This article argues that the dominance of precise, linear borders as an ideal in the demarcation of territory is an outcome of a relatively recent and ongoing historical process, and that this process has had important effects on international politics since circa 1900. Existing accounts of the origins of territorial sovereignty are in wide disagreement largely because they fail to specify the relationship between territory and borders, often conflating the two concepts. I outline a history of the linearization of borders, which is separate from that of territorial sovereignty, having a very different timeline and featuring different actors, and offer an explanation for the dominance of this universalizing system of managing and demarcating space, based on the concept of rationalization. Finally, I describe two broad ways in which linearizing borders has affected international politics: by making space divisible in new ways; and underpinning hierarchies by altering the distribution of geographical knowledge resources.

Introduction If one overarching pattern has shaped the geopolitics of the last century and a half, it has been the global linearization of borders. Unlike in previous eras, it is not considered enough to vaguely indicate an area or a frontier zone of a certain width, or to name certain places or jurisdictions in establishing control over territories. Since the late 19th century, it has been assumed that regardless of place or context, territories must have linear borders, ideally consisting of precise one-dimensional points on the earth’s surface, connected by straight lines. The linear ideal of borders and the practices of border delimitation and demarcation that make it possible to imagine the ideal as an accomplished fact have fundamentally affected virtually all territorial politics, from post-war peace settlements to territorial partitions. That a border can, in practice, be purely linear is a fiction as borders are always multifaceted, uneven and ambiguous to some degree, but it is a powerful fiction, and many polities have attempted to linearize borders. Yet, there have been few efforts to explain the historical process that brought the ideal of linear borders to dominate politics. Such concepts as ‘modern territoriality’ and ‘exclusive sovereignty’ are important for understanding the modern state, but they do not address issues of precisely how territory is defined, how territories are distinguished from each other and what consequences arise from a linear definition of territory (Sassen, 2006; Spruyt, 1994; Teschke, 2003; Tilly, 1992). These debates have tended to bundle historical changes in the demarcation of borders into a ‘Westphalian’ package coming to life concurrently along with state formation and sovereignty, going almost unnoticed as an analytically distinct process in itself. This article argues that the recent global consolidation of linear borders is not a politically neutral expression of territoriality, or simply territoriality taken to its logical conclusion. Instead, linear borders stem from a historically particular rationality and have distinct causes and effects. I proceed in four sections. First, I posit the insufficiency of existing International Relations (IR) approaches to the origins of territorial sovereignty for explaining the advent of linear borders. Second, I elaborate on the theoretical and historical distinction between territory and linear borders. Third, I outline an explanation for the linearization of borders using the sociological concept of rationalization. Finally, I describe two broad ways in which the linearization of borders has affected 20th- and 21st-century international politics: by enabling an acceleration and proliferation of territorial partitions; and by empowering certain states best able to manipulate the specific kind of geographical knowledge created through linear borders.

The linearization of borders as rationalization So far, I have focused on the times and places in which territory and linear borders have existed, and exposed the empirical difficulties with conflating them. However, if the linearization of borders is, indeed, comprehensible as relatively autonomous from territoriality, two additional things must be shown theoretically: that this process had some cause independent from or broader than territoriality; and that linear borders had some constitutive effect on international politics that cannot be attributed to territoriality alone. The following two sections, then, explore the origins and consequences of linearized borders. I argue, in this section, that the linearization of borders should be understood as an outcome of larger epistemic processes of rationalization and, in the next section, that this manifestation of rationalization in geopolitics has played a key role in the 20th-century proliferation of partitions, as well as in establishing ‘science’ as a powerful resource in geopolitics. There are some crucial insights from literature on the history of territoriality that are useful for our purposes here. On the one hand, what might be called ‘epistemic’ explanations point to the influence of increasingly atomistic notions of subjectivity in European society, art and literature (Larkins, 2010; Ruggie, 1993). On the other hand, ‘cartographic’ explanations stress the technology of map-making as enabling certain forms of territorial governance to be conceived of, before they could be implemented in practice (Branch, 2014; Strandsbjerg, 2010). These explanations of territorial sovereignty rely on an implicit concept of rationalization. Whether it is cartographic practices and technology or conceptions of subjectivity that are