In recent years, the liberal world order that has held sway over international affairs for the past seven decades has been fragmenting under the pressure of systemic economic stresses, growing tribalism and nationalism, and a general loss of confidence in established international and national institutions. The incoming U.S. administration faces a grave challenge in determining whether it wishes to continue to uphold this liberal order, which has helped to maintain a stable international system in the face of challenges from regional powers and other potential threats, or whether it is willing to accept the consequences that may result if it chooses to abandon America’s key role as a guarantor of the system it helped to found and sustain.

The liberal world order established in the aftermath of World War II may be coming to an end, challenged by forces both without and within. The external challenges come from the ambition of dissatisfied large and medium-size powers to overturn the existing strategic order dominated by the United States and its allies and partners. Their aim is to gain hegemony in their respective regions. China and Russia pose the greatest challenges to the world order because of their relative military, economic, and political power and their evident willingness to use it, which makes them significant players in world politics and, just as important, because the regions where they seek strategic hegemony—Asia and Europe—historically have been critical to global peace and stability. At a lesser but still significant level, Iran seeks regional hegemony in the Middle East and Persian Gulf, which if accomplished would have a strategic, economic, and political impact on the international system. North Korea seeks control of the Korean peninsula, which if accomplished would affect the stability and security of northeast Asia. Finally, at a much lower level of concern, there is the effort by ISIS and other radical Islamist groups to establish a new Islamic caliphate in the Middle East. If accomplished, that, too, would have effects on the global order.

However, it is the two great powers, China and Russia, that pose the greatest challenge to the relatively peaceful and prosperous international order created and sustained by the United States. If they were to accomplish their aims of establishing hegemony in their desired spheres of influence, the world would return to the condition it was in at the end of the 19th century, with competing great powers clashing over inevitably intersecting and overlapping spheres of interest. These were the unsettled, disordered conditions that produced the fertile ground for the two destructive world wars of the first half of the 20th century. The collapse of the British-dominated world order on the oceans, the disruption of the uneasy balance of power on the European continent due to the rise of a powerful unified Germany, combined with the rise of Japanese power in East Asia all contributed to a highly competitive international environment in which dissatisfied great powers took the opportunity to pursue their ambitions in the absence of any power or group of powers to unite in checking them. The result was an unprecedented global calamity. It has been the great accomplishment of the U.S.-led world order in the 70 years since the end of the Second World War that this kind of competition has been held in check and great power conflicts have been avoided.

The role of the United States, however, has been critical. Until recently, the dissatisfied great and medium-size powers have faced considerable and indeed almost insuperable obstacles to achieving their objectives. The chief obstacle has been the power and coherence of the order itself and of its principal promoter and defender. The American-led system of political and military alliances, especially in the two critical regions of Europe and East Asia, has presented China and Russia with what Dean Acheson once referred to as “situations of strength” in their regions that have required them to pursue their ambitions cautiously and in most respects to defer serious efforts to disrupt the international system. The system has served as a check on their ambitions in both positive and negative ways. They have been participants in and for the most part beneficiaries of the open international economic system the United States created and helped sustain and, so long as that system was functioning, have had more to gain by playing in it than by challenging and overturning it. The same cannot be said of the political and strategic aspects of the order, both of which have worked to their detriment. The growth and vibrancy of democratic government in the two decades following the collapse of Soviet communism have posed a continual threat to the ability of rulers in Beijing and Moscow to maintain control, and since the end of the Cold War they have regarded every advance of democratic institutions, including especially the geographical advance close to their borders, as an existential threat—and with reason. The continual threat to the basis of their rule posed by the U.S.-supported order has made them hostile both to the order and to the United States. However, it has also been a source of weakness and vulnerability. Chinese rulers in particular have had to worry about what an unsuccessful confrontation with the United States might do to their sources of legitimacy at home. And although Vladimir Putin has to some extent used a calculated foreign adventurism to maintain his hold on domestic power, he has taken a more cautious approach when met with determined U.S. and European opposition, as in the case of Ukraine, and pushed forward, as in Syria, only when invited to do so by U.S. and Western passivity. Autocratic rulers in a liberal democratic world have had to be careful.

The greatest check on Chinese and Russian ambitions, however, has come from the combined military power of the United States and its allies in Europe and Asia.

The greatest check on Chinese and Russian ambitions, however, has come from the combined military power of the United States and its allies in Europe and Asia. China, although increasingly powerful itself, has had to contemplate facing the combined military strength of the world’s superpower and some very formidable regional powers linked by alliance or common strategic interest, including Japan, India, and South Korea, as well as smaller but still potent nations like Vietnam and Australia. Russia has had to face the United States and its NATO allies. When united, these military powers present a daunting challenge to a revisionist power that can call on no allies of its own for assistance. Even were the Chinese to score an early victory in a conflict, they would have to contend over time with the combined industrial productive capacities of some of the world’s richest and most technologically advanced nations. A weaker Russia would face an even greater challenge.

