One of the most pressing questions facing the world order today concerns the nature of transatlantic security. This issue is not only critical because of its foundational role in the previous world order but also due to the anticipated fractures its potential unravelling could bring.
The transatlantic security architecture has always carried an implicit economic dimension, which now appears to be contributing to the erosion of guarantees around peace, stability, and security. Today, transatlantic security stands at a crossroads. Can NATO and the evolving EU-US relationship overcome growing divergences? For decades, NATO and the broader transatlantic partnership have served as the backbone of Western security, with America's influence casting a long shadow.
However, shifting geopolitics, emerging threats, and diverging priorities in Washington are beginning to reveal daylight between the two sides of the Atlantic—and perhaps a few cracks in the armour of their once-unified vision of security.
Today, transatlantic security is undergoing a fundamental realignment within the broader landscape of global security partnerships. Its roots run deep, shaped by more than 75 years of history since the end of World War II. The original purpose of transatlantic security was to prevent the recurrence of world wars and to guard against the domination of any single power.
To that end, a rules-based international order, led by global institutions, was established to govern the post-war world. Since then, consistency and assurance have remained central to the transatlantic security framework. However, the governance structures that accompanied this liberal order often operated to the disadvantage of the Global South and the wider developing world.
As Asia began to rise—most notably through the economic and military ascendance of China and India—the global balance of power has shifted, prompting a natural recalibration of the old world order.
Even though the idea of transatlantic security seems shaken, beneath the surface, Europe and America remain fundamentally intertwined—military cooperation continues, and arms supplies persist. Nowhere is this relationship more evident than in the technological and defence assistance the United States provides to its European partners.
For instance, it is largely due to robust US-provided aerial defence systems that Ukraine has been able to fend off Russian ballistic missile attacks. However, there has been a marked shift in US intent regarding continued arms and financial aid to Ukraine, especially under Donald Trump, who argues that European security should now be Europe’s responsibility.
Early signals from Washington suggest a possible drawdown in support, with expectations that Europe must “get its act together.” This messaging has been received in two divergent ways. First, some in Europe now view America as an increasingly unreliable ally. Second, others interpret the shift as a necessary wake-up call—an opportunity for Europe to take ownership of its security and step up its support for Ukraine.
Trump’s central demand from European partners is that they should pay their fair share, particularly by raising defence spending as a percentage of GDP.
The American rationale for stepping back from transatlantic security commitments rests on the idea that if Europe takes on more responsibility, the US can redirect its focus to other strategic theatres—most notably, the Indo-Pacific and the growing competition with China.
As for evidence, recent visits by top US officials to the Indo-Pacific Command (INDOPACOM)—including Director of National Intelligence Tulsi Gabbard and Defense Secretary Pete Hegseth—underscore the Trump administration’s continued and unwavering focus on countering China in the region.
This recalibration is also aimed at a domestic audience that brought Trump to power on a platform of prioritising American interests above all.
The ongoing trade war between China and the United States may represent the economic culmination of one of the most significant great power rivalries of the 21st century. A strategic unravelling of this confrontation appears to be underway, particularly as China has defied U.S. warnings not to retaliate.
With tariffs and counter-tariffs reaching as high as 125 percent, the current trade dynamic is increasingly unsustainable, especially for China, given its disproportionately high export dependence on the U.S. In this context, the fundamental restructuring of global connectivity routes and supply chains, the relocation of manufacturing bases, and the quest for strategic influence across key geographies are likely to define the contours of the emerging world order.
The structural continuity of the previous world order—anchored by the transatlantic security alliance—is now being tested by growing calls in Washington for economic decoupling from European partners. The full extent of the resulting security and economic implications remains to be seen. Ultimately, the direction Europe takes in the long term will be crucial in determining the future shape and resilience of transatlantic security.
Europe’s response to American pressure will likely involve a gradual readjustment of its economic and security dependencies on the United States. However, it is unlikely that Europe will take any abrupt action in response to America’s increasingly isolationist stance.
What will be crucial, though, is how Europe reorients its strategic and economic relationships with other parts of the world—particularly with China and across the Indo-Pacific. This realignment will play a central role in shaping the future trajectory of transatlantic security.
Should Europe’s response to U.S. pressure lead to deeper engagement with China and/or a form of risk mitigation with Russia, the very concept of collective security would undergo a profound transformation. Ultimately, the most significant external factor that could reshape transatlantic security may be the emergence of a grand bargain between Washington and Moscow—early indications of which may already be beginning to surface.
