolated from the host societies [47]. Therefore, the opened path as an outcome of the guest worker agreements did not allow starting an integration process between the Turkish immigrants and the European host societies, and when the issue of the family unification emerged as an unintended consequence of the oil shock, a deep anomaly emerged in the new path. A path designed for ‘disposable labour force’ produced a permanent (family) immigration phenomenon for the Western European countries [44, 48].

Random social interactions between the Turkish immigrants and the host European societies also failed to institute logic of appropriateness contrary to what SI argues (e.g. see [49]). SI assumes that individuals unconsciously adapt themselves to the structure where they live [50]. However, the family unification brought the host societies an institution (Turkish family) but not individuals who were weak to refuse the broader structure’s norms. In other words, the elements of an institutional environment might have been easily transmitted to the new individuals coming in [51], but not to the new comer institutions, and the Turkish family as an institution was much stronger and more deliberative than any individual to maintain its own norms and cultures. For example, after carrying out an empirical research on the Turkish immigrants in Germany at the end of the 1980s, Nauck [52] found a remarkable correlation between the family structure and personnel integration of the Turkish immigrants. In this regard, as DiMaggio and Powell [53] argued, Turkish families (smaller institutional units) get the same set of the broader Turkish cultural structure (bigger institutional environment). In addition to this, the Turkish family is not only a strong institution shaping Turkish individuals’ way of life [54,55,56] but also it is under a significant isomorphic influence of broader ‘Turkishness’ environment (customs/norms/cultures). Therefore, the Turkish family became an institutional bridge to continue Turkish identity/culture and customs in the host countries [57]. For instance, Soysal [58] found that the Turkish immigrants developed their unique social settings in the host countries. Furthermore, although the end of the cold war as another external shock increased ‘immigration pressure’ on the Western societies and increased anti-immigration sentiments further, the Turkish immigration towards the region continued mainly through family formation [59]. As a result of this fact, Turkish families gradually developed Turkish ghettoes providing an effective social/cultural/economic setting for maintaining a Turkish identity (ibid.). For example, Mandel [60] argues that ‘for many Turkish Germans of Kreuzberg,Footnote 1 other places in Berlin remain unplotted on their cognitive maps’. Thus, the Turkish immigration process via family re-unification/formation created a logic of conflict causing fluctuation in the institutionalization of the EU-Turkey relationship but not logic of appropriateness (harmonization of the Turkish immigrants in the host European societies).

As a result, it could be argued that the evolution of the immigration issue as a conflictual parameter made the institutionalization of the EU-Turkey relationship more unstable. When Turkey applied to the EU for full membership, a possible Turkish immigration inflow to the EC emerged as one of the main obstacles to Turkey’s full membership [61, 62]. For example, the immigration issue was one of the main reasons behind the German Chancellor Kohl’s opposition to Turkey’s full membership in the 1990s [63]. However, the end of the Cold War as an unexpected great shock changed the international atmosphere, and this change was perceived as an excellent chance by the then European leaders to make the EU a soft world power. In this regard, particularly Schroeder and Blair as influential policy entrepreneurs/leaders perceived Turkey’s full membership to the EU as an important step to achieve the mentioned goal, and they played an important role in Turkey’s beginning the accession negotiations with the EU [64, 65]. However, although the end of the Cold War as a great shock gave those policy entrepreneurs a chance to change the European institutionalization process according to their own priorities (see [66]), the mentioned conflictual parameter became a significant factor limiting those entrepreneurs’ policy implementation capacity. For example, in 2005 when the accession negotiations between the EU and Turkey commenced, 63% of the EU people did not support Turkey’s EU membership due to a possible immigration flow from Turkey [67]. Moreover, the migration issue as a conflictual parameter played a significant role in the exclusion of Turkey from the EU’s great big bang enlargement (towards the Eastern Europe) because this parameter made European people’s ‘permissive consensus’ not applicable for the Turkish case. As a result, the evolution of migration issue into a conflictual parameter became an efficient legitimacy tool behind an anti-Turkish membership policy in the EU, and several leaders like Angela Merkel and Nicolas Sarkozy intensely used a potential migration flow from Turkey to Europe as one of the main reasons behind their ‘privileged partnership’ offer to Turkey [68, 69].

