The war in Ukraine shattered a core assumption about great-power dominance: that size and military strength are enough to impose one\u2019s will. Ukraine showed otherwise. With the right strategy, geography, and resolve, a weaker state can survive and blunt – and in key respects even defeat – a much stronger adversary.<\/p>\n
The United States now faces an uncomfortable parallel. The war with Iran<\/a> is exposing similar limits to American power.<\/p>\n For decades, U.S. grand strategy has rested on primacy \u2014 the belief that America\u2019s unmatched military capabilities enabled it to uphold global stability and shape outcomes across regions.<\/p>\n After the failures in Iraq and Afghanistan, many Americans have reached a stark conclusion: the cost of primacy is no longer sustainable \u2014 and no longer serves U.S. interests. A strategy that depends on military dominance everywhere, all the time, inevitably means being at war somewhere, all the time. America\u2019s endless wars are not an accident; they are the product of this approach. And if there is one rare point of agreement in a deeply divided country, it is this: Americans are tired of war.<\/p>\n Yet despite a war-weary public, mounting fiscal strain, and politicians who promise to end endless wars, inertia\u2014and powerful economic interests tied to war \u2014 have kept primacy intact.<\/p>\n The question now is whether the debacle in Iran will finally break that pattern. Early signs suggest its repercussions may exceed even those of George W. Bush\u2019s war of choice in Iraq.<\/p>\n Consider this: the United States won the Iraq war in under three weeks. Its military dominance was never in doubt. But it lost the peace \u2014 failing to stabilize the country once the insurgency took hold.<\/p>\n In Iran, however, the United States didn\u2019t even win the military phase \u2014 despite facing a far weaker conventional force. Iran leveraged geography and asymmetric tactics to blunt American power and inflict a strategic setback. Even more striking, early claims that U.S. airstrikes had significantly degraded Iran\u2019s drone and missile capabilities now appear overstated. The lesson is clear: control of the skies does not guarantee control of outcomes. Without the will to deploy ground forces\u2014and without the ability to translate airpower into decisive results \u2014 American primacy begins to look increasingly hollow.<\/p>\n Second, as Stephen Walt has noted<\/a>, even though the Iraq war ultimately failed, it did achieve its immediate objective: the overthrow of Saddam Hussein. In Iran, the opposite appears to be happening. Rather than weakening the regime, the war has likely strengthened it \u2014 consolidating internal cohesion and reinforcing hardline control.<\/p>\n Walt further notes that while the Iraq war destabilized the region, its global repercussions were relatively contained. It did not trigger an oil crisis, widespread food shortages, or major supply chain disruptions. The Iran war, by contrast, has already sent energy markets into turmoil \u2014 driving oil and gas prices to record highs and triggering energy emergencies in multiple countries. It may also have fundamentally reshaped the geopolitical landscape of the Persian Gulf for years to come.<\/p>\n As Stephen Wertheim has argued, primacy was always a choice<\/a> \u2014 not a necessity. The Iran war suggests it may no longer even be a viable one. A strategy built on escalation dominance falters when escalation itself becomes too risky to use. One that relies on decisive victories breaks down when adversaries can consistently impose stalemate.<\/p>\n What emerges instead is a different kind of international order \u2014 one not defined by dominance, but by mutual denial. In this world, great powers cannot easily impose their will, and smaller states can resist them at tolerable cost. The result is not chaos, but constraint.<\/p>\n The most likely outcome of the current US-Iran stand-off is neither a deal nor a return to war, but a prolonged, uneasy equilibrium. That, too, is a sign of the times. The United States may walk away from negotiations, but it is unlikely to reenter a full-scale war. Not because it lacks the capability \u2014 but because it lacks the strategic freedom to use it.<\/p>\n For states who have opted to depend on American protection, this should be a wake-up call.<\/p>\n This does not mean alliances will collapse. But it does mean they will change. Allies will hedge more, diversify their security relationships, and place greater emphasis on regional balances of power rather than reliance on a single guarantor.<\/p>\n In that sense, the Iran war is not a rupture so much as an accelerant of a trend already underway. Iraq and Afghanistan exposed the limits of occupation and regime change. Ukraine exposed the vulnerability of large conventional forces. Iran now exposes the limits of coercion itself. As my colleague at the Quincy Institute Monica Toft argues<\/a>, other smaller powers don\u2019t need a vital waterway as the Strait of Hormuz<\/a> to effectively constrain a superpower. The shaping of terrain and geography \u2014 as the Ukrainians have done \u2014 is sufficient. In short: Iran\u2019s strategy is replicable elsewhere.<\/p>\n Taken together, these conflicts point to a more multipolar world \u2014 not because new great powers have fully risen, but because existing ones can no longer dominate as they once did.<\/p>\n The danger for Washington is not irrelevance. It is that we continue to pursue a strategy designed for a world that no longer exists. The same is true for countries that have chosen to rely on American primacy.<\/p>\n Primacy promised control. The Iran war reveals constraint. And in the gap between promise and reality lies the end of an era. The winners will be those who adjust.<\/p>\n