Shortly after taking office, US Secretary of State Marco Rubio described unipolarity as “an anomaly”—a product of the Soviet collapse rather than the natural condition of the international system, which would eventually return to a more multipolar form. This admission matters. For more than three decades, American grand strategy rested on the belief that the United States had entered a durable era of uncontested primacy. The current administration’s most senior diplomat now acknowledges that this era is over.
But naming a new era is not the same as adapting to it. Three decades of unipolar habit do not disappear after a speech. Across the Middle East, the Atlantic, and the Indo-Pacific, Washington still behaves as though the structural limits of a multipolar world can be managed away. The result is a widening gap between diagnosis and practice —between how Washington describes the international system and how it continues to act within it. America’s rivals are already using that gap to their advantage.
The end of the unipolar era is no longer a fringe claim. Foreign policy expert Christopher Layne argued as early as 2006, in International Security, that American primacy was unsustainable and that multipolarity was already re-emerging. Stephen Brooks and William Wohlforth, writing in the same journal in 2015, offered a forceful defense of unipolarity’s durability, but even they acknowledged that China’s rise would impose trade-offs on US grand strategy. In his 2014 book Restraint, political scientist Barry R. Posen urged the United States to scale back peripheral commitments and reserve its resources for core national-security objectives.
Emma Ashford’s recent First Among Equals makes the case for “realist internationalism” in what she calls “unbalanced multipolarity,” while her Foreign Affairs essay on “Making Multipolarity Work” urges Washington to preserve its advantages without overextending itself. C. Raja Mohan, by contrast, has argued in the same journal that talk of multipolarity is premature: The United States, in his view, remains the only power capable of shaping the international system, even as it sheds some of the responsibilities that once accompanied primacy.
This essay engages both sides of that debate but identifies a problem that neither side fully captures: the persistence of unipolar operational habits after the rhetorical acknowledgment of systemic change. Whether one agrees with Mohan that unipolarity still endures, or with Ashford that multipolarity has arrived, American statecraft is increasingly failing on its own terms. The gap between declaratory posture and operational conduct has become a strategic vulnerability. That gap—between acknowledgment and adaptation—is what we call the unipolar delusion.
The Structural Shift Washington Has Not Absorbed
Structural realists have long argued that the distribution of power among states is the primary determinant of international behavior. When that distribution changes, strategy must change with it. As John J. Mearsheimer showed in The Tragedy of Great Power Politics, multipolar and bipolar systems produce a different strategic environment—one marked by sharper rivalry and narrower margins for error. A unipolar power can absorb a certain amount of strategic indiscipline because no rival can exploit its distractions at systemic scale. Once that condition ends, the costs of error rise quickly.
Brooks and Wohlforth’s counterargument was not wrong at the time: American unipolarity was so pronounced, and the gap between the United States and potential challengers so wide, that Washington could absorb a degree of strategic indiscipline without facing immediate systemic consequences. But it depended on a material distribution that has since eroded. Even Mohan’s recent defense of continued American preponderance concedes that the United States now exercises “unilateral power shorn of responsibilities,” a formulation that inadvertently confirms the recklessness this essay diagnoses. The cushion that once made serial overextension survivable has grown thin.
The United States is no longer operating in a unipolar system. China has emerged as a peer competitor; Russia retains the capacity to revise the European order through force; and regional powers now exercise degrees of autonomy that would have been hard to imagine in the 1990s. The 2025 National Security Strategy formally recognizes aspects of this reality, framing the era in terms of great-power jockeying and balance-of-power politics rather than uncontested US primacy.
Yet many of the assumptions embedded in American statecraft still belong to an earlier moment: that the United States can act in several theaters at once without serious systemic trade-offs; that military superiority will translate into favorable political outcomes; and that allies will remain available regardless of how Washington treats them.
Iran: Strategic Distraction
The US-Israeli war on Iran shows the danger clearly. Operation Epic Fury, launched on February 28, 2026, has been tactically effective by narrow military measures. American and Israeli forces have degraded Iranian air defenses, struck nuclear facilities, and neutralized significant parts of Tehran’s ballistic missile arsenal.
But strategy cannot be judged by target lists alone. Iran closed the Strait of Hormuz with antiship missiles, drones, and mines—a contingency that even the most sophisticated air campaigns could not prevent. Oil markets convulsed. Gulf partners, hit by Iranian retaliation for their cooperation with US operations, began hedging their relationships with Washington. A ceasefire brokered in April 2026 paused the fighting without resolving the underlying political contest.
