Great power stirs a great temptation: to be alone, unencumbered by others, free to act when the spirit moves, and, by virtue of one’s own strength, secure from the rapaciousness of enemies. The drive toward self-reliance, however, can result in loneliness — and loneliness, in our individual life as well as in the life of our nation, is dangerous. It exposes us to risks that we have to face alone, taxing our resources and attention, and does nothing to decrease the threats that are bound to arise nearby or far away. On the contrary, perceiving an opportunity in the solitary existence of the great power, rivals will only increase their predatory reach. The temptation to be alone, without allies, is costly, and even the most powerful should avoid succumbing to it.
In foreign policy, this temptation translates into the belief that allies are a burden rather than a benefit. They cost money because they require protection or other goods to keep them on our side. They limit our freedom of action by tying us to their security. They can entangle us in local controversies of little immediate interest to us. The list goes on, and reasons to spurn alliances can be generated ad infinitum.
In the United States, the temptation to be alone — and the resulting skepticism toward alliances — is a recurring theme that appears on both sides of the political spectrum. For many on the political left, allies are at best unnecessary because the principal security challenges are global in nature, requiring a “global community” to act in unison. Our focus on a few select states, that is, on allies, can detract from our ability to build global partnerships. Hence, Japan and China, Poland and Russia, Israel and Iran are all equally needed partners to combat climate change or global poverty. These were the underlying premises of the strategy of the Obama presidency that, translated into practice, weakened alliances and gave up-front concessions to rivals such as Russia (the “reset”) and Iran (the “Iran deal”) in the hope of future partnerships and participation in a “global community.”
For many on the political right, on the other hand, allies are ungrateful free riders or perilous sources of entanglement in distant and inscrutable games of power. According to this view, strategic rivals exist but U.S. protection of allies (and, in some cases, American military presence in their territory) only exacerbates the hostility of enemies while creating perverse incentives for the allies by providing their defense at little or no cost to them. It would be preferable, the argument goes, to leave allies on their own, forcing them to face the stark geopolitical reality without U.S. security guarantees. Left to their own wits, these states would either defend themselves or seek some form of accommodation with a neighboring rival. Neither decision would affect in a considerably negative way the security of the U.S., its power and geography buffering any harmful consequence.
Of course, these sets of arguments contain kernels of truth. Allies are indeed not doing enough to maintain regional balances of power and should spend considerably more on their own defense. And there are problems, from nuclear proliferation to Islamist terrorism, that would be addressed more effectively through cooperation among rival great powers. These are decent wishes. But it would be a tragedy to allow them to shape U.S. grand strategy and lead Washington to shed or even weaken its alliances. The U.S. should continue to nurture a preference for allies.
Alliances are one of the enduring assets of the United States. The U.S. may be an empire, but it is an empire of alliances, not of colonies and dependencies. Allies set the U.S. apart from its rivals, competitors, and enemies — most of whom have few if any allies. Indeed, these powers, from Russia to China to Iran, seek protectorates and claim glory from conquest (e.g., Russia in Ukraine) or from financial enslavement (e.g., China along its “One Belt, One Road” project) rather than from the free association of polities. These authoritarian states have fully succumbed to the temptation of solitary powers mentioned above. This doesn’t make them any less dangerous; on the contrary, incapable of weaving a belt of friendly allies around them and in support of their interests, they see only hostile targets of conquest. Solitary powers are inherently more aggressive and violent.
But the value of allies for the United States is much more than as a mark distinguishing it morally from its rivals. Allies are indispensable for the United States and are only becoming more so. Four interrelated reasons for this are worth considering: geography, the costs of projecting power, the nature of modern technology, and, perhaps most important, the fragility of political order.
The geographic nature of American power supplies an enduring reason that the United States needs allies. While the United States is a state of continental proportions, it is also a maritime power. Its economic and geopolitical heft is based on freedom of navigation on the oceans. But, as has been true for all other maritime powers in history, the seas are only the links to other regions from and with which the polity grows and maintains its well-being. Freedom of navigation, which depends on the ability of the U.S. or a friendly power to command the seas, is a means, not an end in itself. It supplies the United States with access to the world, expanding market possibilities and protecting it from potential foes with nefarious aspirations. This is where allies come in: They shape the political and economic life on the other side of the oceans, especially in Eurasia, instilling there the indispensable regional stability, domestic order, and economic growth.
