Over two decades ago, Yale historian Paul Kennedy’s book The Rise and Fall of Great Powers rocketed up the bestseller list, where it remained for nearly a year. As Americans sought to understand a pivotal moment of dramatic change, the massive tome placed the country’s challenge in the context of 500 years of history. Although the Cold War was ending and the United States had reason to feel triumphant, Kennedy warned of the “enduring fact” that the “sum total of the United States’ global interests and obligations is nowadays far larger than the country’s power to defend them all simultaneously.” With Germany and Japan seemingly bound for economic dominance, the prevailing public mood was one of deep pessimism about America’s ability to withstand the crosswinds of global change. Kennedy’s book appeared to confirm the worry that the United States, like Spain, France, and Britain before it, was a great power in twilight.

Of course, the following years were not marked by American decline, but by an amazing period of global dominance–what foreign policy wonks called “unipolarity” or “primacy.” During the 1990s and the early years of the twenty-first century, the U.S. economy boomed, its military capabilities increased, and its political influence reigned. Many around the world complained about what the French called America’s “hyperpower,” while U.S. policymakers and pundits were concerned not about others’ relative strength, but their weakness. They found the Europeans too anemic to be reliable partners, while they fretted over teetering economies from Mexico to South Korea. And rather than fearing the Russian bear, experts worried about the country’s implosion. The lone superpower appeared invulnerable.

Those years now feel distant. Although by any measure of power (economic and military might, political weight) the United States is still dominant, there is again a growing sense that its time is up. As a result of the overreaching policies of the George W. Bush Administration and the changes fueled by economic and technological globalization, America is strategically exhausted and, as the New America Foundation’s Parag Khanna argues in his book The Second World, its global position is like a stretched rubber band that could snap into decline very quickly.

Like Kennedy, Khanna–and Newsweek’s Fareed Zakaria, in his new book The Post-American World–set out to tell the story of how huge global trends are diluting America’s power and eroding its influence. Both authors are perceptive observers steeped in history, and they have much to offer through good old-fashioned reporting and vivid storytelling. By exploring the political and economic transformations underway in places like China, India, and Europe, these books provide a valuable window into the present and future of global politics. But Khanna and Zakaria do more than look out at the world; they also hold a mirror up to America. To a significant degree, there’s reason not to like what they see.

And yet despite the abundant similarities between the two books, progressive policymakers would do well to understand their differences. Ultimately, whereas Khanna is committed to a declinist view of the American future, Zakaria presents a workable framework for getting the country out of its rut and back on a path to global leadership. It is this difference that has been a fundamental divide among the center left, and as we envision a post-Bush foreign policy, it threatens to reemerge.

Much of what Khanna and Zakaria argue will be familiar to Thomas Friedman fans. As countries modernize and become more economically and technologically sophisticated, the barriers to entering global competition are becoming far less steep. Individuals have become empowered to do both good and bad, and the battle for ideas and innovation is fierce. Yet while both authors agree with Friedman that the world is getting “flatter,” they do not see it turning into one integrated whole. Instead, globalization is causing cleavages and increasing rivalries, with new power centers emerging to challenge the United States. Globalization may be the dominant trend, but geopolitics lives on.

For Khanna, the world’s map is being redrawn among three twenty-first-century superpowers: the United States, China, and the European Union. He asserts that each represents its own empire, using its own distinct diplomatic style–America’s emphasis on coalitions, Europe’s on consensus, and China’s on consultation–to maneuver and try to dominate the global chessboard. The most important arena for Khanna is what he describes as the “second world” states such as Turkey, Brazil, and Iran, those that have a hybrid of globalization’s modernity but are still saddled with third world problems like extreme poverty and deep corruption. It is here, Khanna asserts, where the fate of geopolitics will be decided. “The future of the second world hinges on how it relates to the three superpowers,” he argues, “and the future of the superpowers depends on how they manage the second world.”

The bulk of Khanna’s book is a fast-moving tour of the second world, and this is where it shines. In the tradition of the great British historian Arnold Toynbee–whose 1958 book, East to West: A Journey Round the World, Khanna seeks to emulate–and current writers like Robert Kaplan, this is a serious book written by an author in motion. Khanna uses his exhaustive travels (by my count, he visited over 40 countries) not just to describe places few readers have ever been or will ever go but to explore complex global changes with first-hand observations and plenty of local color. From the barrios of Caracas and scenes of whirling dervishes in Turkey to the rugged Hindu Kush and the gleaming glass and steel of Dubai and Shanghai, we get a picture of the second world in all its hopes and contradictions. As a primer on many of the globe’s most important yet distant places, one will find it hard to read this book and not come away enlightened.