The June 15 Memorandum of Understanding between Washington and Tehran reopened the Strait of Hormuz and initiated a new round of negotiations over Iran’s nuclear program, but it did not settle the underlying regional rivalry. Indeed, some observers have argued that the agreement largely reflects the limits of coercive diplomacy. Michael Hirsh, for example, described it as a “surrender document” that leaves both the United States and Israel strategically weaker than before the conflict. Whether or not one accepts that characterization, the agreement underscores a broader point: after months of military operations and significant resource expenditures, Washington ultimately arrived at an outcome that fell short of a decisive political resolution. The durable strategic gains that would justify the intervention remain elusive.
Intervention has depleted American resources, damaged Washington’s reputation, and raised global fuel prices. If anything, the campaign has confirmed a basic realist insight: Military superiority does not automatically produce political control. As Ryan Evans has written, the administration “confused the instrument for the purpose”—a textbook example of the gap between operational excellence and strategic coherence. Iran is not an exception. It is part of a recurring pattern in which a superpower mistakes the ability to destroy for the ability to shape durable political outcomes.
The systemic costs accumulated quickly. During the period of disruption in the Strait of Hormuz, higher energy prices generated substantial additional revenues for Russia, providing Moscow with an economic windfall at a time when Washington sought to constrain its war-making capacity in Europe. Although the June 15 agreement and the—still contested—reopening of the Strait will ease pressures on global energy markets, the episode nevertheless illustrates how instability in a secondary theater can produce unintended benefits for major geopolitical competitors.
China, meanwhile, has used the crisis to present itself as a voice of regional stability. Foreign Minister Wang Yi conducted 26 diplomatic phone calls in the weeks surrounding the ceasefire, while special envoy Zhai Jun held nearly two dozen meetings with regional actors. Beijing cast itself as a responsible power committed to keeping the Strait of Hormuz open, contrasting its posture with a United States embroiled in a costly campaign with uncertain political aims. In a post-unipolar order, every American overcommitment gives rivals a chance to expand their legitimacy and reach.
Senator Lindsey Graham has described US action in Iran and Venezuela as “China’s nightmare.” The evidence points in the other direction. A United States bogged down in Middle Eastern campaigns, alienating Gulf partners, and consuming defense resources in theaters peripheral to the Sino-American competition is not a nightmare for Beijing.
It is a strategic gift—and a more useful one than China could have produced on its own. The pattern is already visible: the redeployment of US missile-defense assets from South Korea to the Gulf, the depletion of cruise-missile inventories earmarked for Pacific contingencies, and the diplomatic gains Beijing has made by presenting itself as a stabilizing actor while Washington wages an unpopular war of choice. The aftershocks of the Iran campaign are already being felt in exactly the theaters where American attention is most needed.
Alliances Still Matter
Alliances are the second place where unipolar habits linger. In a unipolar system, alliances may look like useful accessories to power rather than essential foundations of it. The dominant state can absorb allied defection or burden-sharing disputes because its margin of superiority is large enough to make such losses manageable. In a multipolar order, alliances become structurally decisive. They multiply capability, complicate adversary calculations, distribute costs, and extend strategic reach. Neglecting them is not a display of autonomy. It is a subtraction from relative power.
In realist terms, alliances are not charity; they are force multipliers that allow the leading state to project power at lower cost and with greater legitimacy than it could achieve alone. Mearsheimer and Stephen M. Walt’s offshore-balancing framework, outlined in their 2016 Foreign Affairs essay, rested on precisely this logic: The United States should rely on regional allies to carry the primary burden of local balancing, intervening directly only when no local coalition can contain a potential hegemon. Ashford’s realist internationalism updates that prescription for an era of unbalanced multipolarity, calling on Washington to foster allied capability rather than demand allied compliance. The current administration is inverting both frameworks. It demands more from allies while giving them less reason to comply.
US President Donald Trump has put the logic of American extended deterrence with unusual bluntness: Allies who “don’t pay,” he has stated, will not be defended. Burden-sharing reform is a legitimate concern. But the manner and timing of the pressure—from Vice President JD Vance’s February 2025 Munich address to threats against Greenland—have encouraged measurable allied hedging toward China and reinforced the perception that the United States has become not only unreliable but also a source of instability.
That is the larger danger. Washington risks squandering what remains its single most important structural advantage over China: an alliance network that Beijing cannot replicate. China has no equivalent set of security partnerships in Europe, the Indo-Pacific, and the Middle East. The United States does. That network is not merely a legacy of the liberal international order. It is a power multiplier in a competitive state system. Treating it as a burden rather than a strategic asset does not project strength. It weakens the very foundation of American power.