under consideration, these studies all allude to a shift or narrowing of what appears ‘rational’. Branch (2014: 92), for example, notes that ‘Frontier zones filled with enclaves and overlaps were “rationalized,” or made linear’, as part of the process of ‘territorializing the state actors involved in international politics’. Richard Ashley (1989: 290), similarly, identifies the ‘Cartesian practice of spatialization’, in which ‘resides the very possibility of rational political subjectivity’, as a source of modern sovereignty (see also Walker, 1993: 129). The rationalization of subjectivity and of cartographic practices referred to in such studies is a particular aspect of one larger bundle of processes. This process, by which forms of knowledge and order perceived as traditional, mystical, arbitrary or unclear were delegitimized in favour of those that seem rational, was termed ‘rationalization’ and first theorized as such by Max Weber. Weber (1988: 30) believed rationalization to be ‘the fate of our age’, and while his analysis of bureaucratic rationality is particularly well known in IR, he wrote about its effects in a wide variety of domains of life, such as theology, law and even music theory. Weber wrote little about political geography, despite including a territorial requirement in his definition of the state, which offers no reflection on the nature of a territory’s borders (Weber, 1991). Yet, the framework of rationalization is helpful for understanding the process of the linearization of borders and its constitutive effects on international politics. Processes of rationalization can be broken down into three components that are of concern to linear borders. First, concepts were pushed to the highest levels of abstraction and generality, while the particularities of concrete things, people and places were to be understood only through general categories. These abstractions then became rules used to order practical action, descending back down to the level of the concrete. Finally, these rules were actively spread horizontally to new areas in order to ensure their conformity. Privileging the abstract over the concrete The first step in processes of rationalization involves the creation of concepts and abstract systems of thought, in place of direct action (Kalberg, 1980: 1152). Such systems of thought, which Weber calls ‘theoretical rationality’, were crucial in disavowing all magical and mysterious forces, and comprehensively explaining human suffering and the meaning of existence. In the late 16th century, for example, the Renaissance humanist interest in ethnographic, geographic and historical concreteness and particularity gave way to the generalized laws of the scientific revolution (Toulmin, 1992: 32). With the growth of 17th-century physics, the concept of ‘place’ came to be defined only by the general characteristics of all places that could be abstracted from any place in particular, such as size and distance from other places, and were thus subordinated to a more generalized and homogeneous notion of Cartesian space (Casey, 1997). To be clear, the important shift here is not towards fuller knowledge of the conditions of human life, but rather towards the belief that ‘if one only wanted to one could find out any time’ the answer to any particular question about this natural, disenchanted world (Weber, 1988: 13). Three particular systems of abstraction laid the groundwork for the development of linear borders. First is the Renaissance adaptation of Ptolemy’s system of latitude and longitude. As standardized under the Greenwich Meridian, this powerful system of spatial epistemology relies on only two particular objects: the rotational axis of the earth and the Royal Observatory at Greenwich. In theory, it allows one to determine one’s location ‘objectively’, or, given a set of any technically possible coordinates, to locate the one spot on the earth’s surface that corresponds to it. Any ambiguity or error can be attributed to the instruments used or the interpretation of their output, but not to the system itself. Second, alongside this spatial epistemology came the ontology of bounded, formally equivalent, self-contained geographic entities, as began to be represented in early-modern European maps (Biggs, 1999). In the same way that abstract equations define objective laws of motion, even if never precisely observed in practice, the fact that frontiers can only ever tend towards a line is overlooked in the search for geometrical abstractions. The connection between these two systems is made necessary by a third one: international law. The project of international law has, from its origins, been an application of allegedly universal reason on the global scale (Anghie, 2005). For Francisco de Vitoria, it was a novel solution to the gap between the legal systems of Spain and that of the Native Americans that the Spanish encountered, based not on Christian divine law, but on the universal reasoning ability of humans. Yet, some nations were thought to be organized more rationally than others and were therefore more civilized (Patterson, 1997: 35). Refashioning the idea of Christendom into a secular ‘European’ civilization distinguished European nations from non-European nations primarily on the basis of their rational civilization. It was this international law founded on universal reason that would purportedly entitle European powers to draw definitively fixed borders, not only between each other, but also in all parts of the world. Putting abstractions into practice Along with these newly ambitious abstract systems of knowledge came attempts to apply them back to the concrete reality from which they were