1 Mobilities in the historical development of international law

The common doctrinal narrative of the role of human mobility in international law would begin with the formalisation of migration pathways in the twentieth and twenty-first centuries through the international minimum standard of treatment for aliens, and the emergence of international refugee law and human rights of migrants, as the legal paradigm for conceiving the movement of persons across state borders (e.g. Chetail Reference Chetail2019; Opeskin, Perruchoud and Redpath-Cross Reference Opeskin, Perruchoud and Redpath-Cross2012). While this narrative is certainly valid in terms of describing the legal origins of a large part of what we now call international migration law (IML), it remains attached to territorialist assumptions and a static ontology that tends to neglect the characteristics of human sociality as essentially mobile.

A more revisionist history is now casting new light on this dominant legal narrative from two main angles. First, a growing number of scholars have come to recognise the colonial roots of IML. For example, Vitoria’s right to communication between peoples ostensibly provided for freedom of movement but also served to justify colonial expansions through Spanish conquest (Chetail Reference Chetail2016). For Vitoria, this ius communicatios was not limited to a right to travel and corresponding duties of the receiving state to provide hospitality; is also included free trade and navigation and ius soli (Chetail Reference Chetail2016). Based on an opening reference to Virgil’s portrayal of the shipwrecked refugee Aeneas, Grotius similarly expanded mobility rights based on the principle of hospitality, from which he inferred the rights of innocent passage and freedom of the high seas, and further articulated rights to leave and a right to remain in a country (Gammeltoft-Hansen Reference Gammeltoft-Hansen2017). On the one hand, these were seemingly liberal endeavours; on the other, they aided Dutch colonial profiteering (Tuck Reference Tuck1999, pp. 78–108).

Second, some scholars have come to emphasise that freedom of movement is not just a modern corollary of regional trade regimes, but a persistent feature – and what makes history ‘human’ (e.g. Manning Reference Manning2012). This is evident from the earliest movements from Africa, but became patently clear as migration dramatically increased with the development of technologies necessary to traverse bodies of water (Bhabha Reference Bhabha2017). This has led legal scholars to argue that contemporary restrictions on international movement may be more of a historical aberration rather than the norm (Juss Reference Juss2004). Similarly, the sovereign right to exclude aliens – which is often regarded as stemming from the writings of Vattel, Pufendorf and Wolff – has been shown to be more a product of judicial reiteration in the twentieth century informed by racialist premises, rather than representing any firm basis in early modern customary international law (Nafziger Reference Nafziger1983; de Vries and Spijkerboer Reference de Vries and Spijkerboer2021).

From different angles, then, human mobility has been central to the development of international law. Yet, this literature largely presumes that the role of law in generating mobility is largely epiphenomenal. This narrative further imbues contemporary accounts of international migration law, which is often described as a ‘deconstructivist design’ (Chetail Reference Chetail2017) or a ‘giant unassembled juridical jigsaw puzzle’ (Lillich Reference Lillich1984). As the institutional framework for migration has proliferated across international and regional legal regimes, some scholars have predicted the rise of regime complexity (Betts and Kainz Reference Betts and Kainz2017) or legal fragmentation (Chetail Reference Chetail2017; Wilde Reference Wilde2017) yet these arguments continue to take the premise that the normal state of law is fixed and not in transient form, that law responds to mobility rather than being ontologically bound to it.

Perhaps a better way to approach the problem is to conceive of human migration as but one species of mobility in light of its historically transformative role in shaping what we now think of as our globe. This is no sleight of hand but the core of our research problem: international legal scholars know a lot about how law operates when people leave from or arrive at another country, but much less about how it operates while persons are mobile. The legally cognisable ‘migration circle’ is thus often described as ‘departure from the country of origin; admission into the territory of the destination State and sojourn therein’ (Chetail Reference Chetail, Chetail and Bauloz2014). However, empirical evidence has shown that the vast majority of mobility takes place at nearby distances (Deutschmann and Recchi Reference Deutschmann, Recchi, Recchi and Safi2024), and that among people on the move, only a small minority are migrants as traditionally defined – understood as a person who has changed their country of residence (e.g. Caron Reference Caron, Recchi and Safi2024). What is required is an epistemic reorientation that takes into account the difference between migration as a legal category, pertaining to persons who cross borders and reside regularly or irregularly for a certain period of time and the quality of mobility itself, which denotes an essential aspect of movement – a state of being mobile.