At this point, it might be considered that migration as a conflictual parameter offers a status quo for the EU-Turkey relationship. However, as noted in the previous section, a conflictual parameter is a dynamic phenomenon which makes an institutionalization process highly sensitive to exogenous changes. Thus, when the irregular migration flow to the EU broke out due to the Syrian Civil War, the way to comprehend the immigration issue in the EU-Turkey relationship changed as well. The new international setting made the Turkish immigration issue more acceptable by the EU leaders. In particular, the EU leaders accepted the free travel of Turkish citizens across the Schengen zone even without Turkey’s full membership to the EU in return for Turkey’s admission of the Syrian refugees/asylum seekers. For example, Merkel argued that ‘[…] we have to work together more closely with Turkey for a number of reasons - just think of the civil war in Syria, the fight against Islamic State or the illegal migration’ [70]. Therefore, it could be argued that the migration issue is not only a conflictual parameter causing a drift in the institutionalization of the EU-Turkey relationship but also a dynamic phenomenon which makes the mentioned institutionalization more open to change/uncertainty, and this is analysed in the following section.

Migration as a dynamic phenomenon causing fluctuations in the EU-Turkey relationship

Migration in its nature is a dynamic social phenomenon; thus, it was very hard for the Western European countries to institutionalize a stable migration regime. For instance, the Cold War was the initial external atmosphere in which they institutionalized their migration regime accordingly. They developed a migration regime in a way which would challenge the legitimacy of Eastern European communist regimes. They signed the UN’s 1951 Refugee Convention and 1967 Additional Protocol, in which the definition of refuge targets the people fleeing from the Eastern communist states [71]. Within this institutional framework, refugees/asylum seekers were defined as innocent victims of oppressive communist regimes in Eastern Europe [72]; thus, asylum seeking was absolutely a human right issue. However, the end of the Cold War as a great shock eliminated the raison d’être of this structure, and immigration started to emerge as a security problem in the new era. Especially, after the 9/11 (in conjunction with the 2004 Madrid and 2005 London bombings), the migration issue was converted into a significant security problem [73]. Therefore, the evolution of the migration issue from being a human right affair to a significant security problem created an institutional anomaly for the Western European countries. On the one hand, they had a legal framework defining asylum seeking as a humanitarian issue [74]; thus, they could not forcefully deport asylum seekers because of their being law-abiding institutions. On the other hand, after the securitization of the immigration issue, the Western European nation states needed to get some anti-immigration measures to strengthen their national security.

To deal with this paradoxical situation, they benefited from the EU’s institutional framework. At the EU level, they developed a legal basis for readmission of irregular immigrants by other countries, through which the EU would govern the uncontrolled immigration without its members’ legal obligations (e.g. the principle of non-refoulement). As a result, the EU members signed re-admission agreements with 17 different countries [75], and as of 2018, the EU continues readmission negotiations with more countries, namely, Belarus, Nigeria, Tunisia, Jordan, Morocco and Algeria [76]. Within this context, the EU and Turkey signed a readmission agreement in 2014 [77]; however, the Syrian immigrant influx in 2015 made a special measure compulsory for the EU members. The Syrian immigrant influx to the EU countries had been the biggest refugee crisis since the WWII, and the control of this influx without Turkey’s help was almost impossible for the EU members as the Syrian refugees used Turkey as the main transition route [78, 79]. To illustrate, in 2015, over 1.2 million asylum seekers (more than double the number in 2014), mainly from Syria, Iraq and Afghanistan, were registered in the EU [80]. Furthermore, the Islamic terrorist attacks are one of the main reasons behind the securitization of immigration [81], and this fact made the immigration influx from Syria a more important security problem in the EU. Especially, the alleged linkage between the Paris attacks in 2015 and the Syrian refugees showed the fragility of the issue [82]. For example, according to Eurobarometer 84 [83], 58% of the participants perceived immigration as the most important problem among the EU nations in Autumn 2015 (this amount was 20% higher compared to the survey conducted in Spring 2015). As a result, the delicacy of the Syrian refugee problem made cooperation with Turkey compulsory for the EU. As noted above, even the German Chancellor Merkel needed to admit the necessity of the cooperation with Turkey in the case of the Syrian refugee crisis [84]. In this regard, the main expectation of the EU members from Turkey is that it should prevent the Syrian refugee influx as much as possible and properly implement the readmission agreement signed in 2014 [79]. However, it was not easy to convince Turkey for this heavy burden without giving significant concessions (e.g. the acceleration of the accession negotiations and free travel for Turkish citizens in the Schengen Area).

