(Editor’s Note: This article is part of a Just Security series in conversation with the new book, The President and Immigration Law, by Cristina Rodríguez and Adam Cox. The series will bring together expert voices on immigration policy and reform to reflect on the book and to chart a path toward a more sustainable and balanced immigration system. All articles in the series can be found here).

Unprecedented flows of people across borders during the last decade have strained the infrastructure, legal systems, and often the social fabric of nations encountering them. The humanitarian crisis at the U.S.-Mexico border, in 2014 and again in 2019, starkly illustrate the challenges posed by mass migration for countries both of origin and destination.

Disarray and uncertainty characterized the handling of migration and border issues both in the Obama and Trump administrations. Like Tolstoy’s families in Anna Karenina, each of the unsuccessful efforts faltered in its own way. Nonetheless, in the aftermath of the migrant crises that battered North America between 2014 and 2019, general lessons from these cases can be gleaned to shed light on how a more satisfactory border management system might be designed.

In their recent book, The President and Immigration Law, Adam Cox and Cristina Rodríguez expect the executive power – the president in the U.S. context – and the discretion attendant to that power, to continue to play the central role in formulating and executing immigration policy and enforcement priority in the continued absence of legislative action.

This commentary concurs in that assessment but places greater emphasis on the president’s constitutional authority to conduct foreign affairs as the key to understanding contemporary executive dominance over issues of migration and immigration policy. These matters in a global setting have become inherently transnational. There is hardly anything related to migration that does not have a cause or effect generated abroad.

The “externalization of borders” is breaking down old dichotomies by which policymakers and analysts in the past drew meaningful distinctions. A complete distinction between “foreign affairs” and “domestic affairs” or between “national security” and “homeland security” is no longer valid. A more reliable guide to navigating these perspectives lies in viewing their subject matter not in terms of bright lines but rather as a continuum. (Bayless Manning, for example, referred to the U.S. relationship with Mexico and Canada as “intermestic” in nature).

Lines and Flows: The Changing Nature of Borders

Nation states presently are ill equipped to distinguish between and manage the various flows of human migration at the scale we confront today. Immigration processing systems, asylum courts, and border enforcement agencies increasingly are overwhelmed. Without the legal, bureaucratic, and technological capacity to formally and timely process and manage inbound migratory flows, a large and increasing portion of these flows will remain irregular and undocumented. The mismatch between the volume and nature of migrant flows, and the sovereign capacity to constrain or manage them – evident recently in Europe as well as the United States – requires a change in our understanding of territorial borders as well as in the art and science of border management.

Borders traditionally have been viewed as lines in the sand (and on a map) demarcating the edges of sovereign states (or empires) according to the Westphalian system. Dating from the 17th century, this system inaugurated principles of mutual respect for national border boundaries, the territorial integrity of states, acknowledgement of the plenary authority exercised by a sovereign within their jurisdiction, covenants of non-interference in internal affairs of other states, and the legal equality of states in international affairs. Nation-states, consistent with this territorial and horizontal concept of sovereignty and the prerogatives which attach to it, assert their authority most aggressively at their borderline boundaries by determining who and what may enter or exit the geographic space and when, and the conditions under which, they may do so. This exercise of sovereignty at national borders has long been a means for governments to control the cross-border movement of people and goods.

Particularly, therefore, in today’s global context, highlighted by recent episodes of mass migration, borders should be conceived of as entry/exit points of flow—dynamic geographic spaces—as well as lines marking sovereignty. This new understanding of borders as lines and flows challenges the classical Westphalian conception of borders as “hard” boundaries around the territories of sovereign states. In other words, “borders” must be viewed as incorporating flows – the sum of which constitute globalization, with its continuous movement around the world of capital, labor, cargo, people, goods, services, ideas, images, data, and electrons – toward and across lines marking national sovereignty and managed as interdependent networks between and among nations, rather than solely as jurisdictional lines to be endlessly fortified and defended in situ by one nation-state.

