Keywords

3.1 Introduction

Over the course of the last decade, the analysis of irregular immigration and of migratory controls has led to a fruitful debate among disciplines in the social sciences. At the heart of this discussion, which has also resulted in new dialogue between migration and border studies, lies the analysis surrounding the new functions and the new spatial dimensions of border action, as well as the emergence of new ways of implementing migratory controls that go beyond state action and involve interstate cooperation.

The border has become increasingly visible as a setting where initiatives aimed at controlling irregular immigration are tested, conferring, as in the case of the European Union, an analytical centrality to some neighboring territories. The purpose of this paper is to reflect on the connection between migration and border studies by considering the role given to borders when analyzing international mobility from various disciplines, with the backdrop provided by the analysis of migration control initiatives undertaken along the southern border of Europe and in Spain over the last decade. The paper is structured into three parts. In the first, we present a brief description of how the border is viewed in different disciplines and its role in modulating migration theory. We also highlight the increasing reference to migration phenomena in border studies. Migrations and borders are the two elements that have shaped the analysis into the implementation and development of Spanish and European migration control policies in the last two decades, which are described in the second part of the paper. This action has been characterized by a series of guidelines that are best described by the attributes of externalization, communitization, and technologization. It has also been subject to political scrutiny by social organizations in the receiving societies and by the international community in response to actions that are seen as violating the fundamental rights of migrants. An empirical analysis of the Spanish case in the third part allows us to put forth a series of considerations concerning the scope that the study of border control can have on the expansion of migration theory. To do so, we focus on the factors that explain the restriction and containment of human mobility and on the spatial dimension that lies at the core of this type of public intervention.

3.2 Interrogating Migration Control and Borders

3.2.1 Borders and Social Sciences

The border has been a key category for the social sciences since the late nineteenth century, with the modern configuration of the nation and state building processes. After a certain decline in its analytical centrality in the 1970s and 1980s, resulting mainly from the emergence of studies on globalization, the new social and political meanings of borders have reemerged with vigor among the theoretical concerns of academia, associated with, among others, the analyses of migratory dynamics. In this section, we will briefly focus on the links that exist between migration and border studies before continuing on to consider the most significant areas of inquiry into borders and migration control in social sciences. Although this review is not intended to be exhaustive, it shows how the study of borders is able to nourish dialogue between different disciplines.Footnote 1

At the intersection of migration and border studies, and the bodies of theory that supply both areas, is the centrality of border action in modulating human mobility. Borders appear in migration theory through their role as one of the factors that explain the dynamics of mobility between areas of origin and destination and the distinction between international and internal migrations. In border studies, the analysis of borders has a broader approach that transcends the study of human mobility. A theory on borders must be able to encompass and explain various types of cross-border flows, since a border’s functionality is not limited to just migratory management processes, though we should note that its various functions have a significant effect on its performance as a migratory filter (Fig. 3.1). Moreover, irregular or unauthorized migrations shape the exercise of border management, and it is where “migratory pressures” arise that innovative ways of implementing selective permeability mechanisms emerge. In addition, while different theories on migratory studies have had as their primary purpose that of explaining the directionality, volume, and composition of flows, border studies are focused on calibrating the specific effects that this type of filter has on mobility pathways and on the adaptive strategies of those involved in the movement, the migrants.

Fig. 3.1
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Mutual determination of borders and migration

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But how have borders been considered by the various social sciences? And what role is attributed to them in the realm of international migrations? As we will see in this brief review of the findings made by political science, sociology, geography, economy and anthropology, these disciplinary approaches may be viewed firstly as more complementary than exclusionary in their focus. Secondly, they exhibit different elements in the consideration of structure (macro) and agency (micro), as well in their emphasis in the selective and discriminating results of bordering.

A significant amount of recent theoretical output has come from political studies. In political sociology, political geography, and political economy, the main efforts have been directed at the goal of “bringing the state back in” to the analysis of migratory processes, concurrent with the entry into the academic agenda of ideas on cosmopolitanism, transnationalism, and the post-national and denationalization processes (Sassen 2007; Soysal 1994; Faist 2011; Hollifield and Wong 2014).

