The Trump administration’s newly released 2025 National Security Strategy (NSS) symbolises the most dramatic recalibration of American foreign policy in decades. At its core lies a revival, almost verbatim, of the Monroe Doctrine: the idea that the United States should prioritise dominance in the Western Hemisphere while minimising long-term entanglements elsewhere, including in Europe. Though references to the 19th-century doctrine appear modernised, the strategic logic is unmistakably familiar: the United States, once it was heard in every corner of the world, be it the Middle East or Asia, intends to centralise power at home, exert control over its near abroad, and scale back global commitments that it considers wasteful, ideologically misguided, or strategically outdated.
The new NSS also presents a sharply critical portrait of Europe. In language unusually confrontational for an allied relationship, the document frames the European Union as a region suffering from demographic decline, policy fragmentation, weak defence capacity, and a loss of ‘civilisational self-confidence’. These characterisations serve not merely as rhetoric but as justification for Washington’s shifting priorities. In effect, the administration argues that Europe no longer possesses the strategic vitality to justify deep American involvement in its security affairs, particularly in prolonged conflicts such as the Russia-Ukraine war.
This repositioning comes at a sensitive moment. The European Union remains a principal funder and political backer of Ukraine’s defence, while Kyiv continues to set ambitious military and diplomatic expectations for the West. Yet the United States, under its recalibrated doctrine, appears increasingly inclined to end the conflict rather than extend it indefinitely. The tension between these approaches is now becoming one of the most consequential fractures in transatlantic relations since 1945.
The updated NSS should be read, first and foremost, as a vision of American self-containment. It rejects the longstanding assumption that the United States must serve as Europe’s strategic stabiliser. Instead, it prioritises border security, economic nationalism, and hemispheric consolidation. Policy architects in Washington argue that the globalised commitments of the post-Cold War period have outlived their usefulness and drained American political capital, economic strength, and military attention. Within this framework, allies are evaluated through a more transactional lens: whether they advance US interests rather than whether they share US values. For Europe, this shift is profound. Unlike during the Cold War, when Europe represented the ideological frontier against the Soviet Union, today’s NSS treats the continent as a region that is drifting from American strategic priorities, particularly on issues such as climate policy, migration, and regulatory governance. This provides justification for Washington’s pivot away from large-scale European engagements and back towards its historical sphere of influence.
Nowhere is this strategic recalibration more visible than in the Russia-Ukraine war. While past administrations perhaps treated the defence of Ukraine as a cornerstone of the rules-based order, the new NSS signals a decisive departure. Washington now frames the war less as a global struggle for democracy and more as a regional conflict whose long-term dynamics must be managed rather than endlessly funded. This does not imply sympathy for Russia. The NSS reiterates that Moscow remains a strategic competitor with revisionist intent. Yet the document recognises what Europe has been reluctant to acknowledge: that Ukraine cannot achieve its maximalist war aims on the battlefield alone, and that the conflict has placed disproportionate economic and political pressure on Western societies. The administration appears intent on shifting Ukraine toward a negotiated settlement, an outcome the EU remains deeply hesitant to embrace. For Brussels, the conflict is existential; for Washington, it is increasingly peripheral. This divergence between American pragmatism and European principled resolve could reshape NATO, defence cooperation, and the future of European security architecture.
The NSS’s sharp tone towards European allies is unprecedented in its candour. It suggests that Europe is failing to maintain credible defence capabilities, is overly reliant on American security guarantees, and is distracted by internal ideological battles. The reference to ‘civilisational erasure’, a phrase strongly criticised by European leaders, has fuelled debate about whether Washington is moving ideologically closer to Europe’s far-right nationalist movements. The EU’s response, meanwhile, emphasises unity, resilience, and continued support for Ukraine. Yet there is a growing recognition across European capitals that the United States may no longer act as Europe’s ultimate security guarantor. Several European political leaders have already urged accelerated defence spending, expansion of domestic arms production, and development of autonomous security capacities. Trump’s NSS has therefore exposed Europe’s strategic vulnerability: despite its economic weight, the EU has not matured into an independent security actor. If the United States truly intends to deprioritise Europe, the EU will face the first real test of its ability to defend its neighbourhood without relying overwhelmingly on American leadership.
The US pivot toward the Western Hemisphere leaves a geopolitical vacuum in Europe and Eurasia. Russia, despite its battlefield losses, continues to position itself as a long-term challenger to European security. If Washington reduces strategic involvement, the Kremlin may believe the West is losing resolve-potentially emboldening further destabilising actions. China, too, will treat this vacuum as an opportunity. Beijing has already deepened its ties with Moscow, expanded commercial influence in Central Asia, and strengthened Belt and Road engagement in Europe. If the USA retreats to its hemisphere, China will become the principal external actor shaping European and Eurasian dynamics. The NSS acknowledges these risks but suggests that the United States must prioritise threats closer to home and focus on domestic renewal. This marks a clear departure from decades of American grand strategy built on global equilibrium maintenance.
The United States has not abandoned Europe entirely. NATO remains formally intact, and Washington continues to support Ukraine, albeit with growing conditions. Yet the philosophical foundation of the alliance is changing. Values-based cooperation is being replaced with interest-based calculation. European leaders now face a stark choice: adapt to America’s new priorities or build sovereign capacities capable of sustaining European security independently. The revival of the Monroe Doctrine is not simply a rhetorical flourish. It signals a structural reorientation of US foreign policy that is likely to endure. Whether Europe can adjust to this new reality will determine the future of the transatlantic partnership. In a world where the United States turns inward, Europe will no longer have the luxury of strategic dependence. The era of unquestioned American leadership is ending, and Europe must now decide whether to respond with unity and ambition or risk fragmentation in an increasingly unstable global order.