extrapolated and use them to reshape the world. Through the disenchantment of theoretical bodies of knowledge, it became believable that ‘one can, in principle, master everything through calculation’ (Weber, 1988). The Cartesian idea of the rational mind as an architect planning imaginary structures first, free from the complexity of the world, and only then building them in reality maintained the priority of the abstract over the real (Mitchell, 2002). Weights and measures were standardized, and forests began to be managed and planted in rational patterns in the late 18th century (Scott, 1998). Even frontiers had to be ‘rationalized’ according to military logic (Branch, 2014: 155). Historically, divine forces have often appeared to assist in the fixing of boundaries (Stilgoe, 1976). In ancient Rome, for example, the god Terminus presided over property boundaries, which had to be marked, and moving these markers was not only illegal, but also sacrilegious. In early-modern England, villagers accompanied clergy on an annual walk tracing parish boundaries, saying prayers and chanting psalms. The politics of locating and relocating boundaries often gave a role to divine powers that could never completely be captured by human understanding. However, with the removal of mysterious forces from the world by rationalization, it was left to human imagination and design to fix boundaries. The 1494 Treaty of Tordesillas, which was perhaps the first attempt to create a large-scale linear border, was originally guaranteed by the spiritual authority of the papacy (Branch, 2012). Yet, as international law developed, it increasingly derived its authority instead from its self-evident rationality, having been elaborated by ‘rational’ civilizations. Inter-imperial agreements such as that concluded at the Berlin Conference of 1884 reveal empires attempting to set down rules that would rationalize colonial activities and effectively manage their projections of power on the continent. It was the calculability of state interests that had given rise to the idea of a ‘balance of power’ that guaranteed these boundaries, not religion or mystical powers (Bartelson, 1995: 181). In addition to what was now believed to be institutionally realistic, technological developments were applied to make linear ideals a reality on the ground. Using the Ptolemaic system of latitude and longitude, by specifying a series of connected coordinate points, called ‘turning points’, borders can be reduced to little more than a series of numbers, such as the following definition of the Saudi–Jordanian border (US Department of State, 1965): TP No. 1 Jabal ‘Anazah; 32° 14’ North and 39° 18’ East; tripoint with Iraq TP No. 2 32° North; 39° East TP No. 3 31° 30’ North; 37° East TP No. 4 30° 30’ North; 38° East TP No. 5 30° 20’ North; 37° 40’ East TP No. 6 30° North; 37° 30’ East TP No. 7 29° 52’ North; 36° 45’ East TP No. 8 29° 30’ North; 36° 30’ East TP No. 9 29° 11’ North; 36° 04’ East TP No. 10 29° 21’ 30” North) indicate as approximate position 34° 57’ 30” East) of coastal terminal point. Beginning in the colonial New World, then, European empires began to divide real space with theoretical lines. This gave the impression that space had been rationally planned first, and then simply implemented according to plan. Contrary to appearances, however, the linearization of borders has rarely, if ever, been completed precisely according to any comprehensive plan. Instead, linearization is a continuous process, often characterized by an oscillation between the failure of the world to conform to abstract concepts, and the creation of new abstract concepts in order to correct for the previous failure, with first principles never being called into question. As an illustrative example, consider the roughly three hundred years of boundary disputes between the colonies, and later states, of Pennsylvania, Maryland and Delaware (Bayliff, 1959). The southern boundary of Pennsylvania was originally set at 40° North, but it was later discovered that Philadelphia, the main city of Pennsylvania, was south of this line. Thus, an agreement was reached between the three colonies whereby the Pennsylvania–Maryland boundary would be moved south, and Maryland would receive part of Delaware in exchange. However, this agreement could not be implemented either because it required delimiting a radius of 12 miles around New Castle, Delaware, a town with no obvious centre point. A further agreement specified the centre as the cupola of New Castle’s Court House, but then when a 12-mile radius was drawn from there, it did not quite reach the north-east corner of Maryland, and a thin wedge of territory was left outside each of the three colonies. It was not until 1921 that this wedge became part of Delaware. One solution to this problem, endemic to all attempts to linearize borders, was conceptualized by British colonial official Henry McMahon: separate the task into two parts, one political and one technical, otherwise known as ‘delimitation’ and ‘demarcation’ (Rushworth, 1997). This distinction is still used in Border Studies today. Agreement on the general course of the boundary should be reached first by diplomatic negotiators, and only then, once a political agreement was reached, should geographical technicians set out to physically mark the boundary however possible. The impossibility of total knowledge of the world would be incorporated into this system of rationalization by establishing a certain amount of freedom to be given to the technicians to demarcate the boundary according to the reality of the world rather than confining them to a geographically ill-informed treaty. Yet, this could not