Zakaria follows a similar approach in The Post-American World, although with fewer frequent-flier miles and a tighter aperture. His depiction of what he calls the “rise of the rest,” or those emerging powers “entering the Western order but doing so on their own terms,” focuses mainly on the big powerhouses: China and India. Of the two, Zakaria sees China as a more direct challenger to the United States, and he explains how its elites are thinking seriously about how to manage the country’s transformation. Much of what he details will not be new to even casual China watchers, but he does uncover some interesting–and possibly illuminating–nuggets, such as the fact that Albert Speer Jr., the son of Hitler’s infamous architect, is helping redesign Beijing’s streets for the Olympics. He also handles questions about a possible military conflict between the United States and China with welcome sobriety.

Both authors take the same tack in addressing the U.S. politics and its relationship to globalization–namely, that it is highly dysfunctional. They lament the fact that instead of embracing globalization, too many politicians are running from it by demonizing immigration, curbing trade, and neglecting global institutions. This is especially true for conservatives, who have never really been comfortable with globalization. During the 1990s they could barely bring themselves to utter the term, believing that to do so would be tantamount to embracing a kind of Davos one-worldism.

But globalization is not just a problem for conservative politics. Progressives have likewise dabbled in isolationist and protectionist populism. Indeed, anti-free trade politics is again resonating with broad swaths of the liberal electorate. And there is a consistent strain of progressive thinking, within which Khanna’s book clearly falls, which argues that to understand America’s troubles with the globalizing world and its inability to grapple with the rise of second world states and a post-American order, one shouldn’t just point the finger at the U.S. political system, but at America itself. By this argument, the problem is more fundamental than the design of our government’s structures and institutions or the quality of our leaders; the problem is us. Khanna argues that when considering a variety of measures–the widening gap between rich and poor, the relative poor health and obesity of many Americans, rising crime–the United States is “ceasing to be a middle class nation, becoming instead a classic second-world combination of extremes.”

Khanna is correct that in too many domestic arenas, the United States needs urgent reform. Progressives have been making such arguments for years. Yet he greatly diminishes his case by displaying a significant degree of pessimism about, and in some cases outright disdain for, America itself, criticizing everything from the movies we like to the sports we follow. By comparison, he exudes admiration for Europe and its evolving union (although one wonders how he squares his contempt for America’s “wasteful motor sports” with his exalted Europe’s own obsession with fast cars and motorbikes). In his telling, America’s decline is basically irreversible; there’s nothing left for Americans to do but sit back and wait for the fall. That doesn’t offer much for those looking for a way forward.

This is where Zakaria proves far more edifying–and where the significant difference between these two books exists. He does not downplay the challenges the United States faces, but he works hard to remind us that, actually, the news is not all that bad. “It feels like a dangerous world,” he writes. “But it isn’t.” Zakaria makes the important point that despite predictions to the contrary, the global economy has continued to grow, and Al Qaeda central (led by Osama bin Laden and his cohorts) has not been able to pull off a successful spectacular attack against the United States since September 11. Of course the globe is changing, and of course the United States will not remain as dominant as it has been during the last 20 years. But the important point, he argues, is that the world is moving toward the values and structures that the country espouses and, in turn, that benefit its interests: “As long as we keep the forces of modernization, global interaction, and trade growing, good governance, human rights, and democracy all move forward.”

Nevertheless, even if the global order is becoming “post-American,” the world still needs the United States. Zakaria notes that for all its recent troubles, the country still maintains deeper relations with more of the world than any other global power, and it is still relied upon to help resolve disputes and to solve problems. As Madeleine Albright argued over a decade ago, the United States remains the “indispensable nation.”

