STRATEGY 1. The Return of Marco Polo''s World and the U.S. Military Response As Europe Disappears, Eurasia Coheres. The supercontinent is becoming one fluid, comprehensible unit of trade and conflict, as the Westphalian system of states weakens and older, imperial legacies--Russian, Chinese, Iranian, Turkish--become paramount. Every crisis from Central Europe to the ethnic-Han Chinese heartland is now interlinked. There is one singular battle space. What follows is an historical and geographical guide to it.

The Dispersion of the West Never before in history did Western civilization reach such a point of geopolitical concision and raw power as during the Cold War and its immediate aftermath. For well over half a century, the North Atlantic Treaty Organization (NATO) condensed a millennia-long tradition of political and moral values--the West, in shorthand--into a robust military alliance. NATO was a cultural phenomenon before it was anything. Its spiritual roots reach back to the philosophical and administrative legacies of Greece and Rome, to the emergence of Christendom in the early Middle Ages, and to the Enlightenment in the seventeenth and eighteenth centuries--from which the ideas of the American Revolution emerged. Of course, key nations of the West fought as an alliance in the First and Second World Wars, and those emergency contingencies constituted forerunners to NATO''s more secure and elaborate structures. Such structures, in turn, were buttressed by a continent-wide economic system, culminating in the European Union (EU). The EU gave both political support and quotidian substance to the values inherent in NATO--those values being, generally, the rule of law over arbitrary fiat, legal states over ethnic nations, and the protection of the individual no matter his race or religion. Democracy, after all, is less about elections than about impartial institutions.

The end of the Long European War, 1914-89, saw those values reign triumphant, as communism was finally defeated and NATO and the EU extended their systems throughout Central and Eastern Europe, from the Baltic Sea in the north to the Black Sea in the south. And it categorically was a long European war, as wartime deprivations, political and economic, existed in Soviet satellite states until 1989, when the West triumphed over Europe''s second totalitarian system, just as it did over the first in 1945. Civilizations often prosper in opposition to others. Just as Christendom achieved form and substance in opposition to Islam after the latter''s conquest of North Africa and the Levant in the seventh and eighth centuries, the West forged a definitive geopolitical paradigm in opposition to Nazi Germany and Soviet Russia. And because the aftershocks of the Long European War extended to the very end of the twentieth century, with the dissolution of Yugoslavia and chaos inside Russia, NATO and the EU remained as relevant as ever, with NATO demonstrating its expeditionary capability in the case of Yugoslavia, and the EU building inroads into the former Warsaw Pact to take advantage of Russia''s infirmity. This era was called the Post Cold War--that is, it was defined in terms of what came before it and what still continued to influence it. The Long European War, which lasted three-quarters of a century, influences events still, and constitutes my entry point for describing a new world far beyond Europe that the U.S.

military now must grapple with. And because Europe''s current predicament constitutes an introduction to that new world, I begin with it. It was the monumental devastation of two world wars that led European elites, beginning in the late 1940s, to reject the past altogether, with all of its inherent cultural and ethnic divisions. Only the abstract ideals of the Enlightenment were preserved, which in turn led to political engineering and economic experimentation, so that the specific moral response to the human suffering of 1914-18 and 1939-45 was the establishment of generous social-welfare states, which meant highly regulated economies. As for the national-political conflicts that gave birth to the two world wars, they would not be repeated because, in addition to other aspects of supranational cooperation, European elites imposed a single monetary unit on much of the continent. Except in the most disciplined northern European societies, however, those social-welfare states have proven unaffordable, just as the single currency has caused the weaker economies of southern Europe to pile up massive debt. Alas, the post-World War II attempt at moral redemption has led over time to an intractable form of economic and political hell. The irony deepens.

Europe''s dull and happy decades in the second half of the twentieth century were partially born of its demographic separation from the Muslim Middle East. This, too, was a product of the Cold War phase of the Long European War, when totalitarian prison-states in such places as Libya, Syria, and Iraq were propped up for decades by Soviet advice and support, and afterward took on a life of their own. For a long time Europe was lucky in this regard: It could reject power politics and preach human rights precisely because tens of millions of Muslims nearby were being denied human rights, and with them the freedom of movement. But those Muslim prison-states have all but collapsed (either on their own or by outside interference), unleashing a tide of refugees into debt-ridden and economically stagnant European societies. Europe now fractures from within as reactionary populism takes hold, and new borders go up throughout the continent to prevent the movement of Muslim refugees from one country to another. Meanwhile, Europe dissolves from without, as it is reunited with the destiny of Afro-Eurasia as a whole. All this follows naturally from geography and history. For centuries in early and middle antiquity, Europe meant the entire Mediterranean Basin, or Mare Nostrum ("Our Sea") as the Romans famously called it, which included North Africa until the Arab invasion of Late Antiquity.

This underlying reality never actually went away: In the mid-twentieth century, the French geographer Fernand Braudel intimated that Europe''s real southern border was not Italy or Greece, but the Sahara Desert, where caravans of migrants now assemble for the journey north. Europe, at least in the way that we have known it, has begun to vanish. And with it the West itself--at least as a sharply defined geopolitical force--also loses substantial definition. Of course, the West as a civilizational concept has been in crisis for quite some time. The very obvious fact that courses in Western civilization are increasingly rare and controversial on most college campuses in the United States indicates the effect of multiculturalism in a world of intensified cosmopolitan interactions. Noting how Rome only partially inherited the ideals of Greece, and how the Middle Ages virtually lost the ideals of Rome, the nineteenth-century liberal Russian intellectual Alexander Herzen observed that "[m]odern Western thought will pass into history and be incorporated in it, will have its influence and its place, just as our body will pass into the composition of grass, of sheep, of cutlets, and of men. We do not like that kind of immortality, but what is to be done about it?" Indeed, Western civilization is not being destroyed; rather, it is being diluted and dispersed. After all, how exactly does one define globalization? Beyond the breakdown of economic borders, it is the worldwide adoption of the American form of capitalism and management practices that, merging with the advance of human rights (another Western concept), has allowed for the most eclectic forms of cultural combinations, wearing down in turn the historical division between East and West.

Having won the Long European War, the West, rather than go on to conquer the rest of the world, is now beginning to lose itself in what Reinhold Niebuhr called "a vast web of history." The decomposition that Herzen spoke of has begun. A New Strategic Geography As Europe disappears, Eurasia coheres. I do not mean to say that Eurasia is becoming unified, or even stable in the manner that Europe was during the Cold War and the Post Cold War--only that the interactions of globalization, technology, and geopolitics, with each reinforcing the other, are leading the Eurasian supercontinent to become, analytically speaking, one fluid and comprehensible unit. Eurasia simply has meaning in the way that it didn''t use to. Moreover, because of the reunification of the Mediterranean Basin, evinced by refugees from North Africa and the Levant flooding Europe, and because of dramatically increased interactions across the Indian Ocean from Indochina to East Africa, we may now speak of Afro-Eurasia in one breath. The term "World-Island," early-twentieth-century British geographer Halford Mackinder''s phrase for Eurasia joined with Africa, is no longer premature. The slowly vanishing West abets this development by depositing its seeds of unity into an emerging global culture that spans continents.

Further encouraging this process is the erosion of distance by way of technology: new roads, bridges, ports, airplanes, massive container ships, and fiber-optic cables. It is important, though, to realize that all this constitutes only one layer of what is happening, for there are more troubling changes, too. Precisely because religion and culture are being weakened by globalization, they have to be reinvented in more severe, monochromatic, and ideological form by way of the communications revolution. Witness Boko Haram and the Islamic State, which do not represent Islam per se, but Islam igniting with.