Internal Rebordering in the European Union: Postfunctionalism Revisited

The EU has been under severe strain as a free‐travel area. The migration crisis of the mid‐2010s and the current Covid‐19 pandemic have exerted a negative impact on the freedom of movement in the EU and the undisturbed crossing of internal borders within the Schengen area. Direct effects and long‐term consequences of the prolonged crisis have shown that the dynamics of integration, which are determined by spillover effects of transnational processes, are counterposed by a politicization of domestically‐embedded issues of security governance. This assumption underpins the postfunctionalist approach to European integration proposed originally by Hooghe and Marks. The tendency toward longstanding dero‐ gations from the Schengen regime, termed “internal rebordering,” should be juxtaposed with efforts of the European Commission toward a full restoration of the Schengen area without controls at internal borders. The argument developed in this article holds that internal rebordering has been embedded in the logic of the EU as an area of freedom, security, and justice comprising the Schengen area as its territorial manifestation. The rebordering processes in the EU and in the Schengen area have questioned the principle of “constraining dissensus” underlaying the postfunctionalist approach.


Introduction
The EU as an area in which the free movement of persons is ensured has been under severe strain over the past few years. The migration crisis of the mid-2010s and the current Covid-19 pandemic have exerted a negative impact on the freedom of movement in the EU and the undisturbed crossing of internal borders within the Schengen area. The ongoing migration crisis has shown that the dynamics of integration, which is determined by spillover effects of transnational processes, is counterposed by a politicization of domestically-embedded issues of security governance.
The challenges to and intricacies of Schengen governance have recently attracted the attention of scholars well-anchored in the study of the EU's area of freedom, security, and justice (Bellanova & Glouftsios, 2022;Ceccorulli, 2019;Colombeau, 2019;Coman, 2019;De Somer, 2020;Lamour, 2019;Votoupalová, 2020). However, these only partially satisfy the desire to arrive at a more nuanced and varied account of the trajectory of this particularly sensitive area of European integration.
In this article, the tendency toward longstanding derogations from the Schengen regime, termed "internal rebordering," is examined against the postfunctionalist framework of theoretical reflection on European integration. The migration crisis in the Schengen area has been seen as a relevant yet controversial test of the viability of the theory of postfunctionalism and the "postfunctionalist moment" (Schimmelfennig, 2014) in the history of European integration. The postfunctionalist perspective has recently been adopted in the study of migration and mobility in the EU (Schimmelfennig, 2018(Schimmelfennig, , 2021, yet its appropriateness is debatable. It has already been argued that postfunctionalism has its limits (Börzel & Risse, 2018;Schimmelfennig, 2014Schimmelfennig, , 2018Schmitter, 2009). However, from the perspective of European integration theories and security studies, a manifestation of the postfunctionalist perspective framing the dynamics of politicization of and "constraining dissensus" in the field of EU internal security governance should be seen as a valuable framework for the explanation of exceptions from the rules governing mobility within the Schengen area.
The argument developed in this article holds that internal rebordering has been embedded in the logic of the EU as an area of freedom, security, and justice with the Schengen area as its territorial manifestation. Paraphrasing Popescu (2012, p. 7), borders in the EU are political phenomena made by states to help them manage their security. Borders are a key element of security governance in its multi-level configuration linking territory to jurisdiction and political power. As such, they are hardly contested by actors at the state level and tend to avoid crisis-driven politicization.
The methodology adopted in this article is based on a qualitative analysis of legal documents of the EU, a critical assessment and interpretation of theoretical foundations of postfunctionalism, and a critical review of the scholarship in border studies. The dynamics of rebordering is assessed with the use of the process-tracing technique. Data provided by the European Commission supported the analysis of the scope of rebordering within the Schengen area.