The Price of Unipolar Habits
At the root of both pathologies—overextension in the Middle East and corrosion of alliances—lies a conceptual confusion realists have long identified: the conflation of military predominance with political control. American leaders across administrations have often acted as though superior force generation reliably produces favorable outcomes. It does not, and it did not even during the unipolar era. The lesson of Iraq, Afghanistan, Libya, and now Iran is consistent. Overwhelming military capability can destroy and degrade adversaries, but it cannot by itself produce durable political settlements.
Iran does not need to defeat the United States militarily. It needs only to prevent Washington from turning military superiority into lasting political gains—a task it has shown it can perform. Posen’s restraint school anticipated precisely this problem: the mismatch between military dominance and political outcomes in peripheral theaters. But the current problem is more specific than the general case for restraint. The United States is not simply overextended. It is overextended while admitting that overextension is unsustainable. The doctrinal language has shifted; the operational adjustment has not. That is the distinctive pathology of the present moment, and it is more dangerous than straightforward overreach because it creates the illusion that strategic recalibration is already underway.
Under unipolarity, repeated strategic miscalculations were survivable because no peer competitor could exploit them at scale. In a multipolar or bipolar system, they are not. Each open-ended commitment in the Middle East consumes attention and military capacity that cannot be devoted to the Indo-Pacific. Each deterioration of the transatlantic alliance narrows the coalition available to balance China. Each policy that drives energy prices upward enriches Moscow and tightens the fiscal pressure on European partners already struggling to rearm. Opportunity costs that unipolarity once made tolerable now compound with every strategic mistake.
Senior figures within the administration have framed the necessary recalibration as putting things on a more sustainable basis. Sustainability is exactly the right standard. The question is whether American statecraft is moving toward sustainability in practice, or whether the language of discipline is being layered onto the old habits of overextension.
What Strategic Adjustment Requires
A genuinely realist adaptation to the post-unipolar order would begin with principles that classical balance-of-power theory has always supplied. The first is prioritization. Not all theaters carry equal strategic weight. The Indo-Pacific—where the central competition between the United States and China will be decided—is categorically more important than the Middle East, where American power has repeatedly been consumed without commensurate strategic return.
A disciplined great power does not treat every challenge as equally urgent. It identifies the primary theater and calibrates its commitments accordingly. Hal Brands and Michael Beckley have made a version of this argument in their 2022 book Danger Zone: The Coming Conflict with China, warning that the window for managing the Sino-American competition is narrowing and that peripheral engagements can make that window harder to navigate. The Iran campaign is a case study in exactly the kind of distraction they cautioned against.
The second principle is selectivity in the use of force. Operations that do not advance the primary strategic objective—managing the Sino-American competition—impose costs on military readiness, alliance cohesion, and credibility. That calculus mattered less in a unipolar system. It is central in the present one.
The third is the cultivation of alliances as instruments of power. America’s alliance network is a product of realist calculation, not a gift from liberal internationalism. Preserving it requires treating allies as partners, not subordinates.
The Unipolar Delusion
Great powers rarely decline simply because rivals grow stronger. They decline when they fail to adjust their ambitions and habits to a changed structural environment. The United States is not doomed to decline. Its military capabilities remain formidable, its alliance network is unmatched, and its technological base is deep. But the conditions under which those assets must be deployed have changed fundamentally.
The unipolar delusion is not the belief that America is still omnipotent. Most American officials would reject that claim. The delusion is subtler and more dangerous: the habit of acting as though the limits on American power remain less binding than they have become —as though each commitment can be managed in isolation, each alliance will endure regardless of how it is treated, and each rival will remain unable to exploit American distraction. Those habits were forged in a world that no longer exists. Abandoning them is not a concession to American weakness. It is the precondition for sustaining American strength.
The scholarly debate over American grand strategy has long been framed as a contest between primacy and restraint. The unipolar delusion points to a third, underexamined condition: a state that has adopted the language of strategic discipline while continuing to operate on the assumptions of unchallenged dominance. Mohan may be right that no rival can yet stop the United States. The more urgent question is whether the United States can stop itself from squandering the advantages that make that observation true. Recognizing this condition—and correcting it—is now one of the central tasks of American strategy.
Giorgi Gvalia is a professor of international relations at Ilia State University in Tbilisi.
Bidzina Lebanidze is a political scientist at Friedrich Schiller University Jena, where he leads the BMBF-funded “Jena-Cauc” research project on the South Caucasus.
