• NATO still anchors transatlantic security despite rising tensions, experts say
• 2026 predicted to be decisive for Europe’s security, political integration

ATHENS / BRUSSELS

Transatlantic relations entered a more uncertain phase in 2025 as Washington reassessed its global priorities, forcing Europe to face difficult choices over security, energy policy, spending priorities and political integration.

The strain became increasingly visible over the year. At the Munich Security Conference in February, US Vice President JD Vance delivered a scathing critique of Europe, questioning whether current European values still warranted American defense commitments. He accused European governments of media censorship, political conformity and the erosion of democratic norms.

Tensions deepened with new US tariffs on EU imports and again in December, when Washington released its latest national security strategy. The document devoted limited attention to Europe and painted a bleak picture of the continent’s future, warning it could face “civilizational erasure” if current regulatory and migration trends persist.

“The split is final,” declared French daily Le Monde.

Ian Lesser, head of the Brussels office of the German Marshall Fund and chair in transatlantic affairs at the College of Europe, told Anadolu that US unpredictability over the past year has heightened European concerns across security, trade and diplomacy.

“Many people imagined that somehow this second Trump administration would be isolationist,” Lesser said. “It is not isolationist at all. In fact, it is quite activist on the international scene.”

He cautioned that Europe remains far from capable of defending itself independently.

“Protecting Europe without predictable American participation is very challenging,” he said. “It will take years, perhaps many years, for Europe to be in a position to deter credibly without the American connection.”

US presence unlikely to disappear

Despite mounting strain, Lesser said the US commitment to Europe’s security has not collapsed.

“I think despite a lot of concerns, in some ways the NATO element has been more stable than many other aspects of the transatlantic relationship,” he said, pointing to continued US leadership roles within NATO and legislative constraints on large-scale US troop withdrawals from Europe.

A complete US withdrawal from European security is neither realistic nor desirable, he added.

"I think the sensible approach, and I think it is the approach Europe is taking, is to plan for a less and less predictable American presence in European security,” he said. “But not a presence and participation that goes to zero.”

Rather than building parallel security structures, he argued Europe should strengthen its role within NATO. “The best way to do this would be to use the capacity that already exists,” he said.

Lesser also pointed to political and cultural constraints within Europe, including public reluctance to accept the costs and risks of military power.

"Europeans are much more comfortable talking about new defense spending in terms of industrial policy than actual defense policy,” he said.

On nuclear deterrence, he warned that a credible European security posture remains difficult without US conventional forces on the ground.

"It’s very difficult to imagine an American strategic nuclear umbrella for Europe without a parallel presence on the ground,” he said. “There needs to be a ‘trip wire’ for it to be credible to Russia.”

Europe cannot afford to 'go alone'

Spyros Blavoukos, head of the EU Institutions and Policies Program at the Hellenic Foundation for European and Foreign Policy and professor at the Athens University of Economics and Business, said Europe now faces decisions that could reshape its future security architecture.

Unlike the shock of 2016, he said, a second Trump term was broadly anticipated in Europe, allowing EU institutions time to prepare.

"It was expected that there would be some turbulence," he said, pointing to early disruptions from trade tensions and renewed protectionist policies.

Europe’s strategy, Blavoukos said, has been to balance Washington’s transactional demands while ensuring continued US engagement in European security.

“At this point, we cannot afford to go alone,” he said. “We are gaining time to be better prepared in a future recalibration.”

He added that Washington’s priorities are increasingly shaped by containing Russia and managing broader global rivalries – sometimes diverging from European preferences.

Time for 'critical decisions'

Blavoukos warned that Europe must now make difficult trade-offs, including reducing energy dependence on Russia even if it means shifting reliance to the United States.

"We wanted peace, stability. We wanted economic competitiveness, which was based on cheap energy imports from Russia. We wanted to have the security umbrella of the US,” he said. “You need to choose. You need to make some very critical decisions.”

He said 2026 could bring heightened political and social tensions as governments balance rising defense spending against social welfare priorities.

“It’s a make-or-break situation,” Blavoukos said, arguing that failure to deepen political and security integration now could leave Europe more vulnerable in future crises.

At the same time, he cautioned that public opinion across the EU remains hesitant about deeper integration and military commitments, putting additional pressure on policymakers to act decisively.