solve the problem completely because it never revisited the first principle of the entire system: the essentially linear nature of borders. Privileging the universal over the particular The first two elements of rationalization entailed the linearization of some borders. Yet, linear borders coexisted alongside other methods for centuries. Some borders dead-ended in continental interiors, and most states in Europe still lacked linear borders in the mid-18th century, even when they possessed colonies in the Americas that had them (Branch, 2012). However, by the end of the 19th century, imperialists were making more and more deliberate efforts to linearize borders as a universal rule rather than one among many possibilities. Weber’s concept of ‘formal rationality’ can help us understand this universalization (Kalberg, 1980: 1158). Under conditions of formal rationality, which Weber sees as taking shape most clearly in the industrial era, all action in any particular domain has to be oriented according to one objective set of principles. Formal rationality differs from ‘theoretical rationality’ and ‘substantive rationality’, in that rules dictate everything, ‘without regard to persons’, rather than particular worldviews or values. The universalization of linear borders, I argue, is part and parcel of this larger historical shift towards uniformly applied rules. The transformation of British views of Afghan territoriality over the course of the 19th century is particularly indicative of an increasingly uncompromising application of universal rules, disregarding local concepts. Earlier in the century, in describing the ‘limits of the kingdom of Caubul’, diplomat Mountstuart Elphinstone had drawn on ‘the test made use of by the Asiatics themselves’, and considered ‘the King’s sovereignty as extending over all the countries in which the Khootba is read and the money coined in his name’ (quoted in Bayly, 2016: 78). However, by the later part of the century, a British official could state that, in fact, ‘there is no such thing’ as an Afghan boundary (Bayly, 2016: 244). Where did these boundaries go? What changed was not the ability of imperial agents to access knowledge, but rather that local knowledge did not correspond to the universal principle of linear boundaries. Consider the Pamir mountains in the far north-east of Afghanistan, described by George Curzon, the future Viceroy of India, as: so lofty in situation, fast bound in the fetters of frost and ice during eight months of the year, almost destitute of vegetation, swept by hurricanes … the ownership or boundaries of which none are able, and few are anxious, to determine. (Ewans, 2008: 240) Yet, despite making boundary-drawing in this region seem an absurdity, Curzon could not entertain the possibility of this boundary remaining ‘haphazard’ and ‘irregular’. In order for this to happen, the decisive step had to be taken by Enlightenment thinkers to assert that Western ideals were not only superior to other ideals, but also had to replace them. Forms of colonialism that explicitly worked within local knowledge were delegitimated, and European technology and scientific expertise was increasingly thought of as a measure of this superiority (Adas, 1989). For many observers, the arbitrariness of a frontier lacking official definition came to signify a ‘backwards’ civilization. According to followers of the German geopolitical tradition, linear borders emerged when ‘civilized’ societies neighbouring each other exerted mutual pressure that forced them to adopt a rational use of the land, and eliminate any unused middle ground (Semple, 1907: 390–392). ‘Uncivilized’ societies, on the other hand, apparently did not feel such pressure. For Curzon (1907), ‘In Asia, the oldest inhabited continent, there has always been a strong instinctive aversion to the acceptance of fixed boundaries … partly from the dislike of precise arrangements that is typical of the oriental mind’. The adoption of fixed boundaries, in global-historical terms, is often associated with the proliferation of nationalisms and national states, while many empires are thought to have been antithetical to the fixing of boundaries (Anderson, 2006; Maier, 2017: 14–81). However, comparing bordering practices and discourses in metropoles and colonies complicates this view, first, because border linearization was first attempted in colonies, not metropoles (Branch, 2012). Moreover, the linearization of borders in most of the world occurred under the auspices of formal or informal empire, whether through inter-imperial border commissions or through British or American arbitration. The academic field of Border Studies owes its foundation in large part to a group of imperial officials grappling less with the problem of attaching a national identity to a particular territory than with the problem of rendering unfamiliar spaces intelligible and safe for imperial expansion by fixing inter-imperial limits (Curzon, 1907; Holdich, 1899; Rushworth, 1997). Regardless of the context, these officials assumed the rationality of linear borders and argued that precise borders would help ‘civilize’ spaces that they found difficult to govern. While Weber was sceptical of rationalization processes, believing them to restrict human freedom and contradict their originally intended purposes, the limitations of rationalization are outside the scope of this article. The important point here is that rather than a politically neutral expression of territory or sovereignty, then, linear borders delimit territory in terms of a historically particular rationality that affected a wide range of social domains and reached a new height in the industrial era.