Faced with these obstacles, the two great powers, as well as the lesser dissatisfied powers, have had to hope for or if possible engineer a weakening of the U.S.-supported world order from within. This could come about either by separating the United States from its allies, raising doubts about the U.S. commitment to defend its allies militarily in the event of a conflict, or by various means wooing American allies out from within the liberal world order’s strategic structure. For most of the past decade, the reaction of American allies to greater aggressiveness on the part of China and Russia in their respective regions, and to Iran in the Middle East, has been to seek more reassurance from the United States. Russian actions in Georgia, Ukraine, and Syria; Chinese actions in the East and South China seas; Iranian actions in Syria, Iraq, and along the littoral of the Persian Gulf—all have led to calls by American allies and partners for a greater commitment. In this respect, the system has worked as it was supposed to. What the political scientist William Wohlforth once described as the inherent stability of the unipolar order reflected this dynamic—as dissatisfied regional powers sought to challenge the status quo, their alarmed neighbors turned to the distant American superpower to contain their ambitions.

The system has depended, however, on will, capacity, and coherence at the heart of the liberal world order. The United States had to be willing and able to play its part as the principal guarantor of the order, especially in the military and strategic realm. The order’s ideological and economic core—the democracies of Europe and East Asia and the Pacific—had to remain relatively healthy and relatively confident. In such circumstances, the combined political, economic, and military power of the liberal world would be too great to be seriously challenged by the great powers, much less by the smaller dissatisfied powers.

In recent years, however, the liberal order has begun to weaken and fracture at the core. As a result of many related factors—difficult economic conditions, the recrudescence of nationalism and tribalism, weak and uncertain political leadership and unresponsive mainstream political parties, a new era of communications that seems to strengthen rather than weaken tribalism—there has emerged a crisis of confidence in what might be called the liberal enlightenment project. That project tended to elevate universal principles of individual rights and common humanity over ethnic, racial, religious, national, or tribal differences. It looked to a growing economic interdependence to create common interests across boundaries and the establishment of international institutions to smooth differences and facilitate cooperation among nations. Instead, the past decade has seen the rise of tribalism and nationalism; an increasing focus on the “other” in all societies; and a loss of confidence in government, in the capitalist system, and in democracy. We have been witnessing something like the opposite of the “end of history” but have returned to history with a vengeance, rediscovering all the darker aspects of the human soul. That includes, for many, the perennial human yearning for a strong leader to provide firm guidance in a time of seeming breakdown and incoherence.

This crisis of the enlightenment project may have been inevitable. It may indeed have been cyclical, due to inherent flaws in both capitalism and democracy, which periodically have been exposed and have raised doubts about both—as happened, for instance, throughout the West in the 1930s. Now, as then, moreover, this crisis of confidence in liberalism coincides with a breakdown of the strategic order. In this case, however, the key variable has not been the United States as the outside power and its willingness, or not, to step in and save or remake an order lost by other powers. Rather it is the United States’ own willingness to continue upholding the order that it created and which depends entirely on American power.

That willingness has been in doubt for some time. Increasingly in the quarter-century after the end of the Cold War, Americans have been wondering why they bear such an unusual and outsized responsibility for preserving global order when their own interests are not always apparently served and when, indeed, the United States seems to be making sacrifices while others benefit. The reasons why the United States took on this abnormal role after the calamitous two world wars of the 20th century have been largely forgotten. As a consequence, the American public’s patience with the difficulties and costs inherent in playing such a role has worn thin. Thus, whereas previous unsuccessful wars, in Korea in 1950 and Vietnam in the 1960s and 1970s, and previous economic downturns, such as in the mid- to late 1970s, did not have the effect of turning Americans against global involvement, the unsuccessful wars in Iraq and Afghanistan and the financial crisis of 2007–09 have had that effect. President Obama pursued an ambivalent approach to global involvement, but the main thrust of his approach was retrenchment. His actions and statements were a critique of previous American strategy and reinforced a national mood favoring a much less active role in the world and much narrower definition of American interests.

With the election of Donald Trump, a majority of Americans have signaled their unwillingness to continue upholding the world order. Trump was not the only candidate in 2016 to run on a platform suggesting a much narrower definition of American interests and a lessening of the burdens of American global leadership. “America First” is not just an empty phrase but a fairly coherent philosophy with a long lineage and many adherents in the American academy. It calls for viewing American interests through a narrow lens. It suggests no longer supporting an international alliance structure, no longer seeking to deny great powers their spheres of influence and regional hegemony, no longer attempting to uphold liberal norms in the international system, and no longer sacrificing short-term interests—in trade for instance—in the longer-term interest of preserving an open economic order.

