No informed observer of politics in the United States or Europe today could fail to notice that cross-border movements—whether of goods, ideas, or people—are of tremendous significance in contemporary life. What might be thought of as innocuous movements across borders, and that once were largely regarded as such, are so no longer. We are therefore in Martin Schain’s debt for his thoughtful, informative analysis of the place of the border in contemporary European and American life.

Borders are places where one departs one order—whether territorial, organizational (e.g., citizenship or labor market), or conceptual (e.g., class or race)—and enters another. Schain is chiefly concerned with old-fashioned territorial borders. Yet he reminds us that the modern border and the frontier are by no means necessarily in the same place. The point of transition from one territorial order to another may, in fact, be found well inside the international boundary (the line on a map) if one enters by air. Alternatively, the border may effectively be in the would-be traveler’s country of origin, where consular or other officials of the destination country may determine whether he or she will be permitted to proceed from one order to another.

Borders, as Schain again helpfully notes, vary in character as well. Some are soft, whereas others are hard, and these qualifiers themselves may vary according to time and place. In the United States, state borders are “hard” when it comes to defining crimes, which may become federalized if a miscreant crosses state borders in the commission of the crime. Yet state borders have become very soft from the point of view of freedom of movement. After the Great Depression, when California sought to restrict the entry of “Okies” fleeing poverty in the Dust Bowl, the Supreme Court struck down a state’s authority to deny entry to indigent nonresidents, effectively guaranteeing the right to move about the entire country. In “Schengenland,” the European region governed for purposes of movement by the Schengen Agreement, a similar process has taken place. Whereas individual states once controlled entry, and freedom of movement was limited to the interior of that state, admission into the Schengen area now also entails freedom of movement throughout the numerous countries comprising the Schengen zone. Freedom of movement for EU citizens is also a core right of European citizenship and is taken very seriously as a matter of law. From the point of view of freedom of movement within Schengenland and in the United States, the exterior border is the one that really matters. It has been policed accordingly in recent years.

But Schain shows by way of a comparative analysis that this is not the same as saying the external border is policed in the same way in the two contexts. The external borders of the Schengen area (not of Europe per se, because a number of countries are not signatories to the accord) face would-be immigration primarily by those arriving on planes, whereas those seeking to enter at land and sea borders are more likely asylum seekers. In contrast, would-be immigrants tend to try to enter the United States at a land border, principally the southern border. The number of asylum seekers at the southern border has grown recently, however, because of the rise in violence and criminality in Central America.

A key organizing notion of Schain’s book is the “liberal democratic paradox” articulated by Matthew Gibney and Randall Hansen in Deportation and the Liberal State (2003), which holds that post–World War II human rights norms make it difficult to exclude would-be entrants, but that these norms also conflict with the preferences of democratic publics who tend to be unenthusiastic about immigration. This is especially true in Europe because of the large numbers who claim asylum at the land and sea borders as compared to the United States. In the United States, by contrast, the number of refugees—who are vetted outside the US borders and are typically recommended for acceptance by the United Nations High Commissioner for Refugees—is determined by law. Of necessity, however, asylum seekers tend to be in the country illegally, at least until a determination is made in their case. Meanwhile, immigration into the United States is governed by various laws stipulating how many people may enter in a given year and leans, as in Europe, toward promoting family unification.

Despite Schain’s stress on hardening borders, he does not endorse the view that recent trends amount to the creation of a “fortress Europe” or “fortress America.” Compared to earlier, more easygoing times, the preoccupation with borders has intensified in both Europe and the United States. Publics in both places have indicated a growing disquiet with illegal immigration, even if this is less of a problem in Europe than it is in the United States. Yet even with all the harsh anti-immigrant talk of Donald Trump and Viktor Orbán, Schain shows that the numbers of immigrants in Europe and the United States have drifted upward in recent years, and publics indicate growing support for legal immigration.

One oddity of The Border, given its title, is that the book has very little to say about what happens at the border itself, as opposed to what happens because of the existence of borders. As a result of Schain’s effort to understand how trade and immigration are related to each other, for example, we learn much valuable information about the vicissitudes of truck haulage over time and its relationship to the border-crossing movements of people. But little is said about people’s experiences of the border, how they are treated by border officials, and the like. One imagines that those who arrive at the borders of the United States and of Schengenland are dealt with differently depending on their race, language, dress, and the like; yet to what extent is that the case? This would seem particularly important in an era where immigrant children have been separated from their parents at the southern border in the United States as a matter of national policy under the Trump administration, for example.

We also learn little about tourism, presumably the main reason that people cross borders today. This seems an important lacuna even in a book mainly focused on immigration policy, because perhaps one-third to one-half of undocumented immigrants are visa overstayers, not persons who have entered a country illegally. Schain is focused more or less exclusively on the consequences of borders for would-be immigrants, whether they arrive after having gone through the legally stipulated procedures for immigrants or refugees, are “undocumented,” or are in the process of claiming asylum (contrary to expectation, usually a less successful route to immigration than the “normal” path). In short, the book is really about the topic of its subtitle: the policy and politics of immigration in Europe and the United States.

Notwithstanding these quibbles, The Border provides a data-rich picture of the way the contemporary borders of the United States and Europe work to filter the entry of people. Schain shows that, although we are very far from “losing control,” as some have suggested, neither have the borders become hardened to the point of near-closure. For such a phenomenon, one would have to look at a country such as Japan, long an island fortress seeking to maintain its ethnic purity. European and American external borders have hardened because politicians have exploited the ethnic diversity of immigrant populations to reap votes, often from those fearful of such diversity. One result has been Brexit, which was largely a response to British fears that the country had lost control of its borders. As Martin Schain shows in great detail, borders matter in contemporary politics.