Postfunctionalism: Politicization and Euroscepticism
Andrew Moravcsik, an eminent US scholar studying European integration, classified postfunctionalism as one of the main (baseline) theoretical frames of European integration, along with liberal intergovernmentalism and historical institutionalism (Moravcsik, 2018(Moravcsik, , p. 1649. Regardless of the rationale behind Moravcsik's typology, it must be underlined that the postfunctionalist approach to European integration has garnered considerable interest and consolidated its status as one of the most common concepts in the study of European integration (Braun, 2020, p. 928). It has been appreciated as a new research agenda seeking to better understand the intricacies and deficiencies of EU politics. Postfunctionalism was proposed originally by Hooghe and Marks (2009), who questioned the positivist kernel of neofunctionalism residing in transnational mobilization, supranational activism, and policy spillover (Hooghe & Marks, 2006, pp. 208-209;Schmitter, 2009). Likewise, they were critical of liberal intergovernmentalism because of its reductionist understanding of European integration as a bargain over the distribution of economic gains among states or business groups. As the proponents of the multilevel governance model (Hooghe & Marks, 2001;Marks et al., 1996) they argued that decision-making competences are shared by actors at different levels; therefore, state executives must accept a significant loss of control over European (i.e., supranational) policymaking. Member states maintain their strong position in the architecture of European integration as they are an "integral and powerful part of the EU, but they no longer provide the sole interface between supranational and subnational arenas" (Marks et al., 1996, p. 347).
Hooghe and Marks advocated an actor-centered approach to European integration due to the complex agenda-setting determined by the reallocation of decisions to the supranational level, diffusion of control over the agenda, and informational asymmetries. They observed that the emergence of a Euro-polity, a process accompanying the shift from state politics toward multi-level governance, was determined by party competition and interest group politics. Patterns of political contestation cultivated the dispute in the realm of European integration over the meaning and implications of national identity (Hooghe & Marks, 2004, p. 1). Hooghe and Marks emphasized that jurisdictions that people create express their national, regional, and local identities. They highlighted the disruptive potential of clashes between functional pressures at the supranational level and exclusive identity at the national level. That clash results in a politicization of European integration (Hooghe & Marks, 2018, p. 5).
Politicization leads to a constraining dissensus which limits governance by producing a mismatch between functionally efficient and politically feasible solutions. Given that governance "is determined not just by its functionality but by its emotional resonance" (Hooghe et al., 2016, p. 3), the mobilization of mass public opinion against supranational solutions imposes constraints on the performance of European institutions and policies. This augments politicization dynamics which advances in three steps: (a) a discrepancy between the institutional status quo and the functional pressures for multilevel governance, (b) the opening of a decision-making arena for mass politics, and (c) the shaping of the structure of political conflict by polarizing societies along cultural and socio-political cleavages (Hooghe & Marks, 2019, pp. 1116-1117. Postfunctionalism addresses the phenomenon of Euroscepticism by analyzing the distribution of political preferences among citizens expressed in public opinion polls. It prefers to fold the issue of European integration into the left-right dimension, highlighting an increase in the consolidation of attitudes along the liberal/nationalist opposite (GAL/TAN). The polarization of opinion distribution, boosted by national elites and political parties, has a decisive impact on identity formation (Down & Wilson, 2008). It legitimizes a constraining dissensus on the European arena, yet it does not reduce domestic political contestation. Postfunctionalism "counterposes the mobilization of exclusive national identity to functional pressures for co-operation'' (Hooghe et al., 2018, p. 2). The difference in integration outcomes is explained by variation in domestic politicization (Schimmelfennig, 2018, p. 975).

