In their own international institutions and alliances, they demand strict fidelity to liberal democratic principles. Before opening their doors to new members and providing the vast benefits that membership offers in terms of wealth and security, they demand that nations that want to enter the EU or NATO open up their economies and political systems. When the Georgian president called a state of emergency at the end of 2007, he damaged Georgia's chances of entering NATO and the EU anytime soon. As a result, Georgia may now live precariously in the nether region between Russian autocracy and European liberalism. Eventually, if the democracies turn their backs on Georgia, it may have no choice but to accommodate Moscow.

Again, this competition is not the Cold War redux. It is more like the nineteenth century redux. In the nineteenth century, the absolutist rulers of Russia and Austria shored up fellow autocracies in post-revolutionary France and used force to suppress liberal rebellions in Germany, Poland, Italy, and Spain. Palmerston's Britain used British power to aid liberals on the continent; the United States cheered on liberal revolutions in Hungary and Germany and expressed outrage when Russian troops suppressed liberal forces in Poland. Today Ukraine has already been a battleground between forces supported by the West and forces supported by Russia, and it could well be a battleground again in the future. Georgia could be another. It is worth contemplating what the world would look like, what Europe would look like, if democratic movements in Ukraine and Georgia failed or were forcefully suppressed, and the two nations became autocracies with close ties to Moscow. It is worth considering what the effect would be in East Asia if China used force to quash a democratic system in Taiwan and install a friendlier autocracy in its place.

The global competition between democratic governments and autocratic governments will become a dominant feature of the twenty-first-century world. The great powers are increasingly choosing sides and identifying themselves with one camp or the other. India, which during the Cold War was proudly neutral or even pro-Soviet, has begun to identify itself as part of the democratic West. Japan in recent years has also gone out of its way to position itself as a democratic great power, sharing common values with other Asian democracies but also with non-Asian democracies. For both Japan and India the desire to be part of the democratic world is genuine, but it is also part of a geopolitical calculation--a way of cementing solidarity with other great powers that can be helpful in their strategic competition with autocratic China.

There is no perfect symmetry in international affairs. The twin realities of the present era--great power competition and the contest between democracy and autocracy--will not always produce the same alignments. Democratic India in its geopolitical competition with autocratic China supports the Burmese dictatorship in order to deny Beijing a strategic advantage. India's diplomats enjoy playing the other great powers against each other, sometimes warming to Russia, sometimes to China. Democratic Greece and Cyprus pursue close relations with Russia partly out of cultural solidarity with Eastern Orthodox cousins, but more out of economic interest. The United States has long allied itself with Arab dictatorships for strategic and economic reasons, as well as to successive military rulers in Pakistan. As in the Cold War, strategic and economic considerations, as well as cultural affinities, may often cut against ideology.

But in today's world, a nation's form of government, not its "civilization" or its geographical location, may be the best predictor of its geopolitical alignment. Asian democracies today line up with European democracies against Asian autocracies. Chinese observers see a "V-shaped belt" of pro-American democratic powers "stretching from Northeast to Central Asia." When the navies of India, the United States, Japan, Australia, and Singapore exercised in the Bay of Bengal last year, Chinese and other observers referred to it as the "axis of democracy." Japan's prime minister spoke of an "Asian arc of freedom and prosperity" stretching from Japan to Indonesia to India. Russian officials profess to be "alarmed" that NATO and the Organization for Security and Cooperation in Europe are "reproducing a bloc policy" not unlike that of the Cold War era, but the Russians themselves refer to the Shanghai Cooperation Organization as an "anti-NATO" alliance and a "Warsaw Pact 2." When the Shanghai Cooperation Organization met last year, it brought together five autocracies--China, Russia, Uzbekistan, Kazakhstan, and Tajikistan--as well as Iran. When the ASEAN nations attempted to address the problem of Burma last year, the organization split down the middle, with democratic nations like the Philippines and Indonesia, backed by Japan, seeking to put pressure on Burma, and the autocracies of Vietnam, Cambodia, and Laos, backed by China, seeking to avoid setting a precedent that could come back to haunt them someday.

IV.

The global divisions between the club of autocrats and the axis of democracy have broad implications for the international system. Is it possible any longer to speak of an "international community"? The term implies agreement on international norms of behavior, an international morality, even an international conscience. But today the world's major powers lack such a common understanding. On the large strategic questions, such as whether to intervene or to impose sanctions or to attempt to isolate nations diplomatically, there is no longer an international community to be summoned or led. This was exposed most blatantly in the war over Kosovo, which divided the democratic West from both Russia and China, and from many other nonEuropean autocracies. Today it is apparent on the issues of Darfur, Iran, and Burma.