Through these allies, a maritime power such as the United States can shape political dynamics in distant regions, a feat that is impossible by merely controlling the seas and too costly to achieve through direct control. For a maritime power, alliances are an efficient and cheap way to be more than a state with a large navy.
Another way to put this is that controlling the seas is necessary but insufficient to the United States. Oceans (and, since the mid 20th century, air and space) are highways rather than protective moats. Without allies on the other shore, mainly in Europe and Asia, the welfare and security of the U.S. would demand an impossibly large expenditure of resources in order to build a navy, air force, and some sort of “space force” to protect us from the likely rise of an enemy. Even then, it is doubtful that the U.S. would be safe from hostile actors whose strategy is to avoid American strengths and use American technology and politics to inflict damage. The U.S. cannot outspend its rivals, and attempting to do so will lead to fiscal overextension.
An overly confident trust in the geographic separation of the U.S. from the rest of the world has often translated into policy arguments in favor of withdrawing into a “hemispheric defense” — a posture that does not require allies or friendly states on the other shores of the Pacific and Atlantic oceans. War and the collapse of an existing equilibrium of power in 1914 and 1939 woke Americans up to the bankruptcy of this tempting vision of not needing allies and not having to support them. Much intellectual effort went into debunking this temptation in the 1940s, with thinkers such as Nicholas Spykman and Walter Lippmann penning books and essays demonstrating the dangers and costs of being a maritime power without allies in Europe and Asia. But the temptation remained, and the naïve belief that oceans combined with the naval prowess of the United States would suffice to provide peace, security, and well-being festered.
Since then, the importance of alliances has only increased. In large measure this has to do with technological changes that have altered the strategic landscape. For one, allies provide needed entry points into particular regions, especially for maritime and thus geographically distant powers such as the United States. Were the U.S. to lose its allies, a reentry into Europe or Asia would be exceedingly difficult and, most likely, simply unfeasible because of the required costs.
Projecting power into a distant land across the sea has always been an arduous proposition, but the array of defensive technologies developed in recent decades is making it even more difficult than in the past. The so-called “anti-access/area denial” set of capabilities that most of our rivals, and China and Russia in particular, have been adeptly developing is a vivid example of this trend. As a result, a 21st-century version of a D-Day or a slow accumulation of American and allied forces such as the one in Saudi Arabia preceding the 1991 Gulf War against Iraq is likely to be prohibitively expensive and politically impossible for the United States. Continued American support for allies in Europe and Asia (and continued military presence there) is the cheaper and perhaps only way of keeping stability and order.
Another reason allies are more important now than in earlier moments in history is again tied to technology, in particular to its complexity. Alliances acquired and maintained in peacetime can train together and develop technologies and processes that allow them to be more coordinated. The term used in policy discussions is “interoperability,” the ability of allied forces to function in coordination with each other. Obviously this is not a new challenge. Differences in language, for example, created headaches for commanders of multinational coalitions throughout history. Similarly, variations in training and discipline, or in the use of a particular weapon, often weakened the effectiveness of an allied force in the field.
What is new is the level of complexity of technology, making it even more difficult than ever before to coordinate quickly and effectively. Communication systems may vary and impede tactical coordination; targeting systems may be incompatible; armored vehicles may be too heavy for local bridges or railroads; the list continues. To have allies that are useful, therefore, requires time to develop coordination and interoperability — and this is something that will be difficult to achieve during wartime. Cultivating allies now is a necessary investment for the future.