Conceptualizing Rebordering
The concept of rebordering is intimately linked to borders, mobility, and security. Broadly speaking, it addresses the functions and practices of bordering conceived as the imposition of border surveillance and control and their organization within a tailor-made management system. Hence, it reflects policy-driven security concerns provoked by human mobility, movements of goods and services, cultural diffusion, and advances in transportation and communication technologies. The "territorial exclusivity of the 'nation'-state" (Anderson, 1996, p. 5) and, thereby, the administration of its territory through control over intramural and crossborder mobilities, is augmented by borders conceived as "the physical manifestation of the sovereignty of the nation and the power of the national state to secure that nation from harm" (Hastings, 2010, p. 2; see also Paasi, 1999, pp. 19-21). Since borders are part of the territorial domain of the state, they come under the sovereign jurisdiction of the relevant judicial institutions, as well as being sites of security governance and law enforcement. As a result, they "are in fact arbitrary institutions, composed of other constituent and smaller institutions, which are designed to break-up and manage the flow of items and personnel into and out of the state" (Hastings, 2010, p. 5). Bordering practices have become increasingly reliant on technologies of surveillance, biometric identification and automatic recognition systems, and proactive intrusion-detection (Amoore, 2006;Hayes & Vermeulen, 2012;Popescu, 2012, p. 4;Scheel, 2013Scheel, , 2019. Excessive bordering, typical for times of inter-state rivalry and hostility (like during the Cold War), rampant nationalism, and cultural cleavages, constrains international cooperation and deprives nations of the substantial economic gains derived from cross-border commerce and labor mobility. This liberal argument underlaid globalization and networking, which in their turn were given a big boost by the revolutions in modern transport and communication technologies triggered by digitalization and computerization (Eriksen, 2014;Ernst & Haar, 2019, pp. 3-9;McGrew, 2020, p. 23). Globalization created a growing pressure on state borders as obstacles to modernization and barriers to global development. The neoliberal turn in the 1980s and 1990s resulted in strong trends toward debordering. An outcome of globalization as a presumably unstoppable process (Andreas, 2003;Melin, 2016), debordering has been commonly associated with the liberalization of cross-border flows of goods, persons, and capital (Newman, 2001;Popescu, 2012, p. 2). It was conceived as a constantly progressing "permeability" of borders due to the elimination and abolition of all legal, institutional, technical, and infrastructural measures which hampered or limited free movement across them (Albert & Brock, 1996, pp. 74-77). In practice, it encompassed diverse measures and activities which opened up borders, reduced or softened border controls, and even questioned boundary congruence (Jańczak, 2011). Regional free-trade areas in North America, Europe, and South-East Asia may serve as typical examples. In the most advanced regional integration conglomerates, or shared economic spaces, such as the Benelux Economic Union or the EU, the intensity of cross-border commercial flows resulted in a far-reaching facilitation of the movement of persons, culminating in the abolition of checks at internal borders. In that case, one can denominate the final outcome of the debordering processes as disbordering.
Unwanted consequences of globalization-driven debordering (such as transnational crime, terror networks, uncontrolled migration) created a need for the hardening of states' external boundaries, a heightened demand for more defensive borders (Scott & van Houtum, 2009, p. 271). Rebordering emerged as a straight and logical reversal of debordering. It put security ahead of liberty and freedom of movement and placed the emphasis on protective measures and safeguards. As Andreas (2000, p. 2) observed tartly: The celebrated debordering of the state…is far more selective than the inflated rhetoric of globalization would suggest. Debordering is being accompanied in many places by a partial rebordering in the form of enhanced policing. Even as many borders have been demilitarized in the traditional realm of national security, as well as economically liberalized to facilitate commercial exchange, they are also now more criminalized to deter those who are perceived as trespassers. Thus it may be more accurate to say that the importance of territoriality is shifting rather than simply diminishing.
From the postcolonial perspective, rebordering is a disposition enforced by the nation-states of the rich North in order to keep the Global South out (Melin, 2016, p. 71); or-as Horvat (2014, pp. 94-95) notes with regard to European integration-by the diligent North confronted with the relaxed and lazy South. From the constructivist perspective, rebordering reflects the contested meaning of territoriality in an evolving state system (Kratochwil, 1986, pp. 51-52;Ruggie, 1993, pp. 148-152). Borders and boundaries, being discursive social constructs whose nature changes over time, are marked by porousness and permeability (Newman, 2011, pp. 39-41). Rebordering entails the construction of new boundaries through discursive practices which aim at producing "the social effects of the new symbolic spaces of belonging and exclusion in the innerland" (Suárez-Navaz, 2004, pp. 1-2; see also Walters, 2006). From the neorealist perspective, rebordering means bringing the state back in as a protective shield for its sovereign authority, territory, and jurisdiction. Security, control, and resilience at the borders are bounded with policies for tackling external threats, such as armed aggression, terrorist actions, or uncontrolled migration (Coaffee & Rogers, 2008, p. 113).