Coming as it does at a time of growing great power competition, this new approach in American foreign policy is likely to hasten a return to the instability and clashes of previous eras. These external challenges to the liberal world order and the continuing weakness and fracturing of the liberal world from within are likely to feed on each other. The weakness of the liberal core and the abdication by the United States of its global responsibilities will encourage more aggressive revisionism by the dissatisfied powers, which may in turn exacerbate the sense of weakness and helplessness and the loss of confidence of the liberal world, which will in turn increase the sense on the part of the great power autocracies that this is their opportunity to reorder the world to conform to their interests.

History suggests that this is a downward spiral from which it will be difficult to recover absent a major conflict. It was in the 1920s, not the 1930s, that the most important and ultimately fatal decisions were made by the liberal powers. Above all, it was the American decision to remove itself from a position of global responsibility, to reject strategic involvement to preserve the peace in Europe, and neglect its naval strength in the Pacific to check the rise of Japan. The “return to normalcy” of the 1920 U.S. election seemed safe and innocent at the time, but the essentially selfish policies pursued by the world’s strongest power in the following decade helped set the stage for the calamities of the 1930s. By the time the crises began to erupt in that decade, it was already too late to avoid paying the high price of global conflict.

One thing for the new administration to keep in mind: History tells us that revisionist great powers are not easy to satisfy short of complete capitulation. Their sphere of influence is never quite large enough to satisfy their pride or their expanding need for security. The “satiated” power that Bismarck spoke of is rare—even his Germany, in the end, could not be satiated. And of course, rising great powers always express some historical grievance. Every people, except perhaps for the fortunate Americans, have reason for resentment at ancient injustices, nurse grudges against old adversaries, seek to return to a glorious past that was stolen from them by military or political defeat. The world’s supply of grievances is inexhaustible.

These grievances, however, are rarely solved by minor border changes. Japan, the aggrieved “have-not” nation of the 1930s, did not satisfy itself by swallowing Manchuria in 1931. Germany, the aggrieved victim of Versailles, did not satisfy itself by bringing the Germans of the Sudetenland back into the fold. And, of course, Russia’s historical sphere of influence does not end in Ukraine. It begins in Ukraine. It extends to the Baltics, to the Balkans, and to heart of Central Europe. The tragic irony is that, in the process of carving out these spheres of influence, the ambitious rising powers invariably create the very threats they use to justify their actions. The cycle only ends if and when the great powers that make up the existing power structure, in today’s case, the United States, decide they have had enough. We know those moments as major power wars.

The new administration seems to be fixated almost entirely on the threat of radical Islam and may not believe its main problem is going to be great power confrontation. In fact, it is going to have to confront both sets of challenges. The first, addressing the threat of terrorism, is comparatively manageable. It is the second, managing great power competition and confrontation, that has historically proved the most difficult and also the most costly when handled badly.

The best way to avoid great power clashes is to make the U.S. position clear from the outset.

The best way to avoid great power clashes is to make the U.S. position clear from the outset. That position should be that the United States welcomes competition of a certain kind. Great powers compete across multiple planes—economic, ideological, and political, as well as military. Competition in most spheres is necessary and even healthy. Within the liberal order, China can compete economically and successfully with the United States; Russia can thrive in the international economic order upheld by the liberal powers, even if it is not itself liberal.

But security competition is different. The security situation undergirds everything else. It remains true today as it has since the Second World War that only the United States has the capacity and the unique geographical advantages to provide global security. There is no stable balance of power in Europe or Asia without the United States. And while we can talk about soft power and smart power, they have been and always will be of limited value when confronting raw military power. Despite all of the loose talk of American decline, it is in the military realm where U.S. advantages remain clearest. Even in other great powers’ backyards, the United States retains the capacity, along with its powerful allies, to deter challenges to the security order. But without a U.S. willingness to use military power to establish balance in far-flung regions of the world, the system will buckle under the unrestrained military competition of regional powers.

If history is any guide, the next four years are the critical inflection point. The rest of the world will take its cue from the early actions of the new administration. If the next president governs as he ran, which is to say if he pursues a course designed to secure only America’s narrow interests; focuses chiefly on international terrorism—the least of the challenges to the present world order; accommodates the ambitions of the great powers; ceases to regard international economic policy in terms of global order but only in terms of America’s bottom line narrowly construed; and generally ceases to place a high priority on reassuring allies and partners in the world’s principal strategic theaters—then the collapse of the world order, with all that entails, may not be far off.

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