As a concept, mobility captures a world that is in constant flux with regard to people and identities but also ideas, goods and (in)tangible objects. As a point of distinguishing transient form, it also requires that some things will remain immobile. Mobility is thus not just about movement; it is about meanings: ‘mobility can do little on its own until it is materialised through people, objects, words, and other embodied forms’ (Salazar Reference Salazar, Salazar and Jayaram2016). From this point, it is not too difficult to see how mobility is key to social structuring. It is ‘a relationship through which the world is lived and understood’ (Adey Reference Adey2010). Mobility tends to be associated with globalisation discourses on the presumption that there is now more of it and that this should be valued as improving human lives. Yet, scholars have persuasively shown how ‘mobility’ – and crucially, the regulation of its forms – is neither a cause nor by-product of globalisation, but rather a central aspect of modernity (Cresswell Reference Cresswell2006). In feudal societies both landowners and serfs were tied to the land and those who were not were exiles. In the early modern period, commercial mobilities de-rooted feudalism and called for new techniques of surveillance and ‘the poor’ to be managed through a developing idea of national welfare (see further Sassen, Reference Sassen2008).

Mobility, moreover, was central to the birth of the modern nation-state as a political entity which exercises moral authority over a territorially bounded class of persons. This was not just a material transformation but also reflected in the political philosophies of the time. Hobbes borrowed from Galileo’s notion that movement was the natural state to articulate his idea of mobility as being at the heart of individual freedom (Cresswell Reference Cresswell2006). Moving from the state of nature thus entailed not only state monopolisation of violence but also legitimate movement as an essential aspect of the transition from feudalism to capitalism (Torpey Reference Torpey2002). This in turn required a new ideology of mobility with the idea of citizens being granted the right to move within a state, subsequently exported in colonial distinction between ‘citizens’, who held political rights, and the colonised, who were only considered ‘nationals’ (Kmak Reference Kmak2024). Mobility thus went hand in hand with liberalism in creating the ‘ordered movement’ and ‘ordered freedom’ of imperialist extensions of the state that were categorically granted to some persons but restricted for others (Kotef Reference Kotef2015).

Far from just a historical contingency, mobility moreover continues to play a powerful role in constituting what we think of as state sovereignty today. Writing in the vein of law and geography, scholars have demonstrated how sovereignty is constantly contested or even redefined by mobile populations (Everuss Reference Everuss and Elliott2020a), such as in the case of Australia’s excision of offshore territories, to categorically exclude asylum seekers who arrive by boat from protection obligations (Mountz Reference Mountz2011). Others have argued that sovereignty is a ‘zombie category’, a social institution that is sustained through ongoing generative performances of inclusion and exclusion (Everuss Reference Everuss2020b). Attenuations to sovereignty may also arise through ‘state mobilities’ exercised by the state itself as a mobile actor (Mountz Reference Mountz2011), through mechanisms such as ‘shifting borders’ (Shachar Reference Shachar2020), simultaneously restricting and liberalising sovereign space across multiple sites of governance (Dickson Reference Dickson2015; Everuss Reference Everuss and Elliott2020a). Even beyond claims to state territory, international law facilitates shifts to sovereignty through, for example, means of migration control, detention or controlling populations through the exploitation of ‘legal black holes’ across different levels of materiality, such as land, air and sea (Peters Reference Peters2014; Wilde Reference Wilde, Sheeran and Rodley2013; Mann 2018).

What this literature points to is the powerful capacity for mobility to constitute international law – not only by shaping its doctrine, but also making up its material building blocks. However, a large part of this scholarship, in working within a legal paradigm frames law as merely responsive to the social, political and economic forces that undergird human movements. Vice-versa, research from mobilities theory tends to approach law as relatively homogenised, inseparable from entities such as the citizen and the nation-state, rather than as a powerful driving force of mobility, with its own impetus and trajectories, in all of its granularity and in its own right. In the next part, we thus explore the further purchase of mobilities theory for analysing the power of law to map a globe by controlling movements around the world.