One would imagine that on such transnational issues as disease, poverty, and climate change the great powers ought to be able to work together despite their diverging interests and worldviews. But even here their differences complicate matters. Disputes between the democracies and China over how and whether to condition aid to poor countries in Africa affect the struggle against poverty. Geopolitical calculations affect international negotiations over the best response to climate change. The Chinese, along with the Indians, believe the advanced industrial nations of the West, having reached their present heights after decades of polluting the air and emitting unconscionable levels of greenhouse gases, now want to deny others the right to grow in the same way. Beijing suspects a western attempt to restrict China's growth and to slow its emergence as a competitive great power. Similarly, the nuclear nonproliferation regime will continue to suffer as the clashing interests of great powers and differing forms of government overwhelm what might otherwise be their common interests in preventing other nations from obtaining nuclear weapons. Russia and China have run interference for Iran. The United States has run interference for India, in order to enlist New Delhi's help in the strategic competition with China.

The demise of the international community is most clearly on display at the U.N. Security Council, which, after a brief post-Cold War awakening, is slipping back into its long coma. The artful diplomacy of France and the tactical caution of China for a while obscured the fact that on most major issues the Security Council has been sharply divided between the autocracies and the democracies, with the latter systematically pressing for sanctions and other punitive actions against autocracies in Iran, North Korea, Sudan, and Burma, and the former just as systematically resisting and attempting to weaken the effect of such actions. This rut will only deepen in the coming years.

Calls for a new "concert" of nations including Russia, China, the United States, Europe, and other great powers are unlikely to be successful. The early-nineteenth-century Concert of Europe operated under the umbrella of a common morality and shared principles of government. It aimed not only at the preservation of a European peace but also, and more important, at the maintenance of a monarchical and aristocratic order against the liberal and radical challenges presented by the French and American revolutions and their echoes in Germany, Italy, and Poland. The concert gradually broke down under the strains of popular nationalism, fueled in part by the rise of revolutionary liberalism. The great power concert that Franklin Roosevelt established at the U.N. Security Council similarly foundered on ideological conflict.

And now, once more, there is little sense of shared morality and common values among the great powers. Instead there is suspicion and growing hostility, and the well-grounded view on the part of the autocracies that the democracies, whatever they say, would welcome their overthrow. Any concert among these states would be built on a shaky foundation likely to collapse at the first serious test.

Can these disagreements be overcome by expanding trade ties and growing economic interdependence in this ever more globalized world? Clearly economic ties can help to check tendencies toward great-power conflict. Chinese leaders avoid confrontation with the United States today both because they could not count on a victory and because they fear the impact on the Chinese economy and, by extension, the stability of their autocratic rule. American, Australian, and Japanese dependence on the Chinese economy makes these nations cautious, too, and the powerful influence of American big business makes American leaders take a more accommodating view of China. In both China and Russia, economic interests are not just national, they are also personal. If the business of Russia is business, as Dmitri Trenin argues, then its leaders should be reluctant to jeopardize their wealth with risky foreign policies.

Yet history has not been kind to the theory that strong trade ties prevent conflict among nations. The United States and China are no more dependent on each other's economies today than were Great Britain and Germany before World War I. And trade relations are not without their own tensions and conflicts. Those between the United States and China are becoming increasingly contentious, with Congress threatening legislation to punish China for perceived inequities in the trade relationship. In both Europe and the United States, concerns about the growing strategic challenge from China are increasingly joined or even outstripped by fears of the growing economic challenge it poses. Fifty-five percent of Germans believe China's economic growth is a "bad thing," up from 38 percent in 2005, a view shared by Americans, Indians, Britons, the French, and even South Koreans. Today 60 percent of South Koreans think China's growing economy is a "bad thing."

The Chinese, meanwhile, may still tolerate pressure to adjust their currency, crack down on piracy, and increase quality standards for their products, as well as all the other hectoring they receive from the United States and Europe. But they are starting to feel that the democratic world is ganging up on them and using these disputes as a way of containing China not only economically but strategically. And there is also the matter of the international scramble for energy resources, which is becoming the primary arena for geopolitical competition. The search for reliable sources of oil and gas shapes China's policies toward Iran, Sudan, Burma, and Central Asia. Russia and the democracies led by the United States compete to build oil and gas pipelines that will provide them leverage and influence, or deny it to their competitors.

Commercial ties alone cannot withstand the forces of national and ideological competition that have now so prominently re-emerged. Trade relations do not take place in a vacuum. They both influence and are influenced by geopolitical and ideological conflicts. Nations are not calculating machines. They have the attributes of the humans who create and live in them, the intangible and immeasurable human qualities of love, hate, ambition, fear, honor, shame, patriotism, ideology, and belief--the things people fight and die for, today as in millennia past.

V.