Political science and sociology have also focused their attention on analyzing the logic that defines and comprises the new migration control practices on an international scale (Lahav and Guiraudon 2006; Zolberg 2003; Cornelius et al. 2004) and their effects on territory and sovereignty (Balibar 2004; Mountz 2013). To these aspects, political geography also adds arguments regarding the emerging mobile character of borders both in terms of time and space (Anderson 1996; Pickering and Weber 2012; Bialasiewicz 2012). In political geography, borders are a socially constructed phenomenon and delimiters of social categories (Paasi 1996) which have been seen not only as signifiers of culture and identity but also as tools of exclusion and inclusion that create spatial compartmentalization and social difference (Newman 2006). These arguments are in agreement with those made by certain specialists in security studies, who maintain that borders have become complex and intricate technologies of control and government (Inda 2006; Pickering and Weber 2006; De Genova et al. 2015) responding to logics of securitization and criminalization of international irregular migration that legitimize extreme exclusion and destitution practices and create what has been defined as a permanent state of emergency and exception (Bigo 2006; Agamben 1998).

Borders have also been interpreted and rethought by economic sciences and regional studies. From an economic perspective, the border, as part of the international migration system, is an element that serves the interests of the state. Borders are seen as a type of barrier that, unlike natural barriers, constitute socially constructed norms (social institutions) that condition transaction costs, normally upward,Footnote 2 separate national economic systems, and allow for differences in each country’s internal operations. In short, the permeability and selectivity of borders depend on the state’s policies on the mobility of factors, be they goods (trade policy), capital (foreign investment policy), or people (migratory and mobility policy for travelers in general). Consequently, for economic theory, a retreat from a system of free exchange (free movement of factors on an international scale) means recognizing the importance of the political economy in determining the transaction costs between states and supranational entities.

Microeconomic theory and anthropology have distanced themselves from this state-centered interpretation of borders. In the former, they are one of the elements factored into the cost/benefit analysis of an individual’s or group’s decision to migrate (Stark 1991), as well as into the assessment of the risks associated with an unauthorized migration. In anthropology, borders are also negotiated spaces beyond the formal limits of the state (Donnan and Wilson 1998), defined by the collective narratives and experiences of the everyday practices of people living in borderland areas. In this sense, borders have been not only an important element in the study of human agency and human experience but also spaces of contact, exchange, and hybridism (Newman 2011). Hence, anthropology has focused part of its analysis on how migrants respond to and resist the migration controls exercised at a border and on their adaptive strategies for overcoming these restrictions by, for example, resorting to social networks and creating transnational social spaces.

All of these contributions, at once divergent and complementary, show how reflecting on borders and migration controls is able to produce an epistemological expansion of migration theory. In particular, based on the conception of a border as one of the “intermediate obstacles” (Lee 1966) that determines human mobility, borders are seen as a filtering mechanism where, via permeability and selection processes, many of the elements underscored by the various disciplines converge, primarily (a) the new spatial performativity of borders, (b) the tensions between agency and structure, and (c) the contradictions between the processes for facilitating and containing various immigrant profiles. Unlike the traditional approach of migration theory, which has attempted to explain the origin and continuity of migration flows, the analysis of migration control and border actions emphasizes the obstacles and restrictions to undesired mobility, opening a new field of inquiry that can benefit from a knowledge of migratory processes. In short, the intersection between border studies and migration theory offers an opportunity to observe the interaction between the macro (structure) and micro (agency) levels. It also underscores the need to resort to social theory to understand processes whose logic goes well beyond the geographic setting in which they occur.

3.2.2 Transformations of Migration Control Implementation: Borders as Permeability Control Devices

Borders, as mechanisms for managing the selective permeability between the interior and exterior of a social space, adapt in their implementation and management to changing geopolitical circumstances. In this sense, borders are dynamic, and their main challenge in the current context of globalization is to reconcile the agile screening of increasingly legal flows with the effective detection of unauthorized crossing attempts. In the case of irregular migration into the European Union, a significant percentage takes place at locations that are not equipped to handle border crossings, in particular maritime corridors. This is the main option for migrants with few financial resources who are forced to accept greater risks on these journeys (FRA 2013; Brian and Laczlo 2014).

Against this backdrop of Mediterranean maritime routes connecting the north of Africa with southern Europe, border management has evolved toward a situation that can best be described by the following attributes: (a) externalization, with outsourcing, remote control, and policing at a distance; (b) international cooperation and, in the case of the European Union, communitarization; and (c) technologization of the control, with the partial privatization of the technical innovation of security, and the adaptive response of migration strategies through the capitalization and technological sophistication of smugglers.