Rebordering has a physical component. Although it is anchored in human geography, in socio-spatial topologies, it definitely involves power relationships and political regimes established by sovereign polities and (safe)guarded by states and their relevant institutions. Hence, bordering is seen here as sites of power intimately linked to physical separators which form part of a technical infrastructure of management, surveillance, and ordering. Consequently, rebordering results in coercive control, policing, and criminalization targeting, essentially, migrants (Nevins, 2014). It also creates sites of exclusion, discrimination, and humanitarian tragedy (Furedi, 2021, p. 1).
Rebordering can be categorized into exclusionary (external, outward-looking) and inclusionary (internal, inward-looking) forms. The difference lies in the instrumental use of borders by state authorities for risk management and security governance. External rebordering entails the establishment or reinforcement of protective and regulatory means of principally addressing and affecting actors residing outside a state territory. It encompasses physical (walls or fences at the border), normative (immigration law, trade agreements), and administrative (visa instruments, border checks, return decisions) measures. Internal rebordering consists of activating state mechanisms and resources within the state territory. It is partly a reaction to the failures or deficiencies of external rebordering, partly a method of managing risks emerging within the state under the influence of external factors. Internal rebordering embraces exceptional measures affecting certain categories of the population (both indigenous and immigrant), such as restricted access to and limited movement in some parts of the territory, or the establishment of sites of exclusion for migrants, especially those seeking international protection. It also includes heightened security measures over the entire territory, such as an increased activity of law enforcement institutions, more frequent checks of people and goods, or rapid interventions in the case of threats to public order and internal security.

Rebordering Practices: Eroding Schengen as a Free-Travel Area
Rebordering has been an inherent element of the Schengen area. It has also been part of the EU's area of freedom, security, and justice. The rationale behind the Schengen area was based on a functional connection between debordering and rebordering (Zaiotti, 2011). The Schengen agreement stipulated that "with regard to the movement of persons, the Parties shall endeavor to abolish checks at common borders and transfer them to their external borders" (Agreement between the Governments of the States of the Benelux Economic Union, the Federal Republic of Germany and the French Republic, 2000, art. 17). The Convention implementing the Schengen Agreement (CISA) proclaimed in article 2.1 that "internal borders may be crossed at any point without any checks on persons being carried out." In an outright juxtaposition, according to article 3.1, "external borders may in principle only be crossed at border crossing points and during the fixed opening hours." In addition, member states were obliged to "introduce penalties for the unauthorised crossing of external borders at places other than crossing points or at times other than the fixed opening hours" (Convention implementing the Schengen Agreement of 14 June 1985June , 2000.
The principle of the abolition of control at common borders is therefore subject to flanking measures and internal safeguards. The former, outlined in the CISA, underpinned the concept of integrated border management at the EU's external borders. It brought about the establishment of Frontex (now the European Border and Coast Guard Agency) and the tendency toward the closer cooperation of national border guards in surveillance and control of the external borders. The latter is key to following the logic of internal rebordering. It emphasizes national security interests, threat prevention, and risk management across Schengen as the free-travel area. At the time of negotiating CISA, states-parties to the Schengen agreement were well aware of the sort of "collateral damage" which might be produced by inefficient means and capacities at their external borders. They decided to build safety valves in mechanisms regulating the functioning of Schengen as a security area. Article 2.2 of CISA stipulated the following: "Where public policy or national security so require a Contracting Party may, after consulting the other Contracting Parties, decide that for a limited period national border checks appropriate to the situation shall be carried out at internal borders" (Convention implementing the Schengen Agreement of 14 June 1985June , 2000.
