The greater challenge to the international order may lie in the tensions within, rather than between, states, as James suggests. The United States holds a predominance of power not seen since imperial Rome, a development that profoundly changed the international system and underpins post-1989 globalization. Like Rome, however, the American-led global order faces problems created primarily by its own internal dynamics. What James calls the "Roman dilemma" arises from the fact that the way in which peaceful commerce produces a stable, prosperous and integrated global order also creates undercurrents of conflict. A vicious circle thus leads the liberal, commercial world order to subvert and destroy itself.

James warns that the current system's excessive reliance on rules, rather than consensus, threatens its enduring legitimacy. Without legitimacy based on shared assumptions, the costs of economic change spark political backlash. The internal disturbance in a far-flung country can reverberate dramatically, given the new proximities and connections of globalization--as witnessed on September 11. Understanding the problem requires a long view that takes into account historical examples where systems decayed from within.

Internal problems from 1760 to 1825 exposed fault lines within Britain's North Atlantic world, the ancien régime of France and the empire of Habsburg Spain. Reform led to still more pressures and fragmentation. The beginnings of what historians describe as the age of Atlantic revolutions provided the backdrop to Edward Gibbon's Decline and Fall of the Roman Empire and Adam Smith's Wealth of Nations. Both works explored the internal conditions that eroded great accumulations of power, and their appearance in 1776 coincided with the crisis of the American Revolution. Like many authors, Gibbon and Smith wrote with an eye on the headlines of their day, and James discerns in their work an inquiry into the relationship between social order and rules that guides his erudite discussion.

American military supremacy and a global economic order that generates unparalleled prosperity limit the scope for confrontation among great powers. An open break would impose too many costs. Instead, leaders confine themselves to heated rhetoric and "gesture politics", allowing them to grandstand but avert conflict. In earlier periods, such posturing might be the prologue to war, as with the Ems dispatch that produced the Franco-Prussian war in 1870, but they now generate little more than domestic applause. The deeper problem lies in the discontent of those groups that believe themselves victims of economic change.

James explored at length the historical pattern whereby economic dislocation produces efforts to insulate powerful domestic constituencies in The End of Globalization: Lessons from the Great Depression (2000), and here he describes the tensions it creates with greater attention to culture and an eye to current policy concerns. Demands for greater regulation and protectionist measures have created an increasingly dense network of rules that limits flexibility. Post-1945 liberal internationalism was propelled by American efforts and served American interests, but, as John Ikenberry has pointed out, the constraints it has imposed over the past few decades have led Americans to turn away from the system they created. James sees this as part of a much wider pattern that challenges the legitimacy of the current order.

Can the system hold? The United States serves as the linchpin of global economic stability, but budget and trade deficits make its position more precarious than during the immediate post-1945 decades of unchallenged supremacy. Even in the 1960s, Washington aroused Charles de Gaulle's ire by using the dollar's position as a reserve currency to sustain American spending with other people's money.

James considers American dynamism today as contingent on the nation's continued ability to borrow and draw investment. While fiscal problems threaten the sustained growth the United States needs to maintain capital inflows, other countries have also seen their fiscal position deteriorate at the millennium. Greater integration of the global economy increases the potential for shocks to echo through the system. James claims that financial volatility tends to fuel resistance to globalization among those less able to weather the storm.

Just as globalization transmits pressures through the economic system, so the politics of empire can exaggerate the impact of circumstances along the periphery. Unrest in outlying regions, seemingly of little significance, can generate threats to the metropole, as with terrorist attacks. Also, James argues that when great powers select one central focus, others are neglected. Vietnam in the late 1960s and the Iranian hostage crisis are examples. And the current nation-building project in Iraq provides an uncertain basis on which to stake American prestige. Direct intervention can weaken the legitimacy of empire, sparking further challenge and undermining support at home. Political cycles, like economic ones, can be virtuous or vicious, quickly transforming stability-building measures into destabilizing missteps.

Neither James nor Layne provide specific answers to the problems of global order, and James makes no pretense of attempting to do so. Both authors point to the importance of pragmatism. The practice of transforming sound principles into an ideology and then testing it to the breaking point always ends badly. The inevitability of change underlines the need for continuity and the dangers of promoting instability. Force only works in carefully chosen situations. More importantly, policymakers should prevent crises from reaching that critical point demanding intervention.

American policy succeeded remarkably in creating structures to contain or manage conflict after 1945, but little has been done to adapt international organizations or alliances for new circumstances. Neither grand projects nor strategies seem likely to gain sufficient traction, now that the idealistic moment of the 1990s has passed. Instead, it will take careful work along the margins of diplomacy to strengthen institutions sapped by apathy or overreaching.