Nowhere are these human qualities more on display than in the Islamic world, especially the Middle East. The struggle of radical Islamists against the powerful and often impersonal forces of modernization, capitalism, and globalization that they associate with the Judeo-Christian West is the other great conflict in the international system today. It is also the most dramatic refutation of the convergence paradigm, since it is precisely convergence, including the liberal world's conception of "universal values," that the radical Islamists reject.

As a historical phenomenon, the struggle between modernization and Islamic radicalism may ultimately have less impact on international affairs than the struggle among the great powers and between the forces of democracy and autocracy. After all, Islamic resistance to westernization is not a new phenomenon, though it has taken on a new and potentially cataclysmic dimension. In the past, when old and less technologically advanced peoples confronted more advanced cultures, their inadequate weapons reflected their backwardness. Today the more radical proponents of Islamic traditionalism, though they abhor the modern world, are using against it not only the ancient methods of assassination and suicidal attacks, but also modern weapons. The forces of modernization and globalization have inflamed the radical Islamist rebellion and also armed them for the fight.

But it is a lonely and ultimately desperate fight, for in the struggle between traditionalism and modernity, tradition cannot win--even though traditional forces armed with modern weapons, technologies, and ideologies can do horrendous damage. All the world's rich and powerful nations have more or less embraced the economic, technological, and even social aspects of modernization and globalization. All have embraced, with varying degrees of complaint and resistance, the free flow of goods, finances, and services and the intermingling of cultures and lifestyles that characterizes the modern world. Increasingly, their people watch the same television shows, listen to the same music, and go to the same movies. Along with this dominant modern culture, they have accepted--even as they may also deplore--the essential characteristics of a modern ethics and aesthetics. Modernity means, among other things, the sexual as well as political and economic liberation of women; the weakening of church authority and the strengthening of secularism; the existence of what used to be called the counterculture; and the exercise of free expression in the arts (if not in politics), which includes the freedom to commit blasphemy and to lampoon symbols of faith, authority, and morality. These are the consequences of liberalism and capitalism unleashed and unchecked by the constraining hand of tradition, or a powerful church, or a moralistic and domineering government. Even the Chinese have learned that while it is possible to have capitalism without political liberalization, it is much harder.

Today, radical Islamists are the last holdout against these powerful forces of modernity. For Sayyid Qutb, one of the intellectual fathers of Al Qaeda, true Islam could be salvaged only by warring against the modern world on all fronts. He wanted to "take apart the entire political and philosophical structure of modernity and return Islam to its unpolluted origins." A very different kind of Muslim leader, Ayatollah Khomeini, clearly identified modernity with the Enlightenment and rejected both. "Yes, we are reactionaries, " he told his opponents, "and you are enlightened intellectuals: You intellectuals do not want us to go back 1,400 years."

These most radical Islamists, along with Osama bin Laden, also reject that great product of the Enlightenment and modernity: democracy. Abu Musab al-Zarqawi denounced elections in Iraq on the grounds that "the legislator who must be obeyed in a democracy is man, and not God." Democratic elections were "the very essence of heresy and polytheism and error," for they made "the weak, ignorant man God's partner in His most central divine prerogative--namely, ruling and legislating." As Bernard Lewis has written, the aim of Islamic revolution in Iran and elsewhere has been to "sweep away all the alien and infidel accretions that had been imposed on the Muslim lands and peoples in the era of alien dominance and influence and to restore the true and divinely given Islamic order." One of those "infidel accretions" is democracy. The fundamentalists want to take the Islamic world back to where it was before the Christian West, liberalism, and modernity polluted what they regard as pure Islam.

Their goal is impossible to achieve. The Islamists could not take their societies back 1,400 years even if the rest of the world would let them. And it will not let them. Neither the United States nor any of the other great powers will turn over control of the Middle East to these fundamentalist forces. Partly this is because the region is of such vital strategic importance to the rest of the world. But it is more than that. The vast majority of the people in the Middle East have no desire to go back 1,400 years. They oppose neither modernity nor democracy. Nor is it conceivable in this modern world that a whole country could wall itself off from modernity, even if the majority wanted to do so. Could the great Islamic theocracy that Al Qaeda and others hope to erect ever completely block out the sights and sounds of the rest of the world, and thereby shield its people from the temptations of modernity? The mullahs have not even succeeded in doing that in Iran. The project is fantastic.

The world is thus faced with the prospect of a protracted struggle in which the goals of the extreme Islamists can never be satisfied because neither the United States, nor Europe, nor Russia, nor China, nor the peoples of the Middle East have the ability or the desire to give them what they want. The modern great powers will never retreat as far as the Islamic extremists require. Unfortunately, they may also not be capable of uniting effectively against the threat. Although in the struggle between modernization and tradition the United States, Russia, China, Europe, and the other great powers are roughly on the same side, the things that divide them from one another--the competing national ambitions, the divisions between democrats and autocrats, the transatlantic disagreement over the use of military power--undermine their will to cooperate.