The Geography of Management and Enforcement

It has become clear that nation-states cannot successfully manage migration at the border line of their territorial boundary itself. This boundary, the ports of entry situated on it, and the corridors between them, are increasingly the last line of defense rather than the first line of defense they traditionally have been considered.

Border fortifications and fences are of little utility in the case of migrants seeking to find and present themselves to border guards in order to initiate refugee and asylum processes. In this context, governments wishing to avoid scenes of chaos at the border must enlist time and space – and other nation states – in order to manage these flows as far away geographically from the border line as practicable and as early in time as possible before they arrive at the territorial boundary.

Implicit in this arrangement is the movement from bilateral border relations to binational relationships transnationally. Borders can no longer be managed satisfactorily on a unilateral basis from one side or the other. Legal authorities and enforcement power must be exercised to identify, intercept, and neutralize irregular migratory movements toward the homeland, well before they arrive at a port of entry on the border.

This altered paradigm regarding the border security mission has fundamental implications for a border management agency’s strategic and tactical approach to organization and function. Executive agencies will need to rethink their approach to and relationship with other nations as well as with partner agencies within their own government.

Both the Obama and Trump administrations have acknowledged the crucial role that Mexico and the sending countries of the Northern Triangle play in U.S. migration policy. Although their style, methods and motivations differed to be sure, each administration (finally) understood that diplomacy and foreign affairs were the principal tools to be deployed in the circumstances they confronted.

Rethinking Multilateralism

The post-World War II approach to tailoring multilateral action in (virtually complete) deference to national sovereignty has run its course. The lack of clear and accepted jurisdictional authorities, the absence of shared regulatory standards, and the weakness of multilateral organizations complicate the management of global “borderless” phenomena, including irregular migration toward and across border lines in the modern era. We need bold new thinking and the enunciation of acceptable supranational principles to govern a precise reengineering of strategy and doctrine. These in turn could lead to new theories of action that can elaborate revised tactics, devise strong modern mechanisms of collaboration, and develop a politically viable way forward. We need to create, over the next generation, a global migration management network that connects, in much more seamless fashion, national systems to multinational organizations. The resulting network must address existing gaps in intelligence collection, analysis and dissemination, and operational coordination sufficient to regulate cross-border movements of people, both regular and irregular.

The role of the U.S. president in this transformation is unique and essential. The constitutional arguments for vesting power over foreign affairs in the executive rather than legislative branch are increasingly salient as the management of borders depends increasingly on transnational relationships that reach far beyond the territorial boundary and require diplomatic negotiation. In this sense, modern border management hearkens back to the “Diplomatic Origins of Immigration Law” described by Rodríguez and Cox. The executive must take a lead role in managing the modern border, including in the negotiation and articulation of supranational principles to guide the management of transnational flows of people.

In the interim, individual nation-states will exercise sovereign power to protect their territorial integrity and the security and safety of their citizens. However, it remains true in contemporary circumstances that no single government can effectively counter mass migration surges on its own without the assistance of a multilateral support network, including a workable alliance with neighboring countries. To build and oversee these revised relationships, will require: (a) new international standards regarding national and international collaboration; (b) compiling global databases composing an international “data mart” regarding the movement of people; and (c) new transnational mechanisms authorized and equipped to coordinate actionable responses for existing “quasi” or “failed states” that compose some countries of origin today.


The post-World War II order is weakening in the genuinely epochal transition underway in the world. Mass migration is a principal symptom of the resulting dislocation. Because it is so visible and the source of substantial rancor and division within destination countries, including the United States, migration may be a suitable initial candidate for delineating a constructive multilateral solution, beginning with bilateral and regional accords. This commentary sets out a “way of seeing” the problem in such manner as emphasizes the diplomatic imperative and the extent to which migration policy has become, in a very material fashion, a matter of foreign affairs.

Image: A view of the US border fence, covered in concertina wire, separating the US and Mexico, at the outskirts of Nogales, Arizona, on February 9, 2019. (Photo by  ARIANA DREHSLER/AFP/Getty Images)