These tendencies are not exclusive to Europe; rather, they are notable examples of how rich countries seal their borders against irregular crossing attempts by poor and unqualified migrants. The goal of these restrictions to mobility is to have a dissuasive effect on the plans of potential migrants while they are still in their country of origin, hoping that the high likelihood of failure will result in many not even trying. Thus, effective border management is not measured exclusively by its effectiveness in frustrating crossing attempts (defined by a high probability of interception), because another goal is to indirectly disincentivize the choice of irregular migration as an individual or family strategy (which would be manifested by a lower influx at the border). Considering the huge migration potential from Africa to Europe, and given the notable differences in the standard of living on either side of the border, it appears that the goal of dissuasion is being achieved, at least in part, since the number of maritime interceptions continues to be relatively low in comparison to this migratory potential.

The three tendencies mentioned – externalization, communitarization, and technologization – are closely intertwined and mutually determined. Externalization implies the partial transfer of migration management to countries of origin or transit by way of a broad range of measures, the most important being visa policies and cooperation in police, military and intelligence matters involving the monitoring of departures, and migration transits. A good example of this is offered by the actions implemented in the wide interstitial maritime areas of the Mediterranean (López-Sala y Esteban 2010; Baldacchino 2014), where cooperation with countries in the north of Africa has proven highly effective at certain times and in specific contexts. Political instability in some of these coastal countries, however, shows how vulnerable this externalization policy is, as it depends on the wills and capabilities of other governments. In this sense, outsourcing migration controls to other countries and efforts at achieving “policing at a distance” require stable and firm political relations. They are also subject to constant negotiations in which transit countries can “play the migration card” as an additional resource to further their economic and political interests. For example, temporarily relaxing internal migration controls in these transit countries could be used to exert influence on stalled trade negotiations.

The second tendency, the communitarization of border controls (Godenau 2014), is an inevitable consequence of building the European Union as a single market with free movement that requires a common border in terms of permeability and selectivity conditions, both as regards trade and the mobility of people. As a result, it comes as no surprise that the European Union has endorsed initiatives that are gradually shifting the Union toward a shared border control, both through interstate cooperation and through the creation of organizations like FRONTEX. As concerns irregular maritime migrations in the Mediterranean, the EUROSURFootnote 3 initiative (European Commission 2008a; Jeandesboz 2011) is particularly telling. EUROSUR reflects the path toward the goal of the European Union’s Integrated Border ManagementFootnote 4 (IBM) by way of cooperation and joint control practices that rely on integrated information systems (Barbero 2012; Seiffarth 2012) and on coordinated surveillance through the network joint operations (NJO).

The third tendency, technologization, refers to the gradual incorporation of information and communications technologies – and of instruments based on these, such as satellites, drones, night-vision cameras, radars, and so on – into border control implementation. Technological innovation in this field is being driven by the European Union itself through its financing of applied research projects, typically led by companies with ties to the military and security industry (Godenau and López-Sala 2016). These technologies serve various functions in managing European borders, but they are particularly important to the migrant detection and interception phases. The subsequent identification and repatriation phases continue to rely to a greater extent on traditional technologies (passports, translators, means of transport, etc.). This increased reliance on technological means by expanding the land and maritime coverage of detection devices is triggering adaptive changes in the strategies employed by those organizing irregular border crossings. This technological race between border managers and irregular migration facilitators is fueling the growth of a migration industry that is becoming increasingly capitalized and technologized and that is encroaching on other areas of the military and security industry on the one hand and of illegal trade intermediaries (especially drug traffickers) on the other.

These three tendencies have resulted in the development of increasingly complex migration controls that, in an effort to contain flows, have had a notable effect not only on the likelihood that migrants will gain access to the territory of the destination country. They have also led to greater risks associated with irregular migration, risks that must be borne by the migrants. Hence, one of the most evident effects observed at some of the borders with the highest crossings is the drive, by both migrants and by national and international human rights groups, for new ways to respond to increasingly rigid controls. These new countermeasures have sparked a growing interest in the theoretical reflection on border control policies and on the configuration of restrictive migratory regimes (Nyers and Rygiel 2012) that violate the physical integrity of the migrants and cast doubt on the legitimacy of migration control.