This is certainly true when it comes to the unavoidable military aspects of a fight against radical Islamic terrorism. Europeans have been and will continue to be less than enthusiastic about what they emphatically do not call "the war on terror." As for Russia and China, it will be tempting for them to enjoy the spectacle of the United States bogged down in a fight with Al Qaeda and other violent Islamist groups in the Middle East and South Asia, just as it is tempting to let American power in that region be checked by a nuclear-armed Iran. The willingness of the autocrats in Moscow and Beijing to protect their fellow autocrats in Pyongyang, Tehran, and Khartoum increases the chances that the connection between terrorists and nuclear weapons will eventually be made.

Indeed, one of the problems with making the struggle against Islamic terrorism the sole focus of American foreign policy is that it produces illusions about alliance and cooperation with other great powers with whom genuine alliance is becoming impossible. The idea of genuine strategic cooperation between the United States and Russia or the United States and China in the war on terror is mostly a fiction. For Russia, the war on terror is about Chechnya. For China, it is about the Uighurs of Xinjiang province. But when it comes to Iran, Syria, and Hezbollah, Russia and China tend to see not terrorists but useful partners in the great power struggle.

The great fallacy of our era has been the belief that a liberal international order rests on the triumph of ideas alone, or on the natural unfolding of human progress. It is an immensely attractive notion, deeply rooted in the Enlightenment worldview of which all of us in the liberal world are the product. Our political scientists posit theories of modernization, with sequential stages of political and economic development that lead upward toward liberalism. Our political philosophers imagine a grand historical dialectic, in which the battle of worldviews over the centuries produces, in the end, the correct liberal democratic answer. Naturally, many are inclined to believe that the Cold War ended the way it did simply because the better worldview triumphed, and that the international order that exists today is but the next stage forward in humanity's march from strife and aggression toward a peaceful and prosperous co-existence.

Such illusions are just true enough to be dangerous. Of course there is strength in the liberal democratic idea, and in the free market. It is logical, too, that a world of liberal democratic states would gradually produce an international order that reflected those liberal and democratic qualities. This has been the enlightenment dream since the eighteenth century, when Kant imagined a "perpetual peace" consisting of liberal republics and built upon the natural desire of all peoples for peace and material comfort. Although some may scoff, it has been a remarkably compelling vision. Its spirit animated the international arbitration movements at the end of the nineteenth century, the worldwide enthusiasm for a League of Nations in the early twentieth century, and the enthusiasm for the United Nations after World War II. It has also been a remarkably durable vision, withstanding the horrors of two world wars, one more disastrous than the other, and then a long Cold War that for a third time dashed expectations of progress toward the ideal.

It is a testament to the vitality of this Enlightenment vision that hopes for a brand new era in human history again took hold with such force after the fall of Soviet communism. But a little more skepticism was in order. After all, had mankind really progressed so far? The most destructive century in all the millennia of human history was only just concluding; it was not buried in some deep, dark ancient past. Our supposedly enlightened modernity had produced the greatest of horrors--the massive aggressions, the "total wars," the famines, the genocides, the nuclear warfare. After the recognition of this terrible reality--the relationship of modernity not only to good but also to evil--what reason was there to believe that humankind was suddenly on the cusp of a brand new order? The focus on the dazzling pageant of progress at the end of the Cold War ignored the wires and the beams--the actual historical scaffolding--that had made such progress possible. It failed to acknowledge that progress toward liberalism was not inevitable, but was contingent on events--battles won or lost, social movements successful or crushed, economic policies implemented or discarded. The spread of democracy was not merely the unfolding of certain ineluctable processes of economic and political development. We do not know whether such an evolutionary process--with predictable stages, with known causes and effects--even exists.

What we do know is that the global shift toward liberal democracy coincided with the historical shift in the balance of power toward those nations and peoples who favored the liberal democratic idea, a shift that began with the triumph of the democratic powers over fascism in World War II and that was followed by a second triumph of the democracies over communism in the Cold War. The liberal international order that emerged after these two victories reflected the new overwhelming global balance in favor of liberal forces. But those victories were not inevitable, and they need not be lasting. Now the re-emergence of the great autocratic powers, along with the reactionary forces of Islamic radicalism, has weakened that order, and threatens to weaken it further in the years and decades to come. The world's democracies need to begin thinking about how they can protect their interests and advance their principles in a world in which these are, once again, powerfully contested.

Robert Kagan is senior associate at the Carnegie Endowment for International Peace and senior transatlantic fellow at the German Marshall Fund. His new book, The Return of History and the End of Dreams, will be published by Knopf later this month.