The consequences of spatial rationalization International politics in a world made up entirely of theoretically coterminous, interlocking territories with linear borders is different from politics in a world of multiple acknowledged forms of territoriality, or less clearly defined frontiers. There are certain forms of politics that have been characteristic since around 1900 that were impossible without linear borders, even in the relatively well-defined territories of ‘Westphalian-era’ Europe. I describe two here: first, the acceleration of territorial partition particular to the past century or so; and, second, the specific form of power derived by some states through cartographic technology. Partition One remarkable pattern in international politics since the early 20th century that has been noted in IR is the increasing number and decreasing size of polities, in contrast to the previous decades, which were marked by decreasing numbers and increasing sizes (Griffiths, 2016). At first glance, there is a striking correlation between the time at which linear borders crystallized as a global standard of territorial definition, in the late 19th century, and the time at which a process of global partition began. Linearized borders alone did not cause this global partitioning. They did, however, enable and accelerate the process in three ways: by making territory appear more readily divisible; by abstracting spatial considerations from other issues; and by creating a modular process of partition that could technically be transplanted to any place in the world. First, linearized borders help make space divisible in new ways. A number of IR scholars have investigated the conditions under which actors are unable to partition territory (e.g. Goddard, 2006). However, if we expand our analysis outside times and places where linear borders are the assumed way of defining authority, how territory becomes divisible in the first place is equally in need of explanation. Any effort to partition is always limited by the concepts and knowledge possessed by decision-makers. Conceptually, space may be made up not of homogeneous, infinitely divisible space, but rather of a finite number of socially constructed regions, provinces, counties and so on. At some point, divisions and subdivisions of these are likely to reach a small enough sub-region that dividing it is no longer meaningful to a sizeable social group, and there is no guarantee that such a strategy would be useful or available to negotiators. Linear borders mitigate the obstacles to creating radically new boundaries, or at least they can appear to do so from the bird’s-eye perspective of authorities. As long as it can be mapped and has area, a territory can be split into smaller areas in a technically infinite number of ways. Linear borders make it possible to imagine that an objective and reliable division can be created, even if it has very little in common with existing arrangements, or cuts across local habits and customs. The 1947 partition of India, for example, divided the provinces of Punjab and Bengal in a way that would not likely have made sense before the linearization of borders, using only very small administrative divisions and cutting across thick spaces of landownership (Chatterji, 1999). It was typical for individuals to use and hold various kinds of rights over many disparate plots of land, meaning that the partition criminalized the networks and routine transactions that sustained much of the countryside. The earlier Mughal administrative divisions, which were not so linear, had accommodated these transactions (Michael, 2007). When British administrators arrived, they found it difficult to understand the existing divisions as they found them constantly shifting and filled with enclaves. Over the course of their nearly two centuries of rule in India, they linearized the borders of these divisions, but this did not completely eradicate earlier patterns of land usage. The commissioner for the partition, Cyril Radcliffe, was chosen not despite the fact that he had had no experience with either India or boundary-drawing, but because of it, which the government hoped would put him beyond suspicion of partiality (Chatterji, 1999: 186). He did, however, have maps and data at his disposal, and, by design, it was largely on this basis that he made his decision, which would likely have been very different if not for the assumption that a simple linear border could be, and had to be, drawn. Divisibility is only one precondition of territorial partition that linear borders accentuate. Another is what might be called ‘territorialization’. Territorialization is the process by which issues are transformed from less clearly territorial to more clearly territorial, or, in other words, how the issue of how to distribute space between actors becomes distinct from other issues. Linearizing borders facilitates this process of territorialization as a form of rule that is both abstract and concrete. As an inherently abstract system, it helps conceptually separate territory and its contents, and thus provides a clear way of differentiating between territorial and non-territorial strategies of rule. Nearly any political problem, from a particular perspective, can appear to be a problem of defining borders in the right way. The more that borders become conceptually tied to a global geometrical system of reference rather than concrete practices of rule, the easier it is to imagine territorial politics as a distinct and autonomous sphere of politics. It is through the global linearization of borders that the question of division becomes an already identifiable