This kind of public scrutiny of the praxis of migration control and the parallel construction of supervisory mechanisms around the forms that migration control has adopted is well covered by the concept of “humanitarian borders,” coined by Walters (2011). In Walters’s opinion, migration and border studies have extensively focused on analyzing the new rationales underlying the political measures and objectives of border control and on the securitization and technologization associated with them. However, an analysis that seeks to reflect the functional and symbolic transformation of the borders in the sphere of human mobility must also consider what Walters has referred to as the “birth of the humanitarian border” or the reinvention of borders as a space of humanitarian government and humanitarian engagement articulated through political struggles and the action of diverse agents which focus on a perspective of migrants as victims (de Genova et al. 2015).

3.3 Multilayered Deterrence of Irregular Maritime Migration in Spain

3.3.1 Context Embeddedness of Irregular Maritime Migration to Spain

Spain is part of the Mediterranean stage for irregular maritime migrations from Africa to Europe. Spain’s geographical position at the EU’s southwestern corner, and as a direct neighbor of Morocco, a 14.4-km journey across the Straits of Gibraltar, makes it one of the shortest potential and, in principle, least risky crossings.

The empirical pattern of irregular migrations from Africa to the European continent can be summarized in the following stylized facts: (a) pronounced variations in arrivals and interceptions, (b) dynamic changes in the pattern and dynamics of routes, (c) diversification in means of transport and in (d) migrant profiles, (e) expansion and capitalization of the smuggling “industry,” and (f) technologization of detection, interception, and diversion. We should add that migration flows from Africa to the European Union are relatively low in comparison to regular and irregular migration flows as a whole; nevertheless, they are the subject of attention from both the mass media and the public, hence the recurring idea of what has been called the “myth of invasion” (de Haas 2007). This volume is also low if compared to the migratory potential of a border with such a pronounced inequality as that separating the north and south Mediterranean coasts. The complex dynamic pattern of the Mediterranean setting is explained by the interaction between multiple factors that can in turn be assigned to several categories: (a) push-pull-type factors that generate a migration potential, (b) factors that condition the likelihood of opting for the irregular maritime option (depending on the relative appeal of other options), and (c) factors that affect the likelihood of being intercepted during the transit. Policies intended to seal borders have deterrent effects on all three categories, since deterrence affects migration plans (whether or not to migrate), the route selected and the mode of entry (the destination, the route, and the method), and the probability of success.

Statistical data provided by the European agency FRONTEX show a peak in maritime arrivals in 2013 and 2014, with particularly heavy traffic along the Mediterranean’s central and eastern routes (see Fig. 3.2). The growing use of these routes stems from the increasing political instability in countries along the south Mediterranean starting in 2011 and from the worsening Syrian conflict, which has resulted in a massive outflow of migrants and refugees. In parallel with these peaks, we see a change in the ethnicity of the migrants, with a growing presence of Syrians, Eritreans, Afghans, and Albanians, to the detriment of sub-Saharan migrants. As the frequent sinkings demonstrate, migrants along these routes have had to assume greater risks, due mostly to the longer maritime distances involved and to overloaded vessels.

Fig. 3.2
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Illegal border crossing by route (Source: European Commission 2015)

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As a consequence of these recent changes, Spain has lost importance in terms of its share in the number of irregular migrants arriving via maritime routes along the European Union’s southern border over recent years. The current situation is the result of a change over time that has gone through several phases: the first, from the 1990s until 2000, in which the western Mediterranean route prevailed; the second, from 2001 to 2008, with the intense growth and subsequent collapse of the west African route via the Canary Islands (Domínguez-Mujica et al. 2014); and the third, starting in 2008, when the Mediterranean route regained its importance. It is possible that the current situation will undergo changes and, as FRONTEX notes, “several indicators point to a continued increase in migration along this route” (FRONTEX 2014, p. 6). The cities of Ceuta and Melilla comprise a particular case in the scenario of migration routes for irregular crossings into Spain. Their growing prominence in recent times as a land crossing is explained by the fact that “they do not require the costly involvement of a facilitation network” (FRONTEX 2014, p. 19), such as that associated with maritime crossings.

Despite the gradual construction of a common migration control policy in the European Union, the states receiving these migrants continue to retain a high degree of autonomy and intervention through national and bilateral initiatives involving the design and implementation of their migration policies. In this regard, the EU’s policy complements national policies in the sense that states enjoy ample maneuvering room while providing the wealth of knowledge and experience that serves to underpin much of the common policy. Italy’s recent experience along the Mediterranean’s central corridor, as well as Spain’s experience in the middle of the last decade, show the limitations and partiality of European initiatives to engage in effective control during times of intense migration flows. In the context of the migratory setting of the Mediterranean, Spain’s strategy has evolved by following a progressive and comprehensive multilayered deterrence strategy along three main areas of action: (a) a gradual externalization and geographical extension of border control, (b) intensified bilateral and multilateral cooperation with the African countries involved, and (c) the gradual Europeanization or communitarization of actions aimed at integrated border management.