After the Cold War, prominent conservatives like Jeane Kirkpatrick argued exactly the opposite: that the United States could become a “normal” country, husbanding its resources by playing a lesser role on the global stage and being satisfied as one of many powers. But the Clinton Administration believed correctly that despite the temptation to look inward, the United States had unique global responsibilities. Such views were not uncontroversial at the time, and, as countless books and political speeches attest, they remain a divisive issue today. Conservatives are again being tempted by nativist isolationism, while some on the left, like Anatol Lieven, reject any talk of American exemplarism as the kind of chest-thumping one might see from a rogue state. Yet the idea of America as indispensable is not a statement of arrogance. Rather, it is recognition of the fact that there are no major problems in the world today–from global warming to global terrorism–that can be solved without the United States’ active participation.

The tragedy is that just as the world is moving toward an embrace of democracy and free markets at home and liberal internationalist values abroad, the Bush Administration’s policies have moved us in precisely the wrong direction. This is a fashionable argument nowadays–critiques of Bush’s foreign policy have been a major boon to the publishing industry–and Zakaria makes it extremely well. He deplores the way Republican politicians have stoked fear to fuel their agendas. He ably demonstrates how the “war on terror” framework has failed as the core concept for American policy, undermining our freedoms at home, but also hurting the United States abroad by tarnishing the most essential and unique ingredient of its power: its legitimacy. It is up to progressives not to react by withdrawing from the world, but to make sure the United States has the legitimacy to meet these needs in the future.

To be sure, creating and maintaining legitimacy is not an easy thing to do. Because America’s power remains dominant, and power tends to raise suspicions, there will always be those who question U.S. intentions. But one crucial advantage the United States has over others is that because of its history, ideals, and political system, it is not just any country. It has a fundamental legitimacy. Because of their authoritarian nature, states like China and Russia will never be able to earn the kind of trust and support that the United States can garner. They will never lead by consent internationally, because they do not have a tradition of doing so domestically. No one is clamoring for a world dominated by Russia or China. Millions, though, do still find hope in the United States, even if they question its current direction.

How, then, does the country earn back legitimacy? A start would be to remove major irritants, such as the detainee facility at Guantanamo Bay and continuing opposition to the Geneva Conventions, which have caused many to question America’s commitment to its own core values. These may sound like liberal debating points, but as Khanna and Zakaria show, these hypocritical positions are the new image of U.S. foreign policy among the global elite and masses alike and are hurting our effort to sway both.

Another important step would be for the United States to become more, as Zakaria puts it, “Bismarckian” playing the role of a global honest broker that works to set the agenda, define the issues, create coalitions, and forge solutions building off the growing global consensus behind democracy and liberal free markets. But the United States should not seek cooperation for its own sake, or become captive to unrealistic expectations about multilateralism. Even the most capable global institutions have limits, especially those like the U.N. Security Council, which is increasing split between liberal democracies and autocratic powers such as China and Russia. That said, if the United States took global cooperation seriously again–by trying to make existing institutions even more effective and perhaps building new ones–it would go a long way to restoring American legitimacy.

This is not something that only liberals understand. Increasingly, internationalist conservatives have come to admit the importance of the United States leading by consent. That’s why some influential conservative thinkers like Robert Kagan and leaders like Senator John McCain have come to champion such ideas as an “alliance” or “league” of democracies in which the United States could work with other liberal democratic countries. This could be a formal institution, or an informal consultative process. In either case, democracies would come together to discuss common problems, from transitional issues like climate change and nuclear proliferation to collective security threats. Eventually, it could be a mechanism through which democratic nations could combine their political, economic, and military resources.

Although similar ideas have been championed by liberals for years, some on the left today fear that such an alliance would be a Trojan horse to further undermine the United Nations. On the contrary, it would provide a needed supplement to divided forums like the Security Council, and it would bring the United States even closer to those who share its values and goals. It could help bestow legitimacy on action that democracies believe necessary but autocratic nations oppose–intervention in Darfur, for example.

But to take proactive steps such as these, one must believe that America’s decline is not inevitable. It’s true that how this story turns out depends on whether Americans work to understand and adapt to the dramatic global changes that Khanna and Zakaria detail. But just as there is a certain cyclical quality to fears of declinism among policy thinkers and pundits, so exists the possibility of renewal. As Kennedy pointed out two decades ago, despite the rise of other nations and the threat of imminent decline, the United States still remains in a class of its own. The question is how we respond. “Because [the United States] has so much power,” Kennedy wrote, “because it is the linchpin of the western alliance system and the center of the existing global economy, what it does, or does not do, is so much more important than what any of the other powers decides to do.” The fact that so many nations are watching closely to see how America answers those questions shows how indispensable it remains.