and potentially conflict-engendering possibility. While they are characterized by abstraction from people and objects, linear borders, when mapped, appear to give territory a physical substance that can be measured precisely. When Thongchai (1994) refers to the creation of Siam’s ‘geo-body’, it means not simply territory, but territory with mappable borders, and it is Thongchai’s contention that these borders gave the Thai national space a more tangible existence. While Siamese territorial entities had existed previously, it was only through this recent process that a Thai nation itself was territorialized (Thongchai, 1994: 134). Linear borders provide an appearance of precision and measurability to some social facts, such as identity, which would often otherwise seem more ambiguous and imprecise. In a rationalizing world in which virtually all areas of life demand certainty and clarity, identity can prove disconcertingly fluid and vague to be deployed as a basis of political contestation, but linear borders seem otherwise, and can thus be used as a proxy. Finally, because linear borders are theoretically applicable anywhere, experiences gained from one partition can affect others, and disparate issues can become linked. Like Benedict Anderson’s (2006) nationalisms, partition has become a ‘modular’ phenomenon, capable of being reproduced and appropriated for different purposes in different places. When we take multiple cases of partition into account, then, we have to consider the effect that they have on each other. Partition is, by now, an experience shared by a wide range of peoples, from Korea to Ireland, and the more that different partitions resemble each other, the greater the possibilities for transnational links to be forged based on these experiences, with issues in different places becoming linked and imperial officials transferring their experiences from one partition to the next. In particular, the partitions sponsored by the British Empire in many places, including Ireland, Palestine and India, are connected not only by comparisons that might be drawn in hindsight, but also by direct links. India’s close involvement within the United Nations (UN) on arrangements for Palestinian independence had everything to do with its own ongoing partition into Hindu and Muslim areas (Kumaraswamy, 2010). According to one historian, many in Ireland, similarly, have viewed Israel as a ‘little Jewish Ulster’, taking a term coined by one British colonial governor, and such perceived parallels have engendered ‘an emotional connection with Palestine that has inspired Irish activism in the region up to the present day’ (Miller, 2010). Several British officials, such as Reginald Coupland and Leo Amery, were influential in both the Indian and Palestinian partitions (Fraser, 1984). While many individual and comparative studies of partition exist, little work has been done to appreciate the mutual influences between and transnational links created by partitions, many of which have been made possible by the apparent universality of linear borders. In sum, linearized borders make partition less immediately contingent upon particular socially constructed regions and more likely to appear as a solution to the ambiguities of identity politics, and allow partitions to feed off of each other and proliferate globally. The scientific peace: The politicization of geographers The linearization of borders is inseparable from historically particular, ‘scientific’ types of knowledge, and it can empower experts of a certain kind and the states that employ them. At peace negotiations, for example, the impact that one group or state has on the ultimate result has to do not just with its military or economic power, but also on its power in terms of this particular kind of knowledge. While geometrical, mathematical and statistical knowledge appear obviously applicable to linear borders, other geographies, such as those of lived experience, no longer seem necessary. The impact of scientific discourses on international politics has been approached in a number of different ways previously (Mayer et al., 2014). The goal of this section is to set out the role of the linearization of borders within the co-constitution of science and international politics, and to argue that scientific discourses constitute an important source of power by limiting the kinds of knowledge considered valid. When borders are ‘hereabouts’, no group is necessarily better positioned than any other to identify them. Without centralized records of linear borders, polities as widely ranging as France and Siam historically depended on local inhabitants to know where exactly boundaries were (Buisseret, 1982; Thongchai, 1994). Linear borders, however, being conceptually limited and geometric, narrow the kind of knowledge that appears useful for this. Knowledge of lived experience or of gods no longer has any obvious bearing. Instead, the knowledge resources that are socially constructed as useful tend to be survey techniques, demographic cartography and, more recently, computerized Geographic Information Systems (GIS). These techniques provide the geometric ‘footholds’ necessary to enable mathematics to be used directly in peace agreements, increasing the leverage of states that have access to particular knowledge resources. In practical terms, when scientific methods are considered a necessary part of a peace agreement, certain people and instruments can prove very valuable in effecting a desired outcome. For example, in the negotiations over the 1995 Dayton agreement on the partition of Bosnia, when both sides of the conflict agreed to a