2 The role of law in shaping human mobilities

International law provides a vocabulary to order this world (Koskenniemi Reference Koskenniemi2021), but its world-making practices also encapsulate human sociality and values (Mansouri Reference Mansouri2022). It enables cognitive categories which help us to sort configurations of norms and practices as a constituted juridical reality (Uruena Reference Uruena2024) including for how we, as humans, experience mobility. The law pertaining to persons who move across borders spans a broad set of legal regimes. It comprises what might be thought of as a ‘general part’ arising from customary international law standards for the treatment of aliens and the protections of international human rights law (Cf. Gammeltoft-Hansen and Madsen Reference Gammeltoft-Hansen and Madsen2021) but also a range of specialised areas of international law covering specific classes of mobile populations – for example, transnational labour law, refugee law, international criminal law, diplomatic law, the law of the sea (Gammeltoft-Hansen Reference Gammeltoft-Hansen, Moreno-Lax and Papastavridis2016) and international trade law (Panizzon Reference Panizzon2011). Mobility law provisions can further be found in legal regimes which are largely universalised as facilitating international co-operation, such as international aviation law (e.g. Huremagić and Kainz Reference Huremagić and Kainz2020) and international health law (Ó Cuinn and Switzer Reference Ó Cuinn and Switzer2019). One could add the vast body of regional and sub-regional laws for mobility, such as the ECOWAS, EU, MERCOSUR and Andean Community free movement agreements (Acosta Reference Acosta2018).

Yet from a doctrinal legal perspective, there currently remains no overarching normative framework for mobility law. In its absence, we lack a clear understanding of how its different elements interact and shape mobility patterns. Calls to expand legal research have underscored the importance of cross-sector approaches that look to the intersections of legal frameworks (Costello and Mann Reference Costello and Mann2020), as well as engaging multidimensional perspectives on the transnational movement of persons (Ramji-Nogales and Spiro Reference Ramji-Nogales and Spiro2017) and interdisciplinary analysis of the evolution of the migration regime outside of formal processes (Janmyr Reference Janmyr2021). Other scholars propose that research on migration law needs to abandon state-centric paradigms by re-imagining ‘a global system of human mobility’ that puts humanity at the forefront (Aleinikoff Reference Aleinikoff2017). The majority of this literature, however, is directed towards expanding existing trajectories in migration law research, rather than approaching law as constituting human mobility more broadly.

This paramount purchase of the mobilities turn in the social sciences emerges at this point in helping to foreground the multi-faceted nature of mobility, as well as the socio-material dynamics that underpin it. Mobilities theory has antecedents in the spatial turn in the social sciences and its vision of space as a social construction (Lefebvre Reference Lefebvre and Nicholson-Smith1991; see also, in international legal scholarship, Lythgoe Reference Lythgoe2024), as well as descriptions of the socially constitutive linkages of relation in ‘network society’ (Castells Reference Castells2011) and the characteristics of ‘liquid modernity’ where social meaning arises transnationally (Bauman Reference Bauman2000). As such, mobilities theory calls for a ‘sociology beyond societies’ (Urry Reference Urry2000), which entails a departure from the idea that ‘society’ is fixed to geographically contained units. Yet it also challenges narratives of the decline of space as a scheme of social organisation, with the posit that social meanings are always contingently re-formed through mobile pathways – whether they encompass persons, goods, information or ideas and notions (Sheller and Urry Reference Sheller and Urry2006).

