As the Cold War came to an end, the political scientist Francis Fukuyama heralded the "End of History." Decades earlier, the sociologist Daniel Bell had predicted the "End of Ideology." While we wait for these grand visions to be universalized in practice, we can anticipate a change that, although more mundane, is more likely to occur sooner: the end of alliances. Military alliances, multilateral and bilateral, have been central to the diplomacy and national security strategy of the United States for more than 50 years -- so much so that most Americans will find it hard to imagine a world without them. But such a world is coming, and as with all big changes, it will bring both new opportunities and new vulnerabilities.

Yet the United States is hardly unfamiliar with such a world. In fact, the Cold War era in which such alliances were the pillars of American strategy was an exception and a stark departure for a country that has traditionally been chary of long-term military commitments. The aversion to binding military ties with other countries was true from the outset (the 1778 alliance with France being the exception that proves the rule); the young American republic arose determined to blaze a new trail and regarded alliances with distaste -- as pathways to debilitating entanglements and entrapment in the sordid politics of (to quote our current secretary of defense) "old Europe." This sentiment ran through George Washington's Farewell Address (as well as Thomas Jefferson's own subsequent warning against "entangling alliances") and defined America's worldview for some 150 years. Conveniently, the physical separation offered by two oceans enabled idealism and pragmatism to blend in an appealing design.

As the Industrial Revolution created weapons and modes of transportation that extended the reach and lethality of military threats, Americans were forced to reconsider the utility of alliances. And so we entered into them to fight the two World Wars -- although eagerly discarding them after World War I, as if they were strange and illfitting clothes. The retrenchment could not be repeated after World War II; once Germany and Japan were defeated, our erstwhile Soviet partner quickly became our new security problem, and we decided we needed long-term allies to help deal with it. Mindful of the lessons of the interwar years, American strategists also feared that disorder would result from an abrupt departure by the United States from Europe. They believed, furthermore, that the balance of forces would tilt sharply against the United States if Soviet influence, let alone control, were to extend to Western Europe and Japan, which, despite their devastation by war, were expected to emerge again as centers of wealth and industry.1

Western Europe, for its part, welcomed American protection. World War II had been another sobering lesson about the perils of not counterbalancing German power. An American military presence on the continent -- permanent, substantial, visible, and codified by treaty -- was, therefore, reassuring. These were the circumstances that produced the North Atlantic Treaty Organization (NATO), whose purpose Lord Ismay, its first secretary general, famously characterized as "keeping the Russians out, the Germans down, and the Americans in."

NATO proved to be a harbinger of a wider transformation -- one that would have global ramifications -- in the theory and practice of American statecraft. The logic that gave rise to the Atlantic alliance produced an array of other military pacts that spanned the globe. The United States did not, therefore, merely shed its animus toward alliances; it set about forming them with the fervor of a new convert.

The zeal produced a chain of alliances that included NATO; the Southeast Asia Treaty Organization (SEATO); ANZUS, our partnership with Australia and New Zealand; and bilateral treaties with Japan and South Korea. The Central Treaty Organization (CENTO) -- formed by Britain, Iran, Turkey, Pakistan, and (until 1958, when its monarchy was overthrown) Iraq -- benefited from our blessing, though not our participation.2

"Containment," America's strategy during the Cold War, yielded what is arguably its greatest foreign policy triumph -- the collapse of the Soviet-led communist system -- and it rested on this network of anticommunist alliances planted around the Soviet Union's periphery. The ubiquity of alliances assembled or approved of by Washington during the Cold War prompted observers to describe this phase of American foreign policy as "pactomania."

Since the Cold War lasted for nearly half a century, most Americans cannot remember a time when alliances were not an essential component in our strategic toolkit. The demise of this familiar institution will therefore necessitate big changes in the ways we think about, and act in, the world. The changes are unlikely to be welcomed -- perhaps even acknowledged, until the evidence becomes overwhelming -- by academic experts and bureaucracies "specializing" in national security issues. Their theories, policy prescriptions, reputations, influence, and rewards have, for decades, derived from this earlier, more familiar world. The prospect of entering into unknown terrain can hardly be welcome. Yet alliances have always been contextual and contingent. Pageantry and proclamations accompany their creation, and permanent interests and eternal principles are invoked hopefully, but change over time eventually corrodes such institutions, which ultimately are rooted in particular historical circumstances.

The transience of alliances -- think of SEATO and CENTO, for example -- is worth remembering as the debate about the utility of our Cold War partnerships gains momentum. This debate is still at an early stage, and those who question the rationale for maintaining our current alliances in a post