It is important to underline the point that the decisions concerning rebordering remained with member states. They were entitled to make unilateral decisions on the reintroduction of checks at their internal borders. They were only required to notify the other states about the planned reinstatement of checks or about the urgent circumstances of the adopted measure. However, the provisions of Article 2.2 of CISA were conceived as the derogation clause and thereby their activation had to be considered as a measure of exception (Decision of the Executive Committee of 20 December 1995December , 2000. Indeed, in the early period of the Schengen integration, reinstatements of checks at common borders were occasional and principally related to political activities in the territory of member states. The incorporation of the Schengen acquis into the EU by virtue of the 1997 Amsterdam Treaty and the progressing partial communitarization of the Schengen cooperation did not exert a strong impact on the principles and mechanisms of rebordering. Despite the adoption of a regulation establishing the Schengen Borders Code (SBC), which repealed CISA provisions on internal and external borders, the rules stayed unchanged with one significant exception: The European Commission also had to be notified of intentions or decisions to reintroduce border checks (Regulation of the European Parliament and of the Council of 15 March 2006March , 2006. The frequency of decisions on the reinstatement of checks was relatively low in the first two decades after the emergence of the Schengen area. As Groenendijk (2004, pp. 158-160) proves, in the years 2000-2003 member states sent 31 notifications of their intention to reinstate checks at internal borders. Two emergency situations occurred due to migration pressure at internal borders which resulted in a short-term closure of some sections of the border. Of 33 cases of the reinstatement of border checks, 25 were necessitated by planned toplevel political meetings.
Between 2006 and 2014, despite the Eastern enlargement and the extension of the Schengen area on the territory of 26 countries, internal border checks were reintroduced 36 times (European Commission, 2021b;van der Woude & van Berlo, 2015, pp. 69-74). However, a brief episode at the Franco-Italian border in April 2011 sparked a political debate on internal rebordering as a security measure for preventing uncontrolled flows of immigrants (Carrera, 2012). The incident at Vintimille/Ventimiglia, when France closed the border for several hours and reintroduced controls in order to prevent the entry of large numbers of Tunisian nationals travelling by train to Marseille, catalyzed the discussion on the effectiveness of the Schengen mechanisms (Zaiotti, 2013). The French and Italian governments insisted on a revision of rules for the reintroduction of checks at internal borders and on the improvement of the monitoring mechanism (Schengen evaluation). The Commission agreed to revisit the key elements of the Schengen legal regime and, in September 2011, brought forward the so-called Schengen governance package. The Commission's proposals took the form of amendments to the SBC and to the evaluation mechanism. Adopted in October 2013, they contained important changes in the rebordering scheme (Coman, 2019). The two existing modes of reintroduction of checks, the foreseeable and the urgent ones, were modified in terms of time scales (extension of temporality) and were supplemented by a third mode concerning exceptional circumstances in which the overall functioning of the Schengen area is put at risk. In that case, border control may be reintroduced for a period of up to six months with an option of prolonging that period up to three times if the exceptional circumstances persist.
The loosening of restrictions imposed on member states with regard to their rebordering powers should be considered as a safeguard in case of inevitable migration pressures or a rapid proliferation of grave security threats, such as terrorism or serious and organized crime. It anticipated the migration imbroglio arising in the early 2010s as a consequence of upheavals in some Middle East and North African countries (the so-called Arab Spring) and the continuing instability in war-torn regions of Asia and Africa (Guild et al., 2015). Since the outbreak of the migration crisis in the autumn of 2015 up to the beginning of the Covid-19 pandemic in early 2020, internal border checks were reintroduced 82 times. More importantly, several member states turned their decisions on the temporary reinstatement of border controls into standard practice. The case of France was excep-tional because the decision was provoked by the terrorist attack of 13 November 2015, the state of emergency proclaimed, and the continuous terrorist threat. Other countries, such as Germany, Austria, Denmark, Sweden, and Norway, used interchangeably relevant provisions of the SBC as a legal basis for the continuous maintenance of border controls (Wolff et al., 2020(Wolff et al., , pp. 1130(Wolff et al., -1131. Internal rebordering practices within the Schengen area during the 2015-2016 crisis were prompted by the refugee issue. The number of asylum applications lodged in EU member states doubled in 2015 in comparison to 2014 and tripled in comparison to 2013 (Eurostat, 2021). Contrary to Schengen governance, the Dublin system anchored the international protection of refugees in the territory of a given state considered responsible for refugee protection in accordance with EU law. The latter embraced several EU legal measures which constituted the core of the Common European Asylum System (CEAS), completed in 2013. The Dublin III regulation determining the member state responsible for examining an application for international protection was the key component of CEAS. It allocated responsibility for providing temporary assistance to asylum seekers and eventually granting them refugee status to respective national authorities. Therefore, bordering was an inherent feature of the EU's common asylum policy, epitomized by CEAS and extended over the Schengen area.