Mobilities theory is an eclectic body of research, but it unites around a foundational paradigm of a ‘mobile ontology’ that presupposes that ‘movement is primary as a foundational condition of being, space, subjects, and power’ (Everuss Reference Everuss and Elliott2020a; see also Nail Reference Nail2015, Reference Nail2018). This shifts analytical attention away from static concepts such as state and society and towards ‘resonances, connections, continuities, and disruptions that organise the world into ongoing yet temporary mobile formations’ where mobilities are ‘located and materialised’ or linked with ‘moorings’ (Sheller and Urry Reference Sheller and Urry2006; Hannam, Sheller and Urry Reference Hannam, Sheller and Urry2006). Mobilities are typically taken as comprising material, symbolic and practical elements, and often described as assemblages where agency is distributed between humans and non-humans (Büscher and Urry Reference Büscher and Urry2009; and further Latour Reference Latour2002), or as complex systems (Hannam et al. Reference Hannam, Sheller and Urry2006). When perceived as an assemblage, mobile relations are typically taken to exhibit network-type effects, and when analysed as complex systems, mobilities are ‘simultaneously economic, physical, technological, political and social’ (Everuss Reference Everuss and Elliott2020a). Mobilities theory is a critical agenda, and thus while everything in theory is mobile, mobilities theory tends to focus on the contingently mobile. Its proponents adopt different registers for locating critique, from relational studies (Adey Reference Adey2006) to more hierarchical studies of, for example, biopolitics (Sheller Reference Sheller2016).

Thus far, however, law has remained largely absent from these discussions. Mobilities scholars from other disciplines tend to view law as a background variable and largely static factor in human mobility, and the bureaucracy of ‘regulation’ as something that must be worked around (e.g. Xiang and Lindquist Reference Xiang and Lindquist2014). Within socio-legal scholarship, it has been argued that law is mobile insofar as transnational communities appropriate and frame it within new settings (von Benda Beckmann et al. Reference von Benda Beckmann, von Benda Beckmann and Griffiths2005). Working from the tradition of jurisprudence, others have shown how legal movement is technical and material, and constantly reproduced through ‘place making activities’ such as colonial projects (Barr Reference Barr and Philippopoulos-Mihalopoulos2019). Most recently, Kmak (Reference Kmak2024) has persuasively elucidated how mobility provides a constitutive force for social systems and thereby renders forms of stability as political power. Yet, each of these analyses tends to neglect the role of law in shaping mobilities and the recursive relations between law and mobility that arise through this dynamic relationship.

In the following, we seek to move from these analyses to outline how, on the one hand, international law not only plays a much more prominent role in shaping global mobilities and, on the other, how adopting a mobile ontology enables novel insights for legal analysis. We do so by employing two paradigmatic examples from existing social science studies on human mobility. First, the classic sociological protagonist of the tourist – here highlighting the intricate but also highly bifurcated legal infrastructure for global leisure travel. Second, the more recent COVID-19 pandemic and its cataclysmic legal effects for global mobility – here pointing to the intimate relations between human and non-human elements in mobility cycles.

3 The global tourism infrastructure

Within mobilities theory, as well as sociology on globalisation more generally, the tourist arguably remains the quintessential mobile subject of ‘liquid modernity’ through their ability to move throughout the globe at high speed, transcending social systems and cultures. (Bauman Reference Bauman1996, Reference Bauman2000; McCabe Reference McCabe and Adey2014; Sheller Reference Sheller2004) The mobility of tourists is exemplary of the operation of the ‘mobility infrastructure’ that links geographies through socio-technical systems which manage people’s physical movements both over long distances and in their daily routines, and at least partially by redistributing mobility between types of movement and populations (Xiang Reference Xiang2024). Just as roads enable transport for cars, railways link towns and cities, airports link centres and peripheries spread across regions. Each scale of mobility is comprised of a technical element, a physical infrastructure that moves and sorts mobilities, but also practices that enact sociality and norms, such as ‘drive on the left’, and symbols to stop and go. To draw an analogy from Latour (Reference Latour1990), this is a socio-technical platform; a pilot does not fly, ‘(f)lying is a property of the whole association of entities that includes airports and planes, launch pads and ticket counters.’ Similarly, it is not tourists that travel, but constellations of humans and socio-technical platforms – enabling, for example, a cruise ship to operate as ‘floating cities’ (Gammeltoft-Hansen and Mann Reference Gammeltoft-Hansen and Mann2024; for a similar argument see Xiang and Lindquist Reference Xiang and Lindquist2014). From this angle, it becomes clear that ‘(t)he question of how people are moved is at least as important as the question of how people move’ (Xiang Reference Xiang2024) as mobility infrastructures play a crucial role in ‘categorising moments in production’ (Lin et al. Reference Lin2017).