3.3.2 Tendencies in Border Management in Spain

The migration control exerted by Spain along its southern maritime and land border exhibits the three tendencies mentioned earlier. It also involves a multilayered deterrence strategy intended to control irregular immigration. The last decade saw the intensification of bilateral and multilateral initiatives with those African countries where these flows originate and transit through. These initiatives have been shaped and have served to reorient Spain’s foreign actions, particularly those involving Morocco, Mauritania, and Senegal. This cooperation has included surveillance and detection activities both on land and along the coasts of transit countries and collaboration in monitoring maritime routes for the purposes of early detection, identification, and return (López-Sala 2015). These types of deterrent measures, implemented through various policy instruments for external action, such as migration cooperation plans like the Africa PlanFootnote 5 or bilateral readmission and repatriation agreements (Asín 2008), have been combined with other security policy instruments relative to intelligence and risk detection. The best example of such a dual bilateral action combining external action and intelligence was the creation of what is known as the Atlantic Seahorse Programme and the Sea Horse Network.Footnote 6 This active bilateralism and its containment effects in Spain’s case have had an important influence on Europe’s still developing migration policy for its maritime borders and the partial communitarization of this policy. The high influx of irregular immigration in Spain in the years following the creation of this policy transformed Spain’s border into a geographic testing ground for many of the initiatives developed later along the common maritime border. After the creation of the European border agency (FRONTEX), the Hera, Indalo, and Minerva joint operations became the first initiatives to supplement the joint surveillance being carried out by Spain and other countries along maritime routes to Europe.

The migration control strategy has not only relied on resorting to policy and intelligence instruments but on the use of new technological strategies and capabilities. The technologization of migration control has developed along two lines: on the one hand, the employment of detention and barrier technology in parallel with the use of long-distance and remote control technology and, on the other, the progressive search for collaboration in technological innovation both between countries and between the public and private sectors.

Lastly we should note that the application of these border control initiatives has had various effects on the dynamic of migration flows. Evident are the so-called deviation effects, in reference to the appearance of alternative routes or to the intensification of existing routes. Also noticeable are selective effects involving the strategies adopted by migrants as a function of their financial capabilities and their social and relational capital. This includes new access mechanisms, such as the growing use of new illicit crossing techniques (including the use of false documents) or, as in the case of Ceuta and Melilla, a transition from a trickle influx to a strategy involving waves of immigrants attempting to cross the land perimeter.

The gradual impermeabilization of Spain’s external border in recent times has led to a heightened social debate on the effects of this policy and especially on the controls used in Ceuta and Melilla. There are three elements of social debate articulated by the opposition to the actions of the current Spanish government: first, the use of containment equipment at border perimeters, in particular the use of concertina wire; second, pushback deportations criticized as irregular return practices; and third, the lack of guarantees in the international protection processes for potential asylum applicants at these land borders. The two most important elements in response to these actions have been the breadth of the social agents involved, which include not only human rights organizations but also legal associations, police organizations, and Spain’s own Ombudsman and, secondly, how this response and its associated advocacy practices have been deployed using multiple strategies, including visibility in the media, political influence, and appeals to courts and to European institutions.

3.4 Final Remarks on the Intersection of Migration and Borders: Feeding Back Empirical Patterns into Theoretical Considerations

Borders are state-driven permeability control devices; they are rules with enforcement costs and these depend on entry (or exit) pressures (Godenau 2012). As mechanisms of selective permeability, borders conform to the state’s logic, which is based on understanding and characterizing certain migratory flows as desired or undesired. In today’s receiving societies, this logic is characterized by facilitating the former and containing the latter.