territorial division of 49% to 51% by area, they became dependent on a team of US computer technicians to repeatedly carry out complex geometrical calculations parallel to the negotiations (Holbrooke, 1999: 295). These calculations became so important that negotiations were almost derailed when one party realized that some results had been kept secret. Moreover, in terms of legitimation, the involvement of scientific methods can serve to obscure political interests, making an agreement appear to be objective and fair. In contrast to a type of contestation that is perceived as ‘political’, where outcomes seem to be decided by the powerful, the more a negotiation appears to be conducted according to a ‘scientific’ logic, the more outcomes seem to be decided according to what is objectively true. The impact of the privileging of specific kinds of geographical knowledge often becomes clear in peace negotiations, such as the Paris Peace Conference of 1919. Bringing the First World War officially to a close, the Paris Conference was centrally concerned with territorial changes in Europe, drawing three thousand miles of new borders (Crampton, 2006; Smith, 2003). With the collapse of the major continental European empires, the victorious Allies sought to balance resurging national aspirations against each other, along with their own interests, in a turbulent, revolutionary context of scattered continuing warfare. The difficulties of drawing linear borders cartographically separating intricately intermixed national groups were well known, but the assumption of linear borders was never seriously questioned, resulting in an advantage to those who could best manipulate them. Examples abound of this kind of power at work at the Paris Conference. For example, some argue that the conference’s favourable views of Yugoslav territorial claims, at the expense of other states of similar size, had much to do with the fact that a Serbian geographer, Jovan Cvijic, who was acclaimed for his ‘scientific attitude’, was highly trusted and involved in the decision-making process (Crampton, 2006: 743). The US exercised a similar kind of power through scientific plausibility, using a specially designed body of experts, called ‘The Inquiry’ (Gelfand, 1963; Smith, 2003). President Woodrow Wilson set up the Inquiry in 1917, only a few months after the American declaration of war, bringing together a large group of mostly academics from various disciplines. It was an unprecedented effort, in type and scale, to compile and process scientific knowledge ahead of negotiations. As it was unmatched by any of the other delegations, the US had the only delegation that was able to assemble a concrete set of proposed borders for the whole of Europe in the early stages of the negotiations. The Inquiry, and other efforts like it, had an important impact on the outcome of the conference. Without this supply of carefully presented facts and expertise to counter opposing claims and arguments, Wilson’s much-ridiculed project of a just and fair settlement could easily have been marginalized by the conference. As a historian of the Inquiry put it: It is virtually inconceivable to think of the peace treaties of 1919 assuming the form they did without benefit of the enormous preparatory effort exerted by the Allied governments and the United States.… Perhaps there is no better measure than the work of the Inquiry to indicate that the United States by 1917 had reached the status of a great power. (Gelfand, 1963: 333) In practical terms, the expectation that precise borders would be agreed on at the conference created a demand for a particular kind of knowledge, which the US was able to supply. As noted by Isaiah Bowman, the head of the Inquiry, ‘Unfortunately, nations cannot be separated approximately. A boundary has to be here, not hereabouts’ (Branch, 2014: 140). Command over socially privileged forms of geographical knowledge was particularly determining in areas of Europe such as the Balkans, where the most powerful states were not highly invested in any particular outcome as long as agreement on borders could be reached. These time-consuming tasks were usually handed down to territorial commissions — often including Inquiry members — with almost free reign to draw borders. According to one observer, ‘most of the articles in the treaties were taken bodily without change from the reports of the commissions’ (Smith, 2003: 150). In terms of legitimation, moreover, the message of Wilsonian self-determination risked perceptions of naivety at the negotiating table unless it could be backed up with cold, hard ‘science’. As Wilson and Bowman both understood well, maps always made political choices in terms of what to include or exclude, but they could be very persuasive by taking on an appearance of neutral objectivity. As Bowman put it, ‘A map was as good as a brilliant poster, and just being a map made it respectable, authentic. A perverted map was a life-belt to many a foundering argument’ (quoted in Smith, 2003: 147). Despite inexperience and internal divisions, it was perhaps primarily the Inquiry’s use of maps, made possible by linear borders, for which the US drew praise from other delegations. Throughout the last 150 years, territorial conflict and contestation have played a major role in international politics, and it has mattered greatly that only territory which is specified in linear terms can be claimed legitimately. While there may be many reasons for this, I have argued here, in particular, that linear borders enable new patterns of territorial partitions and empower states with access to a particular kind of geographical knowledge.