The global visa regime, as an enormous scheme of regional and bilateral treaty arrangements, provides a glaring example of the constitutive role of law in terms of accelerating travel for persons from the Global North and de-accelerating it for persons from the Global South (Spijkerboer Reference Spijkerboer2018). However, nationality – and hence geography – is not the only dividing line in this regard. Many visa waiver programmes are moreover class-based in exempting specific categories of travellers, such as diplomats, business travellers and/or government officials. For travellers who do need to obtain a visa, personal net worth, social position and education are often key assessment criteria (Infantino Reference Infantino2019). In this way, the visa as a legal device effectively reveals the patterns of discretion and arbitrariness enabled by law to control mobilities on a local scale, but with consequential effects in mapping a mobile globe. The visa is not just a stamp in the passport; rather, it is a whole host of interlocking logics – from private intermediaries to various forms of policing – that provide a ‘constant assertion of power over moving bodies’ (Megret Reference Mégret2024).

The experience of the visa regime thus suggests that the international tourism infrastructure operates quite differently from the liberal narrative espoused by, for example, the UN World Tourism Organization for ‘bringing the world closer’ (UN Reference Uruena2024). The Global Passport Index (Passport Index 2024) is another way to gauge this global disjunction. Each year, it ranks national passports by ease of restriction, and thereby paints a stark picture of a virtual visa apartheid between the Global North and South (Mau et al. Reference Mau2015). From this perspective, the tourist infrastructure can be seen as emblematic of a ‘racialized border’, one that ‘privileges “whiteness” in international mobility and migration’ through supposedly neutral legal categories, such as a ‘right to leave’ one’s country of origin (Achiume, Reference Achiume2023). The material aspects of tourism infrastructures, such as aeroplanes, boats and roads further interlock with a whole host of international and national laws that enable and constrain movement of persons around the globe. Law, in other words, plays an integral role in facilitating and conditioning global tourist mobility through a physical and ideational infrastructure.

Borders remain the most obvious manifestation of the materiality of this infrastructure, and the legal construction of the border as a site of material and symbolic violence has been subject of extensive scholarship (e.g. Dijestelbloem Reference Dijestelbloem2021; van den Meerssche, 2022). However, legal studies in this area tend to focus exclusively on legal sources pertaining to and mobilities to the Global North; a reflection of the wider epistemic bias in migration law scholarship (Spijkerboer Reference Spijkerboer and Dauvergne2021; Chimni Reference Chimni1988). A different narrative of the global visa regime could recognise the role of law in the recursive (re)generation of mobilities, as restrictive visa policies in the Global North has also been accompanied by visa reconfigurations in African and South America regional blocs (Czaika et al. Reference Czaika, de Haas and Villares-Varela2018). These flow-on effects are not always positive. As part of so-called externalisation policies, the EU and its member states have entered into mobility partnerships in several regions, whereby third states are encouraged to more closely control secondary movements and impose national border controls in an exchange for development assistance (Byrne and Gammeltoft-Hansen Reference Byrne and Gammeltoft-Hansen2024). The price for regional free movement in the Global North is thus undercutting those very same freedoms and regional mobility arrangements in other parts of the world.

Similarly, when we think of global mobility, our imagination is often drawn to the hyper-mobile. International aviation is emblematic in this regard, encapsulating the supposed virtues of human mobility in connecting human lives for social connection, leisure and commerce. While the facilitation of international aviation through visa laws enables international tourism, the wealthiest 10 per cent (and among the world’s most mobile) consume a disproportionately large share of fossil fuels and thereby contribute to the generation of ‘climate mobilities’, which in turn are causing livelihood depletions in other parts of the world through their ‘high-energy life-styles’ (Sheller Reference Sheller2020; Boas et al. Reference Boas2022). Tourists have furthermore long moved through other routes that operate through their own vicious logics. The fastest-growing form of international tourism, cruise ships, were originally branded as the world’s first single-class form of travel, and owes much of its success to its hyper-mobile constitution – breaking with fixed routes and destinations in favour of making mobility the destination in and of itself. Yet, from a legal perspective, the cruise ship navigates a complex web of laws: on the one hand, drawing from colonial structures of freedom of navigation to late-sovereigntist constructs such as open registries; and on the other, relying on private law protections and trans-regional networks of limited liability waiver contracts for both passengers and crews. Far from the egalitarian consumer narratives of bringing affordable luxury to the masses, the cruise ship itself thus emerges as an example of a compressed global value chain, replete with sweatshop conditions of labour below deck and negative externalities in the form of excessive and largely unregulated aerosol and maritime pollutants (Gammeltoft-Hansen and Mann Reference Gammeltoft-Hansen and Mann2024). The spectacle and performance of tourism (McCabe Reference McCabe and Adey2014) thereby elides the foundational role of law in enabling class-based injustices and causing damage to the natural environment.