Historically, the institutionalization of the EU-Turkey relationship created asymmetrical economic interdependence in favour of the EU, and Turkey needed to pursue its interests ‘by making choices within [those] constraints’ (for further institutionalist theoretical discussion, see [85]). However, the irregular immigration crisis, as an exogenous shock, changed the constraints in the EU-Turkey relationship in Turkey’s favour. Therefore, Turkey gained relatively more power to force the other side to give concessions. As noted above, the EU members seriously needed Turkey’s help in order to deal with the immigration influx from Syria, which made them weaker at the negotiation table, and Turkey effectively exploited its advantageous position on the issue. On 29 November 2015, the EU needed to arrange a special summit with Turkey (which was an unprecedented format) to find a solution to the increasingly deteriorating immigration crisis. During the negotiations, Turkey successfully put Turkey’s bid for EU membership on the negotiation table as a condition to give concessions on the immigration issue [86]. As a response to this demand, the EU needed to promise to open a number of accession negotiation chapters without prejudice to the position of member states and the visa liberalization for Turkish citizens [87]. At this point, it is really ironic that although a mass immigration influx from Turkey to the EU is one of the most influential arguments used against the Turkish membership [88], the EU members needed to promise ‘free movement’ to Turkish citizens in return for an agreement with Turkey on the irregular immigration problem [89]. The EU also needed a summit with Turkey on 7 March 2016, and at this meeting, the then Turkish Prime Minister Ahmet Davutoglu even had an agenda-setting power. He proposed ‘the rapid return of all migrants coming from Turkey to Greece’, but in return, asked for applying the visa liberalization on an earlier date (July 2016), opening of more chapters in the accession negotiations and more money to be used for the immigrants in Turkey [90]. This is an unprecedented occasion in the EU’s history because the EU has an overwhelming power over candidates during the accession negotiations; thus, there is no way for candidates to have an agenda-setting power in the accession negotiation process [91]. However, as a result of the high importance of the immigration issue, the EU members needed to accept the plan suggested by Davutoglu on 16 March 2016 despite the criticisms of human rights’ supporters and the UN [92].

In the following era, Turkey witnessed a failed military coup attempt and several terrorist attacks. Thus, it refused to reform its anti-terror law in line with the EU standards, which is one of the visa liberation roadmap benchmarks [93]. As a result, the visa liberalization process stalled due to the division between parties on Turkey’s anti-terror law [94, 95]. At the beginning of 2018, Turkey gave a signal that it might soften its anti-terror law according to the visa liberation roadmap benchmarks, and an EU-Turkey summit took place in Varna (Bulgaria) on 26 March 2018 to improve the parties’ strained relationship [96, 97]. However, it could not break the stalemate [98] and the instability is still the main feature of the EU-Turkey relationship despite the 60-year-old institutionalization attempt.

Conclusions

The institutionalist approaches argue that stability prevails over change in an institutionalization process once it is initiated, because ‘[t]he rise of an elaborate institutional environment stabilizes both external and internal organizational relationships’ [99] and this benign environment pushes for an inexorable homogenization between parties [53]. As a result, an institutionalization process develops a resistance to change [51], and as noted above, exogenous shocks emerge as the main possible reason behind any institutionalization change. From this point of view, institutionalist theory might be seen as ‘a theory of stability’ in social science [100, 101]. Therefore, if the European integration process is analysed from this institutionalist perspective, stability emerges as the best explanation for the future of it. However, the recent developments like Brexit have showed that instability as another outcome of the European integration process should be studied to make it more explicable.