Conclusion This article has argued that the linearization of borders, as a global phenomenon, is historically recent and constitutive of international politics, in contrast with other accounts of the origins of modern international politics, which take borders as simply an expression of territorial sovereignty. This conflation of borders and territoriality, I argue, has obscured understanding of some of the major patterns in the territorial politics of the last century and a half. The consolidation of linear borders as the global currency of territory has several implications for IR. First, this article has aimed to close a gap within existing explanations of the origins of modern international politics. While much historical IR literature has been devoted to the origins of modern territoriality rather than borders, this article has pointed to processes of rationalization as a basic framework for explaining the particular kind of border that currently dominates world politics. The explanations that do exist in the literature, moreover, often fall into this framework, whether they stress developments in ‘rational’ cartographic representations of statehood or ‘rational’ conceptions of sovereign subjectivity. Borders thus have a history that is interrelated with but separate from the history of territory; this is important because it opens up new areas of study. Neither sovereignty nor territoriality fully captures the peculiar condition of the modern world, whereby every coordinate point on land, besides Antarctica, theoretically corresponds to one and only one state territory. Nor does it account for the particular way in which struggles over maritime regions are currently unfolding over lines such as the meridians of the Arctic and the ‘Nine-Dash Line’ of the South China Sea. While various opposing claims to sovereignty in these areas have been made, what remains less often questioned is why they almost invariably take a linear form, rather than referring to particular islands or shipping routes. Whether or not states will make more consistent efforts to draw planar boundaries between themselves and outer space, moreover, is a fundamental question in the law of outer space (Cheng, 1997). Second, the recent global dominance of linear borders sheds new light on and raises new questions about the future relevance of linear borders as a form of territoriality. On the one hand, it suggests that, contrary to some versions of globalization theory, we may currently be seeing the beginning rather than the end of linear borders. The functions, significance and particular locations of borders have undoubtedly been subject to fluctuation, dispute and violent contestation, and are likely to continue to be. Practical experience of real border regions may reveal quite starkly the inadequacy of the idea that borders generally tend to be linear. Yet, serious efforts to undermine this idea remain limited and marginalized. On the other hand, the origins of linear borders within a very particular rationality suggest that the longevity of linear borders as such may be subject to the same limitations as this type of rationality. Theories of rationalization remind us that forms of knowledge that appear rational in one time and place will not necessarily always do so. The Enlightenment idea of abstracting worldly phenomena into pure forms, and attempting to universally apply such forms in practice, in other words, may not always serve as a basis for understanding political geography. For example, some states have found their purposes better served by allowing local border guards to pursue their own policies, rather than applying a top-down idea of frontier policing (Gavrilis, 2008). If this were to be extended beyond governing institutions to the fundamental concept of borders themselves, borders could conceivably be de-linearized in particular cases where this made them easier to govern from a local, rather than a centralizing, cartographic perspective. While such an unravelling of linear borders seems far off from a contemporary standpoint, theories of rationalization may hold the key for understanding when and where it could potentially occur.

Acknowledgements For insightful and productive comments and advice on previous versions of this article, my sincere thanks to the editors and anonymous reviewers of EJIR, as well as to Tarak Barkawi, Jordan Branch, Mark Hoffman, Alvina Hoffmann, Oliver Kessler and Jonathan Wyrtzen.

Funding

This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

Notes 1.

A loose definition of ‘defined territorial boundaries’ may be intended here, but, as with the concepts of ‘territorial sovereignty’ and ‘exclusive authority’, terminological ambiguity can obscure changes in the meaning of the term as it is applied to different times and places. 2.

Likewise, I use territory as an ideal-type referring to a somehow specified area within which a polity locates its authority. This is very different from historicizing the concept of ‘territory’ as it is used in discourse. (Elden, 2013). The distinction is important because while the latter must be located within a very particular historical context, polities have specified their authority geographically in a wide range of historical contexts.

ORCID iD

Kerry Goettlich https://orcid.org/0000-0002-1225-1478