In sum, these examples show the powerful control that law exerts over mobilities by defining space through ‘deeply spatialized theoretical categories’ such as jurisdiction that cast a legal imagination on ‘a portion of the surface of the globe’ (Lythgoe Reference Lythgoe2022). However, law is also performed in places such as border zones by actors such as immigration control (Rajkovic et al. Reference Rajkovic, Aalberts and Gammeltoft-Hansen2016), and these sites can spatially extend beyond geographies through practices (Walters Reference Walters2022), are enacted through materialities such as the passport (Lloyd Reference Lllyod2003) and carried around the world through sociotechnical objects, such as aviation and cruise ships (Salter Reference Salter2007; Gammeltoft-Hansen and Mann Reference Gammeltoft-Hansen and Mann2024). In this way, mobility functions through a dense infrastructure that extends the normative reach of law to a globe of corporeal control over movements, as we always carry our mobility markers – such as nationality, class and race, and thus jurisdictional status – in our bodies (Merlaeu-Ponty Reference Merlaeu-Ponty1945; Sheller Reference Sheller2018; Kmak Reference Kmak2024). In the next part, we will further explore how law travels through mobile pathways through an exposition of the role of international law in the COVID-19 pandemic.

4 Global mobility and the virus

In the previous part, we sought to show how the way in which we experience the world-making power of mobility may be radically different depending on its actualisation in place and space; that is, law provides the ‘circumference’ for being mobile (Burke Reference Burke1945). This world of interconnected mobilities and immobilities experienced significant disruption from 2020 onwards with the COVID-19 pandemic – itself a highly mobile virus that affected humans and non-humans alike, and spread transnationally through traditional vehicles of mobility such as tourism and transportation networks.

The negative impacts of the COVID-19 pandemic on the transnational movement of people, goods, services and capital are well known. The virus spread from a market in Wuhan to a ski resort in Ischgl, was subsequently transported from buses to Innsbruck airport, and thereafter exported as tourists returned to their homes throughout the globe (Oltermann and Hoyal Reference Oltermann and Hoyal2020). In the shutdowns enacted from March 2020, much human mobility immediately came to a halt; airline traffic dropped by more than 70 per cent, cruise ships were locked out at sea, transient forms of labour migration declined, and foreign nationals were trapped – often with little aid from their host or home governments (Achiume et al. Reference Achiume, Gammeltoft-Hansen and Spijkerboer2020). However, the ‘global mobility apartheid’ which separates the world through legal devices did not cease or become levelled out – despite the fact that infection numbers were much higher in the hyper-mobile Global North during early parts of the pandemic. Rather, it was exchanged for a ‘fluctuating sanitary apartheid’ (Heller, Reference Heller2021), shifting existing restrictions on mobility between states downwards along socio-material divides within states and local communities (Ogg and Simić, Reference Ogg and Simić2022), and introducing new socio-legal devices that enabled limited mobility for some, but not for others.