With regard to this need, this article analyses the EU-Turkey relationship by taking immigration issue as its focal point. As noted in the ‘Introduction’ section, the article argues that an institutionalization process contains several parameters with a strong connection between endogenous and exogenous dynamics, and this fact makes the future of an institutionalization process actually less predictable and more fluctuating. Firstly, as noted in the second section, complex parameters in an institutionalization process have a potential to evolve into conflictual ones, and when a conflictual parameter emerges in an institutionalization process, homogenization in it might less likely be achieved. For example, this study clearly shows that immigration evolved into a conflictual parameter in the institutionalization process of the EU-Turkey relationship and prevented homogenization despite the high level of economic interdependence between the parties. At this point, the article has found that nobody (neither the EU nor strong West European nation states) could properly govern the Turkish immigration process since its beginning; therefore, it could be argued that complex parameters originating from connected endogenous and exogenous dynamics really limit institutional entrepreneurship and might drive an institutionalization process far beyond the deliberative intentions. As a result of this, even though an institutionalization process might produce interdependence as RCI argues, this interdependence might not prevent drifts which make the institutionalization process more fluctuating and less stable. From HI’s point of view, the cognitive limitation due to complex parameters may cause path-dependence for actors; however, an exogenous shock does not necessarily change an initially formed path but might trigger instability within itself by creating endogenous conflictual parameters. To illustrate, a path opened for the temporary Turkish guest workers in the post-WWII conjuncture became a fluctuation reason in the institutionalization of the EU-Turkey relationship after the oil crisis. Additionally, putting too much emphasis on structure might not be sufficiently explicable while analysing an international institutionalization process. As SI argues, if structure has a significant influence on actors, the strong national structural influence on individuals does not fade away easily in an international institutionalization process. This case study especially shows that the transfer of the Turkish family structure prevents the random interactions between the Turkish immigrants and the European host societies from creating a logic of appropriateness as an initial step for homogenization, but the immigration of a social institution from Turkey actually resulted in a logic of conflict between the Turkish immigrants and the European host societies, which significantly leads to fluctuations in the future of the EU-Turkey relationship.

Moreover, as noted in the third section, migration in its nature is also a dynamic social phenomenon which not only prevents the EU member states from institutionalizing a stable migration regime but also relatedly makes the institutionalization of the EU-Turkey relationship more fragile against exogenous shocks. The Western European countries initially institutionalized the migration issue in a human rights framework; however, the securitization of the migration issue forces them to seek alternatives and they have become highly sensitive to exogenous developments related to this issue. In this regard, the Syrian immigrant influx in 2015 is a good example showing the sensitivity of the EU countries to the migration-related exogenous developments and how the migration issue makes the institutionalization of the EU-Turkey relations open to change. Even though the Turkish immigration issue has historically become a great reason behind the opposition against Turkey’s EU membership, free travel right was promised to all of the Turkish citizens in return for a re-admission agreement which would hopefully prevent the irregular immigration flows to the EU. In addition to Schroeder and Blair’s pro-Turkey policy, Merkel’s pro-Turkey formulation is a significant indicator suggesting that the European integration process is not only related to permissive consensus; dynamic parameters with an intertwined connection with exogenous and endogenous variables might also play a significant role in its development. However, the effects of dynamic parameters on the integration process might be in a way making it more unstable and open to change. For example, this case study clearly shows that the mentioned pro-Turkey formulation is developed by the European leaders as an immediate measure against the immigration influx despite the public opposition to Turkey’s EU membership, and the lack of public support gradually weakens the implementation of this formulation. Moreover, a change obviating the need for this formulation is also possible in the complex international environment. Therefore, it could be argued that the immediate need to respond to an exogenous shock might contribute to the fluctuation of an institutionalization process, and the post-shock era might be more unstable than what the main institutionalist approaches indicate.