The huge inflow of asylum seekers in the autumn of 2015 engendered an enforced debordering on the external frontiers of the Schengen areas. Irrespective of the causes of that phenomenon (which varied from country to country), it had serious consequences for CEAS. Watching the refugee issue through the postfunctionalist lens, it is important to zoom in on the specific interplay between the two critical attitudes: permissive consensus and constraining dissensus. The turbulent circumstances accompanying the massive and largely uncontrolled influx of asylum seekers from the territories of Turkey and Libya facilitated the widespread acquiescence of the governments of EU member states to mass arrivals. The humanitarian imperative, enhanced by dramatic media coverage of the tragedy of displaced people forced from their homes by wars and protracted violent conflicts, was largely undisputed. The rapidly growing death toll at sea and the heart-breaking story of the lifeless body of a three-year-old boy named Alan Kurdi coincided with the decision of the German federal government in mid-September to adopt a "refugees welcome" policy (Adler-Nissen et al., 2020, pp. 75-76;Maricut-Akbik, 2021). In Brussels, the Council of the EU adopted on 22 September 2015 a controversial plan of internal relocation of 120,000 asylum applicants from Greece and Italy to other EU member states over two years (in addition to 40,000 "persons in clear need of international protection" who were subject to a relocation mechanism approved in June 2015).
The dynamics of this enforced debordering curbed the strong tendency toward permissive consensus with regard to migrants. Fear of successive waves of asylum seekers spilling chaotically across Europe was augmented by reports on the booming human smuggling industry in the Mediterranean region and warnings of terrorist and criminal threats from individuals and crime networks (Europol, 2016;Europol & INTERPOL, 2016). Many EU citizens were concerned with the negative repercussions of the surge of refugees for security, economic wellbeing, and public order (Gorodzeisky & Semyonov, 2021;Servent, 2019;Wike et al., 2016). The permissive consensus on the reception of asylum seekers was rapidly waned, giving way to constraining dissensus over the application of CEAS, refugee relocation, and, most importantly, the keeping of internal borders in the Schengen area wide open. Politicization of the refugee problem, bolstered by anti-immigrant, right-wing parties, and the concomitant securitization of the migration issue, owing to law-enforcement authorities and xenophobic social circles highly active on social media, led to a new permissive consensus having a specific defensive and deterring nature. Internal rebordering became the key element of the politicized agenda of the EU in the years following the migration crisis. With the twilight of Germany's hospitality agenda, the temporary reintroduction of checks at internal borders by several member states, the collapse of the relocation scheme, and the shift of the center of gravity to the management of external borders, the EU's common asylum policy fell victim to the permissive consensus regarding the rebordering of the Schengen area.
The Covid-19 crisis has provided additional arguments for the postfunctionalist "reverse" with regard to border management in the EU. The first weeks of the slow-burning crisis were marked by chaotic attempts on the EU level at controlling the rapidly proliferating pandemic (Bossong, 2020;Schmidt, 2020;Stępka, 2022;Svendsen, 2021;Tesche, 2022;Vila Maior & Camisão, 2022). Constraining dissensus was preponderant in key areas of supranational decision-making, such as health (distribution of medical supplies, vaccination programs), economy (emergency measures, recovery funds), and political coordination. However, restrictions on mobility as safeguards against the rapid transmission of Covid-19 were widely accepted and immediately applied. Permissive consensus was built around internal borders as first-line security arrangements in the Schengen area (Vila Maior & Camisão, 2022, pp. 85-90).
Therefore, the Covid-19 crisis has produced a dramatic increase in the number of reintroduction notifications. From the very first decision on the reestablishment of border controls because of Covid-19 taken in mid-March 2020 to the present day (as of 7 April 2022), the number of such decisions amounted to 183. From a legal and a political point of view, these decisions are hardly questionable (Montaldo, 2020, p. 527). Moreover, the dynamics of the Covid-19 pandemic project a more prolonged period of exceptional measures, including mobility restrictions and internal border checks. Proposals formulated by the European Commission (2021a) for a full restoration of the Schengen area as a free-travel zone do not principally question the right of member states to reintroduce internal border controls. The Commission calls for more coordination at the European level, proportionality of border checks, and their introduction as the last resort. This constitutes an additional argument for the durability and systemic purposefulness of internal rebordering in the Schengen area.