The first narrative of the COVID-19 pandemic, in respect of the role of law in mobilities, is one of infrastructural breakdown – an event that brought the character of its operations into full scope (Star Reference Star1999; Bowker and Star Reference Bowker and Star1999) by causing ‘a vast intensification of existing uneven relations of (im)mobilities’ (Adey et al. Reference Adey2021). The most immediate manifestation were world-wide border closures, which heightened already strained relations in many parts of the world, otherwise accustomed to bilateral or regional freedom of movement in areas such as the Schengen zone (Byrne and Gammeltoft-Hansen Reference Byrne and Gammeltoft-Hansen2024). It also led to a host of legal challenges from expatriate citizens whose states of nationality either prevented or failed to sufficiently assist them from coming home (Simic Reference Simic2021), and it further stratified existing social and class-based inequalities. The introduction of ‘COVID-19 passports’ is a notable example in this regard, as it made admission contingent on being in possession of a valid virus test (Dehm and Loughnan Reference Dehm and Loughnan2022) with a pronounced detrimental impact for citizens in countries where access to testing was more difficult, or for groups already disenfranchised from access to national healthcare such as irregular migrants (Lang and Ramji-Nogales Reference Lang and Ramji-Nogales2020).

The second narrative of the COVID-19 pandemic’s impact on mobility is much less well known but equally informative. It highlights how legal measures in relation to mobility rarely, if ever, have one-sided or foreseeable effects. As borders shut, the pandemic sparked what is quite possibly the largest human return migration in modern history (Guadagno Reference Guadagno2020). Across the globe, lockdowns led to mass reverse migration of persons such as students, seasonal workers, precarious labour migrants and even many long-term expats – each deciding to return due to a combination of different factors, whether the loss of opportunities ensuing from the lockdowns, the importance of social networks in the home country or because of the protective ambit enabled by the legal device of citizenship. The exact scope of this return migration is difficult to quantify. One of the most well-documented examples concerns the tens of millions of urban workers in India returning to their rural regions of origin, many of whom suffered significant discrimination on the ‘long walk home’ (Misra Reference Misra2022). In some cases, governments forcibly repatriated migrant workers, such as the Iranian government’s expulsion of some 850,000 Afghans. In others, states adopted novel measures for containing their nationals within the home state, such as the Philippines’ ban on the emigration of nurses, and repatriating its own citizens from abroad (Xiang Reference Xiang2020). Thus, while the majority of COVID-19 measures were intended to stymie population mobility, the lockdowns also created new patterns of large-scale mobility.

At a second level, the pandemic and the ensuing return migration highlight the Global North’s fundamental dependency on mobility in the form of a steady supply of migrant labour and a transnational service industry. Across Western countries, COVID-19 immobilities coincided with supply shocks, many of which continue to reverberate today – for example, in the form of significant labour shortages across many key industries. COVID-19, in this sense, represents a case of ‘shock mobility’ in the sense that not only the pandemic itself, but also governmental efforts to legally regulate it, significantly altered the ‘speed, directions, meanings, and consequences of existing mobilities’, with a particular impact on persons from the Global South (Xiang Reference Xiang2020). However, the COVID-19 pandemic was further revealing of the organic lock-in between industry and society in the era of ‘anthropocene mobilities’ (Baldwin et al. Reference Baldwin, Fröhlich and Rothe2019; Adey et al. Reference Adey2021). It provided a window into how human mobilities interact with other types of mobility – in this case, the mobility of goods through traditional supply chains – which in turn created flow on effects in certain national labour markets. In this light, the interlocking of different types of mobility regimes gives rise to their own kinds of political economy through the logics of logistics (Cowen Reference Cowen2007; Cresswell et al. Reference Creswell, Dorow and Roseman2016), in which the mobility of labour plays an analytically important, but by no means qualitatively dominant role (Kaufmann et al. Reference Kaufmann, Bergmann and Joye2004; Glick-Schiller and Salazar 2013).