Last but not least, this case study suggests that instability might be a key feature of a social institutional setting, and social theory could explain instability in the social world by giving more attention to non-linear dynamic facts [102]. Particularly, it is clear that social knowledge is needed to be acquired through numerous societal interactions (including individuals, society, social institutions, socio-physiological phenomena and history); therefore, it might be a good strategy for social scientists to give more attention to dynamic social phenomena while trying to accumulate knowledge of social life. For instance, science historically experienced a ‘paradigm shift’ from Newtonian physics to quantum physics which was devoted to understand dynamic phenomena in the universe; thus, human beings started to gain new knowledge of the universe (e.g. dark matter). From this point of view, a similar change giving more reference to societal non-linear dynamics might produce new social knowledge. In this regard, the literature related to social theory already has some contributions trying to ontologically integrate the dynamic quantum logic into social theory (e.g. see [103, 104]).

In the light of these findings, a future scenario for the European integration and the EU-Turkey relationship might be developed as follows:

The supranationalist cognitive map defining the European integration as a linear ongoing process implicitly points out a final destination for it (a federal state-like polity). However, the above-mentioned theoretical/ontological perspective suggests that the European integration contains so many intertwined exogenous and endogenous variables that it cannot be a full-fledged polity like a nation state. In other words, it could be argued that the European integration will continue as a dynamic ongoing process in the future, and its structure is open to a continual change. From this point of view, it could also be argued that the European integration process might gain more heterogeneity in time as it does not have a gravitational power (neither strong institutions nor identity, see [105]) to deal with the mentioned intertwined exogenous and endogenous variables. Moreover, the nation state is still the main actor of the integration process and they might develop different epicentres as a response to any change in the exogenous and endogenous variables. Therefore, as the differentiated integration approach (e.g. see [106, 107]) argues, it is highly possible that the European integration might gain a multidimensional and octopus-like soft-bodied structure contrary to the supranationalist ambition to achieve a Brussels-centred hierarchic institutionalization. At this point, the findings of this case study clearly support this argument. To illustrate, the EU leaders arguably ignored the EU’s norms (e.g. the human rights) while developing a re-admission agreement with Turkey as a response to the recent immigration crisis. Furthermore, as the migration influx towards the Western Europe started to be viewed as a national security issue, even the core EU members began to behave independently. For example, France, Austria, Germany, Denmark and Sweden reintroduced national border control despite the Schengen Agreement [108], and Italy has started to block foreign navy ships participating in the EU’s migrant rescue missions as of June 2018 [109]. In addition to the migration issue, the Brexit and the Eastern European members’ plea for more autonomy from the EU law (see [110]) also show the member states’ tendency to develop different epicentres within the EU system according to their own priorities.

As for the EU-Turkey relationship, the migration issue as a conflictual parameter makes the institutionalization of it highly unstable. As a conflictual parameter, the migration issue plays both a catalyst and inhibitor role in the institutionalization of the EU-Turkey relationship. Therefore, on the one hand, the migration issue could continue to become a significant factor preventing Turkey’s full membership to the EU in the near future. On the other hand, if the European integration gradually becomes more heterogeneous/multidimensional, Turkey might find a place in this fragmented structure and the migration issue might play a catalyst role in this instance. Firstly, the EU needs Turkey’s cooperation to control the future immigration crises as a geopolitical measure, and the maintenance of this cooperation requires further institutionalization with Turkey. Secondly, according to Turkey’s Ministry of Foreign Affairs [111], 5.5 million Turkish people already live in the Western European countries, and the migration has already made Turkey the EU’s de facto member because these people constitute a significant Turkish diaspora in the EU and the EU member countries again need the cooperation with Turkey for the governance of them. All in all, Turkey refuses a special partnership instead of the full membership at the movement, but the migration issue might make a differentiated membership formula a more reasonable option for both Turkey and the EU member states if the EU gains a more multidimensional and non-hierarchical structure in the future.