Since the end of World War II, the security of the European continent has been closely tied to the strength of the transatlantic relationship, with the alliance with the United States serving as the primary guarantor of regional and geopolitical stability in the face of major threats, particularly from the East. NATO became a security umbrella covering both Western and Eastern European countries, allowing Europe to focus its efforts on economic development and political integration, while the United States remained the key military and strategic actor.
However, the traditional equation of European security began to crack with Donald Trump’s return to power in January 2025. His second term came with fundamental shifts in Washington’s global commitments. It became clear that the new U.S. administration’s approach is based on reducing foreign military involvement and redefining national interests through narrower, more pragmatic frameworks—turning “security protection” into a negotiable commodity rather than a firm strategic commitment. This shift reopened a deep debate within European circles: What is the fate of European security amid eroding trust in the American partner? And does Europe have the ability to build sustainable self-security in the face of escalating internal and external threats?
At this critical moment, the European continent stands at a historic crossroads, where it is no longer possible to return to old formulas, nor to continue relying on Washington’s erratic decisions. It has become necessary to rebuild the foundations of European security with a vision that is more independent, inclusive, and adaptive to the changing global order.
1. American Strategic Ambiguity and the Decline of Alliance Reliability
Trump’s second term represents a conceptual reversal in the United States’ relationship with its allies. The beginning of his presidency was marked by a tougher stance toward NATO, along with statements questioning Article 5 of the NATO Charter, which pertains to collective defense. Military aid and interventions became conditional on profit-and-loss calculations rather than geopolitical or historical commitments. This led to confusion in European circles, as the American umbrella was no longer viewed as an absolute security guarantee but rather as a shifting political choice.
This transformation has forced European countries to reassess the structure of their security relationships and to ask fundamental questions about how to deal with a strategic ally who is increasingly inward-looking and less willing to defend others—even long-time partners.
2. Rising Russian Threats and Incomplete Deterrence Strategy
Russia remains the biggest geopolitical challenge to Eastern Europe, especially after the consequences of the Russia–Ukraine war, which exposed the fragility of total reliance on Washington in managing major crises. Under Trump’s second term, fears are growing that American deterrence may be absent at a critical moment, encouraging Moscow to test NATO’s limits, particularly in the Baltic States or Poland.
The lack of clear and assured American deterrence, along with shifts in the military balance of power, revives Cold War-era scenarios—but without the stable deterrence frameworks that existed in the 20th century. In this sense, European security finds itself exposed to a traditional adversary skilled at exploiting political and military gaps within the Western alliance.
3. The Crisis of Building Self-Security and the Challenges of Strategic Autonomy
Despite repeated calls for European “strategic autonomy,” the reality reveals structural complexities that hinder the achievement of this vision. Differences among European countries in terms of defense capabilities, perceptions of threats, and internal political divisions all obstruct the building of a unified security system. However, the pressures from Trump’s second presidency have become a compelling incentive for the European Union to push forward joint defense projects, establish unified military industrial structures, and activate the European Defence Fund.
Still, this path remains in its early stages and requires unprecedented political will, long-term investments, and overcoming the national sensitivities that have long hindered effective European defense coordination.
4. Non-Traditional Threats and Scenarios of Structural Chaos
Europe currently faces multi-dimensional security challenges that are not limited to direct military threats. These include cyber security, disinformation, irregular migration, attacks on vital infrastructure, as well as climate change and pandemics. These threats require flexible and unified response systems, which contrast with a political environment marked by the rise of populism and declining consensus within the European Union.
With the retreat of American leadership, dealing with these threats has become a purely European responsibility. This demands a redefinition of comprehensive security strategy and an expansion of the concept of protection to include the digital space, economy, and social infrastructure—alongside traditional military defense.
5. The New International Order and Multipolar Competition in the European Space
Trump’s second presidency coincides with the growing influence of China and Russia in the European arena. Beijing has begun to strengthen its investment and technological presence through the Belt and Road Initiative, while Moscow has expanded its hybrid tools to influence the internal politics of several European countries. Meanwhile, regional powers such as Turkey and Iran are reshaping their roles, further complicating the overall security landscape.
Amid this multipolar competition, Europe becomes more vulnerable to strategic penetration unless it strengthens its internal resilience, builds alternative alliance networks, and reinterprets its geopolitical geography with greater realism and independence.
Between the Legacy of the Cold War and the Limits of the Future: European Security on the Edge of Transformation
Europe can no longer cling to the security model born in the Cold War and nurtured under American patronage. Trump’s second term is a revealing moment that goes beyond immediate policies—it forces the Old Continent to confront a harsh reality: Europe’s security must be built in Europe, for Europe, and by Europeans themselves.
This historic moment is not merely a crisis but an opportunity for restructuring and forming a new strategic awareness that places European interests at the heart of decision-making and grants the continent the capacity to protect itself in a world that no longer recognizes historical guarantees, but values the power of self-action and the flexibility of renewed alliances.
The future of European security is no longer tied solely to the White House’s stance. It now depends on Europe’s ability to overcome division, invest in unity, and turn the fear of abandonment into a comprehensive project for sovereign independence in security, defense, and geopolitical decision-making.