Last, but not least, the COVID-19 pandemic revealed the capacity for otherwise well-established normative complexes to shift or move, as new patterns and configurations emerge from infrastructural breakdowns or sudden disruptions (Adey et al. Reference Adey2021). In the case of international law, COVID-19 could be seen to accelerate existing structural trends, such as the ongoing privatisation of international legal services. For example, the pandemic led to further outsourcing of security functions (Mégret Reference Mégret2021), as commercial providers stepped to provide quarantine services in a number of countries (Bosworth and Zedner (2022). At the same time, new normative trajectories also emerged. For example, scholars began to invoke new schemes for migrant rights in the wake of the pandemic (Kysel and Thomas Reference Kysel and Thomas2020) and new mobility pathways emerged not only in practice, but also in law for ‘essential workers’ (Robin-Olivier Reference Robin-Olivier2020). In these ways, the COVID-19 pandemic revealed the classic elements of international law as a ‘crisis discourse’, as it provided a tool to develop international law and fill existing gaps (Charlesworth Reference Charlesworth2002; d’Aspremont Reference d’Aspremont, Mbengue and d’Aspremont2021). However, the COVID-19 pandemic also had a crystallising effect on other fields of law, such as international health law (Clements Reference Clements2024), and spurred across a wide range of legal developments as the normativity of public health became entangled in new legal domains (Gammeltoft-Hansen and Madsen Reference Gammeltoft-Hansen and Madsen2021). For instance, in Brazil during the onset of the crisis local authorities deployed WHO health regulations to militarise the border and deny migrants the protection of human rights law (Hoffmann and Nascimento dos Reis Santos Reference Hoffmann and Nascimento dos Reis Santos2024). In other circumstances, however, new trajectories in health law were rights-enhancing, as gaps in the legal architecture for migrants became sites for compassion. For example, Portugal adopted emergency regulations enabling irregular migrants with pending cases to be treated as ‘residents’, thereby securing their access to free public health care on par with nationals (Achiume et al. Reference Achiume, Gammeltoft-Hansen and Spijkerboer2020).

5 Conclusion: the space for critique in mobile ontologies

In this article, we have called for a fundamental rethinking of the mobility paradigm in international law, which pits territorial boundedness as the normal state of affairs, and considers transnational mobility as the aberration rather than the norm. We have argued that the failure of international legal scholarship to recognise the cardinal significance of mobility to international law is striking, as historically mobility has been integral to the development of international law – from colonial and mercantile origins to the formation of migration pathways.

At the same time, we have called for a broader rethinking of what mobility means for international law, and have sought to disassociate it from migration in order to embrace a broader focus on movement itself. Mobility is integral to the ontology of international law, as it provides the foundation for corporeal control and infuses territories and borders with the legal meaning through doctrines such as state sovereignty. Through the example of global tourism, we have sought to show how international law concretely exerts control over human bodies, through material devices such as the visa, practical implementation in means of border control and integration into socio-technical platforms such as the airport. The example of the COVID-19 pandemic further showed how mobility in international law functions as a process of co-constitution, whereby mobility shapes law and law shapes mobility – a hermeneutic cycle with no identifiable start or end point. This points in the further direction of thinking about mobility as a particular quality of law (Kmak Reference Kmak2024) as it characteristically ‘drips’ and ‘wobbles’ (Barr Reference Barr and Philippopoulos-Mihalopoulos2019) and extends its normative reach over new spheres of regulation, new activities and relations, through the mobility of interests, ideas and political paradigms.

At this point, it is worth reflecting on the added value for re-imaging the mobility paradigm at this post-pandemic juncture. While some scholars have regarded the pandemic as a potential ‘constitutional moment’ for international law (Shany Reference Shany, Mbengue and d’Aspremont2021), historical examples also highlight how real or perceived health crises may also have long-standing after-effects in the naturalisation of control over bodies (Xiang Reference Xiang2024). The invitation extends from this point to re-consider international law’s temporal and spatial scales, where ‘questions do not begin with [the givenness] of international space and progressive time’ (McNevin Reference McNevin2022), but from the larger scale of the ecosystem and the relational qualities of the smallest organism (Adey et al. Reference Adey2021). One particularly promising avenue in this regard is taking an empirical and critical focus on ‘mobility assemblages – constellations of actors, actions, and meanings that are influenced by mobility regimes that govern who and what can move (or stay put), when, where, how, under what conditions, and with what meanings’ (Sheller Reference Sheller2018), with a reflexive agenda that avoids the pitfalls of a priori reasoning and being open to unexplored potentials. The first potential that arises is for decentring mobility in law, because mobility is not just about crossing borders. The second is for decentring the mobile subject, because it is not only humans that are mobile. The final call is for decentring the role of law in mobility, because law is never static, but rather it recursively infrastructures society. What this may ultimately require is new ways of seeing law beyond a static circumference of vision – to appreciate its quality as a mobile property and a means of liberation and control.