In recent years, a series of startling global developments has provoked a new round of thinking among students of international affairs about the international order and America’s place in it. China’s staggering economic growth and military buildup, India’s dramatic economic turnaround, Russia’s swelling oil wealth and resurgent autocracy, Iran’s petro-dollar-fueled and Islamic-inspired sponsorship of transnational terror and pursuit of nuclear weapons, and the worldwide war against jihadism have conspired to reinvigorate our thinking about the way America can, and should, act abroad. In “The Post-American World” (W.W. Norton, 292 pages, $25.95), his welcome contribution to the debate, Fareed Zakaria, editor of Newsweek International, deftly avoids the extremes of declinism and triumphalism, though his provocative opening lines give a fair indication of the temptation to which he is vulnerable: “This is a book not about the decline of America, but rather about the rise of everyone else.”

That rise, Mr. Zakaria vividly illustrates, has been nothing short of spectacular. Where not long ago the grandest human undertakings were predominantly American, today the world’s tallest buildings stand in Taipei and Dubai, the world’s richest man was Mexican until this spring, when Warren Buffet passed him, the world’s largest factories are in China, the world’s biggest movie industry is in India, and nine out of 10 of the world’s biggest shopping malls are not in America.

But these are merely tokens of a fundamental change. We have been witnesses to “the birth of a truly global order” in which countries from all regions increasingly participate in international commerce and trade, and their citizens operate not as masters or dependents but as producers and consumers, manufacturers and merchants, financiers and entrepreneurs. This global order, Mr. Zakaria observes, is notable not only for its diffusion of power among states but also for its diffusion of power to non-state actors, including international institutions, nongovernmental organizations, and multinational corporations.

Indeed, the emergence of a truly global economy is, in Mr. Zakaria’s judgment, the dominant fact of international politics today. The emergence was decisively advanced by America’s victory in the Cold War, which made free-market capitalism the only viable economic system, and thereby unleashed the flow of capital across borders and permitted a vast extension of the international order. Revolutions in transportation and telecommunications amplified the effects, dramatically increasing the volume and pace of the international flow of goods and information.

With new wealth, however, has come a new surge of disruptive nationalist passions for honor and influence. Nor is nationalism the only challenge generated by globalization to international order. Globalization and Americanization may not be equivalent, but whatever globalization touches bears the mark of American culture and Western opinions about individual freedom and human equality. By weakening traditional practices and established hierarchies, the spread of democratic mores and mass cultures brings instability. At the same time, beneath the trend toward homogenization of culture and politics, Mr. Zakaria discerns a complex mixing of the local and the global.

This complex mixing is the key to understanding China and India, the most important of the rising powers. China has a population of 1.3 billion — more than four times the size of America’s — and an economy that has been growing at a mind-boggling and record-breaking 9% a year for nearly three decades. By combining autocratic rule with capitalism, China has managed a feat, at least for the time being, that many thought impossible, and which has ominous implications. For if in China political liberalization does not follow economic liberalization — as it has with remarkable consistency around the globe — then it is reasonable to fear that at home and abroad, Beijing will pursue its interests and exercise its growing muscle in ways that are at best indifferent to the claims of freedom and equality.

As the world’s second-fastest-growing economy and home to 1.1 billion, India, too, has achieved a new prominence on the world’s stage. It is a more natural ally to America: Its elites speak English as a native tongue; it is a multiethnic and multireligious democracy; it possesses a genuine and robust private sector, and its leading religion, Hinduism, encourages toleration by emphasizing the multiplicity and diversity of gods. For India, the question is whether its bustling economy and society will be able to overcome its government’s sluggishness and corruption.

As for America, its challenge is to learn to increasingly share power not only with Beijing and New Delhi but with a host of rising and diverse players. But this sharing, Mr. Zakaria argues, will come from a position of pre-eminence. America still boasts the most dynamic and competitive economy in the world. It leads the world in higher education and its schools still excel at teaching students to think critically and creatively. Whereas declining fertility rates in Europe, Japan, Taiwan, Korea, Hong Kong, and China are resulting in declining populations, America’s population is growing, despite declining birth rates, because of immigration. And when disputes arise and wars break out, nations around the world still look to America to be the world’s “honest broker.”

To retain its role as honest broker, Mr. Zakaria stresses, America must adapt. Despite the waning of its influence, it will remain for decades to come the world’s sole superpower, and so it will have to take the lead in easing international tensions created by the new nationalism and in advancing integration into the international system. To meet this challenge, Mr. Zakaria admonishes, conservatives in America will have to discipline their arrogant, go-it-alone proclivities and progressives will need to overcome their shortsighted isolationist tendencies.

Moreover, it has become more urgent than ever for Americans to dedicate themselves to studying the languages and cultures of rivals and allies. Such study is not only necessary for the purposes of adjudicating the complex controversies that are the routine stuff of contemporary foreign affairs; it is also urgent if America wishes to cooperate and compete effectively in a world in which, out of necessity, foreigners know English in addition to their own language. But most of all, Mr. Zakaria concludes, we must understand that the source of our strength lies in preserving our commitment to a government and a society at home that together secure individual freedom, cultivate toleration, and reward productivity and innovation.

Occasionally, Mr. Zakaria’s analysis strikes a discordant note. He portrays Iraq as a catastrophe, though the jury is still out. He argues that the threat of jihadism has been grossly exaggerated without adequately addressing the jihadists’ fanaticism, the mobility of their transnational terrorist networks, the porousness of Western societies, or the proliferation and destructiveness of weapons of mass destruction. He seeks to show that anti-Americanism has become a major problem, particularly after the invasion of Iraq, by quoting a few foreign diplomats. Yet he overlooks that all Arab Gulf countries cooperated with America in the war and have continued to cooperate throughout the painful reconstruction; in recent years, Japan, Canada, France, and Germany have elected pro-American governments, and, as he observes elsewhere, India, home to one-sixth of the world’s population, has a 71% favorable view of America, second only to America’s own 83% favorable view. And he understates the extent to which America, the only power that can project power promptly and effectively around the globe, needs to serve not only as the world’s honest broker but also as its upright sheriff.

On the larger question, though, Mr. Zakaria is illuminating and right: The “rise of the rest” represents the triumph of the liberal international order that America has championed in war and peace, and which, as the world’s lone superpower, it has a special interest and responsibility in maintaining and extending.

Mr. Berkowitz is the Tad and Dianne Taube Senior Fellow at the Hoover Institution, Stanford University, and teaches at George Mason University School of Law. He is the author of “Virtue and the Making of Modern Liberalism,” and “Nietzsche: The Ethics of an Immoralist.”