Conclusions: Postfunctionalist Flaws Revisited
The 2015 migration crisis marked a turning point in the perception of the free movement of persons in the EU and within the Schengen area. In late 2015 and early 2016, nine Schengen countries temporarily restored controls at their internal borders. Later, six of those countries maintained checks at all or selected sections of their internal border, making it a permanent practice. The Commission's failure to take appropriate action to fully restore unrestricted mobility in the EU, coinciding with the unsuccessful revamping of the CEAS and the controversial handling of tensions at the EU's external borders, supported the arguments for the rebordering of Schengen and de-Europeanization of the EU's area of freedom, security, and justice. It was also argued that the migration issue caused a high degree of polarization across Europe, enhancing thereby the politicization of the Schengen regime. As Hooghe and Marks (2018, pp. 10-11) ascertained, "Postfunctionalism places the migration crisis in the context of domestic politicization in order to explain why transnational pressure was weak and why so many governments were unwilling to cooperate." In accordance with the postfunctionalist argument, the migration crisis triggers polarization within the European polity, which tends to politicize the crisis by referencing national identity, aligned with state jurisdiction. A resort to emergency measures, such as the reinstatement of checks at the common borders, is considered a weakness of transnational actors.
Although the European Commission has not been assertively executing its monitoring tasks and tools provided by the Schengen evaluation system (Montaldo, 2020, p. 529), it has regularly addressed the issue of rebordering and put forward several propositions, including those contained in a strategy toward a fully functioning Schengen area. Rebordering has also been discussed in the European Parliament (Bélanger & Schimmelfennig, 2021). The politicization accompanying the rebordering discourses in these supranational institutions has challenged national identities and put the issue of the integrity of Schengen high on the European agenda. However, it did not question measures of internal rebordering; rather, it pointed to cross-border and supranational mechanisms of cooperation across the EU.
The limited scope of the politicization of external and internal rebordering in EU institutions and national authorities shows a permissive consensus rather than a constraining dissensus. This is due to the fact that rebordering has been functionally embedded in Schengen as a free-travel area and as part of the EU's area of freedom, security, and justice from its very beginning. Although it might be perceived in terms of contested sovereignty within Schengen governance (Votoupalová, 2019, p. 84), a complete debordering has never taken place in the Schengen area.
Schengen rebordering demonstrates that crisisdriven politicization may be part of a long-term adaptation process aiming to mitigate the constant friction between supranational imperatives and national dissent without eradicating it from multi-level mechanisms of security governance in the EU. Bordering has been part of the EU's security policy and as such is more prone to securitization than politicization. The internal rebordering rules defined in the SBC respond to the national security interests of member states, yet they also emphasize the need to adopt this mechanism in exceptional circumstances which put the overall functioning of the Schengen area at risk. Such a precautionary measure transfers responsibility for safeguarding cross-border movement to member states who become "guardians" of the Schengen principles. My argument strengthens Eilstrup-Sangiovanni's (2021, p. 464) point that, due to the particular nature of European integration, "external re-bordering presents a doubtful alternative to internal re-bordering in the present EU context." It also disputes the assumption made by Genschel and Jachtenfuchs (2021, p. 350) that "postfunctionalism posits a basic tradeoff between the functional scale of governance and the territorial scope of community." Regarding internal rebordering in the EU, one can argue that postfunctionalism undervalues the territorial level of European governance in which networks and connectivities between national actors and supranational entities tend to avoid politicization. This concurs with Börzel and Risse (2018), who noted that postfunctionalism tends to underestimate the resilience of the EU. Rebordering may be interpreted as a mechanism designed to ensure resilience during crises or emergencies which are fundamentally depoliticized and are coped with for the sake of restoring full-fledged cooperation and integration across the EU.