Politics in an era of rising nationalisms is increasingly focusing on the definition and redefinition of “borders”: Borders are being boldly remarked and reaffirmed, as in the case of Donald Trump’s wall between the United States and Mexico, or reclaimed, as in the UK’s plan to withdraw from the European Union. Elections are now won or lost by proposing different imaginaries of how a nation’s borders will be managed and made more or less effective in screening those who want to cross them.

In Security at the Borders, Philippe M. Frowd offers a very original contribution to the debate on the changing nature of borders by focusing not on the obvious cases, those where the borders and the work they do are the most visible—such as in the case of the lines enclosing the European Union—but on those spaces where borders are silently externalized.

Mauritania and Senegal, the two countries at the core of this study, have progressively become outposts of practices of control promoted by actors in the Global North, seeking to expand their gaze toward places where migration originates, rather than simply trying to harden the lines when crossings occur. Instead of adopting a normative approach—flagging these practices as more or less problematic, or seeking to attribute different labels to the actors pursuing them—the author engages in an empirically grounded exploration of how these practices emerge and morph, and of the consequences they produce, with very rich results.

Frowd successfully combines personal accounts, such as those from the journey he embarked on from Nouakchott to Nouadhibou in Mauritania as part of his fieldwork, with theoretical reflections making sense of incidents and events. The multiple checkpoints encountered along the way become an opportunity to remark how “borders may be referential of geopolitical lines, but they can be exercised across territory” (p. 29). Elsewhere, the participation in trainings sessions organized by international and regional organizations (e.g., the International Organization for Migration or the European Union) is used to vividly illustrate the banality of the ways in which practices of control are proposed and adopted, as well as how “workshop fatigue” sets in among small communities targeted by programmes seeking to ensure compliance with new standards and practices (p. 137).

By engaging in a complex array of encounters with individuals and organizations involved in “borderwork” in Mauritania and Senegal (inspired, as Frowd honestly remarks, by ethnographic sensibility, rather than amounting to a long-term ethnographic work), the study offers a rich account of the complexity of the networks that define and redefine borders. Formal and informal actors cooperate and compete to affirm their authority, international organizations and governments in the Global North seek to introduce new practices, but it is uncertain how these practices can be deployed in remote areas that are out of reach of the most basic infrastructures.

As the analysis of biometric policies in Senegal illustrates, the overlap of different actors, interests, and motivations and the need to demonstrate that actions are being taken can lead to paradoxical outcomes. The most sophisticated technologies and controls are not necessarily introduced where they are the most needed, but where they are the most visible, such as Dakar Airport, where irregular migration presents the lowest risks. Similarly, the analysis of the deployment of a Personal Identification and Registration System (PIRS) in Mauritania illustrates how complexity may not be resolved by selecting a procedure or technology that appears to be the best fit for responding to a specific challenge, but by “buying time”—by delaying the need to make important decisions. Among different software products available, a piecemeal package was chosen to record entries and exits because of its ability to allow the inclusion of new features at a later stage, to comply with new demands and regulations. As Frowd illustrates, such decisions may temporarily respond to requests to act and innovate, even when it is unclear to what extent the chosen technology is able to solve a specific problem, or that a clear assessment of the “problem” itself has not been made, but at the same time they create a relationship of dependency with specific actors and visions of how border controls should be performed.

One of the most significant contributions of the author is to take into account and analyze how both human and technological actors connect and operate in enforcing different types of injunctions. Couched within the framework offered by Actor Network Theory (ANT), Frowd presents a strong case for technology that has become an essential component in expanding control not just at the borders but also in the myriad spaces where different forms of authority are attempting to extend their gaze: from European states seeking to map a growing population of potential migrants, to African governments strengthening their capacity to control and surveil their own citizens.

The power that technology exerts by making itself visible and invisible at the same time is vividly mapped through the interplay of numerous cases—from 4 x 4 vehicles donated by European governments and boats with EU flags moored in Senegalese ports to thermal imaging binoculars, e-passports, and sprawling databases with biometric information. Technology is analyzed for its ability to incorporate and automate functions previously performed by human agents, as well as for it capacity for introducing new possibilities to extend the legibility of a specific space or a population. But it is also considered for its symbolic potential, and for its power to send messages about changing regimes of control. Failures are also analyzed—even if the reader is sometimes left wanting for more details and reflections on their meanings and consequences. Fascinating cases of hybrids are presented where local practices have to be brought back, reinvented, or reconfigured to fill the gap left by a malfunctioning technology or one whose promises failed to materialize when deployed on the ground.

When the power of technology to be an actant in the coproduction of new security regimes is discussed, the language sometimes gets a bit apologetic, preempting criticism that embracing ANT does not mean attributing agency to objects. References to the history or technology tradition, and to how technological artifacts can perform different types of agency, depending on the regimes they become parts of and on their level of “closure,” could have helped in resolving this tension. They could also have provided a framework for analyzing, with greater nuance, the circumstances under which an artifact—or an assemblage—is more or less able to perform a specific function.

Security at the Borders holds promise to become an important reference for those interested in more complex understandings of how borders function (beyond reporting on the numbers of crossings, rejections, or expulsions): how they not only structure the relationship between the Global North and the Global South but have also become a tool for reorganizing power balances within states. A possible continuation of Frowd’s work could offer a much-needed account of the ways in which citizens and migrants perceive and work through borders, and how they may accept some elements of new border regimes while resisting—or seeking to escape—others.