Over the last decade, migration and border control measures have been implemented as part of a multilayered and multisited deterrence strategy that includes both physical containment actions and other, indirect means of dissuasion (Godenau and López-Sala 2016). Migration control through border management is possible and real. Although overgeneralized statements about the ineffectiveness of borders abound in the media and international reports (as evidenced by sentences such as “people vote with their feet,” “nothing can detain the force of desperate humans,” “higher walls bring longer ladders,” “it’s like squeezing a balloon”), we think EU and Spanish bordering demonstrates deterrence can be achieved, but normally at the expense of other destinations (deviation effects in migration routes and entry strategies) and of migrants themselves (higher risks and higher costs for trespassing). This is why the assessment of migration control measures is tied to the concepts of effectiveness and efficiency. It is worth nothing that effectiveness and efficiency are different concepts: the first involves achieving a goal, and the second includes cost (effort) optimization in achieving this goal.

Effective deterrence implies an increase in border transaction costs (not to be conflated with border implementation costs) and creates transborder opportunity structures for agents who specialize in permeability/impermeability maintenance. Migration “industries” are just one more example of how these opportunity structures manifest themselves in irregular border crossing (irregular trade, smuggling, is another example). Due to the spatial dimension of borders, these industries flourish in border regions (and both sides of the border) (Gammeltoft-Hansen and Sorensen 2013). As trespassers attempt to thwart or bypass border controls, this may provoke increasing costs for all participants: migration industries capitalize through innovation (including transport technology, communication devices, fake documents, etc.), and border implementation technology reacts to these new “threats and risks” (using the Frontex jargon). As a consequence, migration industries tend to diversify in both the horizontal (more functions) and vertical directions (e.g., integration into multinational drug trafficking organizations).

Though all technology is of an instrumental nature, the design and use of technology is not socially and politically neutral. A large amount of public and private resources is used to create and implement border technology. The EU’s Integrated Border Management, progressively expanded in different levels and countries, is used to selectively screen mobility. Ideally desired legal mobility is to be promoted and unhindered by border controls, while illegal and undesired flows should be detected as early as possible and effectively avoided without interfering with regular mobility. As most immigration policies try to maximize the economic contribution of migrants to their countries, and poor and less qualified migrants are seen as a burden, these profiles of socially desired migrants are reflected in bordering through their counterpart: border technology tends to detect poor irregular migrants on their routes. This construction of migrant categories is therefore a logical consequence of the social filtering functions of borders.

In terms of migration theory, deterrence is related to intermediate obstacles (Lee 1966) and directly (and negatively) influences real immigration and immigration intentions through interception (related to theories on accumulative causation in international migration: bordering stops migration from taking place) and indirectly through its influence on migration projects (related to theories on why migration starts). As a result, the emphasis in migration control studies on analyzing the obstacles and restrictions to undesired mobility allows for the incorporation of a new approach that could enhance migration theory by offering alternative explanations of why migration is contained or stopped, thus explaining the phenomenon of immobility.

Agency and structures interact in bordering and migration control practices. Borders are social institutions, and as such they are designed and implemented with the aim of channeling individual and group behavior. Agency responds adaptively to these structural constraints, using, in the case of migrants, forms of relational capital and community support networks. Through their actions, they cause a certain degree of institutional change, with the larger part of these changes normally being due to preventive and adaptive state (and supranational) action. The state is not to be seen as only relevant as a macrostructural element, because the state also is a stakeholder and appears through its action at the border as such. Although the observation of specific border sites can be labeled as microanalysis, we should be aware of the presence of both micro and macro dimensions in every social reality. The humanitarian border concept illustrates that the interaction at the border also includes civil observers and organizations. The social response to certain bordering practices shows how microscale evidence is channeled through the meso-level (organizations) up to the macroscale (immigration policy). What does this imply for migration theory? It means we need theories that can flexibly integrate both downscale (structural conditions channel action) and upscale (agency induces institutional change) processes.

Borders are useful “places” for bringing (back) space into social (migration) theory. The social construction of space is clearly visible at conflictive and contested borders. Research on these locations offers an opportunity to improve social theory in its spatial dimension. These locations are not only placed at the external geographical perimeter of states, but they are also to be found inside these countries, in other countries’ territories, and even in international/trans-boundary waters and high seas. Migration theory is also bound to include spatial considerations, as migrants are physical objects moving in space, which is why borders have to be physical at some point in time and space. This physical trait of both migration and borders is relevant to social theory in several aspects: (a) borders as implementation sites (a laboratory for observing agency-structure interaction); (b) borders as social barriers and delimiters of social categories; (c) border areas under migratory pressures as places in a constant state of emergency and exception (social discourse), including the implementation of forms of spatial exceptionalism and spatial excision; and (d) the social construction of social fields bridging borders (migratory transnationalism in border regions).