Undoubtedly, allies in Europe and Asia should spend more on their defense. The anemic defense spending of many U.S. allies, in Europe in particular, is a dereliction of basic obligations to their own citizens and to the alliance. The Trump administration correctly identified low defense spending by U.S. allies as a threat to shared security and not merely a domestic political problem for American politicians forced to justify to their electorates U.S. defense commitments to self-disarmed allies. Some allies are increasing their investment in defense, responding to the persistent wake-up calls from Washington and conscious that predatory powers are becoming more assertive, but there is a risk that these allies will fund systems only if they are produced by European countries, resulting in less interoperability with U.S. technologies. Some European politicians, such as French president Emmanuel Macron, claim that Europe should be self-sufficient for its security. The reason for such a call may be a visceral dislike of President Trump or a desire to restore French grandeur, but the result, if this is translated into practice, is that a “Europe only” security policy will prioritize development and acquisition of only European weapons. Some European allies, therefore, may end up increasing their defense budgets but weakening allied effectiveness. Not every dollar or euro more translates equally into a more cohesive and effective alliance.
We can accept all these rationales for alliances but still support an American disengagement from allies. After all, technologies come and go and may be more compatible than expected, the “anti-access/area denial” bubbles erected by our rivals may crumble on their own or be made useless by new capabilities, and maritime powers can perhaps deter rivals simply by virtue of their naval prowess.
But the importance of allies to the U.S. transcends all these reasons. Allies, first and foremost, are a source of order. The survival of U.S. allies as independent entities, in particular those along the vulnerable frontlines of present rivalries, is in itself a linchpin of stability and order — political goods that benefit both the U.S. and its allies. Geopolitical pluralism in Eurasia guarantees that no hostile power develops unchecked by local forces and thus becomes all the more directly dangerous to the United States. International order though geopolitical pluralism — that is broadly the goal of U.S. foreign policy.
Another way to put this is that actors at the local level are most effective at maintaining stability and order. U.S allies located on a frontline that goes from the Baltic through the Black Sea, Eastern Mediterranean, and Persian Gulf, and along the Indo-Pacific rim-land have an innate incentive to do maintain stability and order because they would suffer the most — and the most immediately — from the collapse of the order. The revisionist powers — Russia, China, Iran — make no secret of their desire to alter the status quo and rewrite the existing rules to benefit themselves. They are occupying neighboring states, destabilizing more distant ones, and extending control over the political and economic lives of others. U.S. allies that are in the path of these predatory powers are interested in opposing and checking them in order to keep the status quo. They are not interested in some abstract order based on global rules and are not in search of a vacuous global community of partners. They seek security and order through alliances and, increasingly, through rearmament. They want to preserve the existing geopolitical order because it is in their interest to do so.
One can wonder, can U.S. allies keep their regional orders without U.S. military presence and expenditure? Can the U.S. remain in its own hemisphere and maintain allies that stabilize Eurasia? The answer is simple: No.
All states make constant calculations about the likelihood of their survival and success, and when the chances are deemed low, they tend to adapt by accommodating the nearest and most evident threat. A few states, even if alone, may stay firm in adamant opposition to their enemies because doing otherwise would likely spell a tragic end (for instance, Israel facing Iran). But most would choose accommodation with the revisionist neighbor over destruction or poverty. Credible American security guarantees are necessary to tilt the calculation of these vulnerable states in favor of balancing against Russia, China, or Iran. Alone, they will fold; as confident allies of the United States, they will keep the regional order.
An international political order that allows nations — and their component groups, families, churches, friends, and individuals — to prosper is a geopolitical good that is worth protecting. It is also fragile, like all forms of political order built by men, and demands constant vigilance. The United States cannot protect it alone and would suffer from the geopolitical chaos that might arise and from the strengthening of hostile and predatory powers in Eurasia. The alliances that the United States has carefully curated over the past century contribute to the preservation of order. And they do it at a cost that is considerably lower than were the U.S. to do it alone.
There is nothing in history or in current events to justify the belief that nations and states will converge into peace and harmony. Order and stability has to be imposed and preserved by willful actors, ready to oppose in words and deeds the destabilizing actions of states such as Russia, China, and Iran. International organizations and global norms won’t do it, and there is no automatic balance of power that will arise without the active participation of the United States. Prudent Western — and American — leaders will continue to expect geopolitical rivalries and enmities and, if wise, they will prepare for wars, even those pitting great powers against one another. Above all, they will continue to value the allies that underwrite and preserve the geopolitical order, which, however imperfect, is still better than the alternatives.