Since Donald Trump’s return for a second term as president of the United States, the relentlessness with which his team has dismantled state institutions it considers hostile to its agenda has shaken the foundations of US global power. With so many cultural references to Ancient Rome embedded in the aesthetic of the American Republic, the extent to which Trump has fueled instability at home and abroad has increasingly evoked parallels with the fall of a Roman Empire whose dominance had once seemed equally unassailable.
For Europeans, the uncertainties generated by indications that Trump may seek to destroy the US’ alliance with Europe are beginning to resemble the strategic challenges faced by Emperor Justinian and other East Roman leaders in fifth and sixth-century Constantinople, who struggled to contain the chaos caused by the collapse of their partners in the West Roman Empire.
Fears that relations between the US and Europe might be on the verge of an irreversible breakdown have been heightened by the willingness of MAGA Republican leaders such as Vice President JD Vance or Elon Musk to express open hostility toward America’s traditional allies. Whether it is through efforts to bully Ukraine into concessions toward the Russian invaders, ambitions to seize Greenland, or the imposition of punitive tariffs on European Union goods, the Trump administration’s disputes with European allies have generated a growing list of pretexts to legitimize an American military withdrawal from Europe that would mark as massive a historical rupture as the retreat of Roman legions from Western Europe.
For European policymakers struggling to anticipate risks generated by an escalating crisis of American power, examining strategic lessons from the decline and fall of previous hegemonic empires could prove crucial to securing the survival of the EU and its partners in a post-American world.
A Warning from the Past
Undoubtedly there is an enormous technological and cultural gulf between the industrial economies of the contemporary European Union and a world of late Antiquity in which economic life in the fifth and sixth centuries was overwhelmingly dependent on agricultural production. Yet just as EU leaders are under increasing pressure to decide whether to preserve, replace, or discard symbols of US power, East Roman emperors in Constantinople were faced with a stark choice between consolidating their position around an Eastern Mediterranean core or seizing control of territories that had once belonged to the Western Empire. For successor states struggling to overcome the chaos left behind by a fallen hegemonic power, the strategic failures of Emperor Justinian’s reign should act as a warning to those who might hope to chase the glories of the past.
While EU policymakers might look back over the last two decades and ask themselves whether they had been too complacent about early signs of dysfunction within the US political system, the leadership of the Eastern Empire often assumed that the old status quo might be sustainable until the collapse of their Western partners in the 440s became too obvious to ignore.
Faced with military threats from the Persian empire on their Eastern border and instability on their Balkan frontiers, administrators and generals in Constantinople were too preoccupied with securing the survival of their version of the imperial system in the East to devote stretched resources to a last-ditch attempt to saving their allies in Rome. In the decades following the Western Empire’s final collapse in 476, the rulers of the East Roman Empire signaled their acceptance of new geopolitical realities by negotiating trade and diplomatic agreements with emerging powers in the West.
This pragmatism in Constantinople toward a post-Roman world in the West reflected an awareness of the East Roman empire’s vulnerability to economic instability and security threats along its borders. In a world that in 600 years had changed radically from the Mediterranean geopolitical order that had once enabled the rise of the Roman Republic, the first generation of East Roman leaders after the fall of the Western Empire focused on bolstering administrative and military resources needed to defend territories under their control rather than seeking territorial expansion. Within less than 50 years after the fall of Rome, these efforts at reform and renewal radiating outwards from Constantinople had secured the Eastern Roman Empire’s status as the most powerful geopolitical actor around the Mediterranean.
A Strategic Trap
By the early sixth century, however, this resurgence of East Roman power tempted a new generation in Constantinople under the leadership of Emperor Justinian to seek the restoration of the old imperial order in the West. Inspired by the boundless ambition of Augustus, Trajan, and other emperors that ruled Rome at the height of its power, Justinian pursued campaigns of reconquest that managed to bring Italy, North Africa, and Spain under Constantinople’s control after decades of relentless warfare. Yet what initially seemed to be a restoration of ancient glory gradually became a strategic trap, sucking in resources that Constantinople could not afford to use up in conflicts that brought the East Romans close to collapse by the early seventh century.
Even with the immense cultural distance between 21st-century Brussels and late Antique Constantinople, the Justinian Trap that brought the Eastern Romans a brief illusion of restored imperial glory at the expense of long-term resilience contains crucial lessons for EU policymakers faced with growing dysfunction among their own Western partners in Washington.
Just as the conquests of the Roman Republic were enabled by a specific set of geopolitical circumstances that could not be restored 600 years later, so the emergence of US hegemony was the product of a convergence of economic and military structural trends during the 1940s that the EU, China, or other aspiring great powers cannot recreate in the 21st century. Rather than succumbing to a Justinian Trap of trying to restore the greatness of an imperial order whose inability to adapt to change brought about its collapse, the EU should look at how Justinian’s predecessors adapted to new geopolitical circumstances by strengthening the economic prosperity and military resilience of their territorial core.
In a technologically networked world in which global power is projected through economic structures as much as military prowess the EU also needs to be aware of the risks of falling into a Justinian Trap when it comes to economic policy. Signs that Americans are no longer willing or able to sustain a hegemonic role are already fueling doubts about whether a global economic system underpinned by the dominance of the dollar and US Treasury bonds can remain intact. Even if the EU develops collective bonds that provide a safe haven for investors after the US market collapses, a post-American world in which China, India, and other states are equally crucial actors would mean that a growing systemic role for eurobonds and the euro as a reserve currency would still never match the dominance Washington achieved at the height of its power.
These multipolar dynamics would also affect the extent to which Europeans could shape a new trade system if the indiscriminate use of tariffs by President Trump leads to the collapse of current market structures. Though the EU, the United Kingdom, and Turkey would be a powerful node of global manufacturing and services, their level of interdependence with China, India, and other market actors would mean that a restructuring of global trade would need coordination between multiple geoeconomic powers. By contrast, any European attempt to restore a trade system that sustained US dominance until the 2010s would only alienate key trading partners and end in chaotic failure.
A Post-American World
The need to avoid stumbling into a Justinian Trap by emulating unsustainable American models would also be a crucial factor in efforts to build a new system to of collective global security. Though the EU and its partners have the industrial and military foundations needed to achieve dominance around Europe and the wider Mediterranean region, any effort to project power into parts of the world in which China, Japan, Brazil, and India along with at least two dozen other military and economic powers have their strategic center of gravity would only waste European resources that are needed to manage challenges closer to home. Rather than repeating Justinian’s mistake by engaging in a futile effort to emulate a model that no longer matches contemporary strategic realities, the EU will need to work with geopolitical partners from around the world to develop sustainable multipolar frameworks for stability and growth through shared institutions like the United Nations.
For all these signs of a potentially terminal crisis of American power might be imminent, the US still has immense economic and military sources of strength that could prevent its geopolitical decline. Yet as damage inflicted by President Trump’s culture war against his own state and society begins to build up, the risks that American hegemony might experience the same slow decline and sudden fall experienced by so many of its imperial predecessors are becoming difficult to ignore. If Europeans are to flourish in a post-American world, then they need to remember how chasing past glories became an unsustainable trap for Justinian’s successors and have the courage to imagine a different future.
Alexander Clarkson is lecturer in German, European, and International Studies at King’s College London.
