Europe's Plan B for NATO: The Historical Turning Point of the Transatlantic Security Architecture

The European NATO member states are accelerating the development of an unprecedented emergency plan to ensure the continent's defense capability in the event of an American withdrawal from the alliance structure. As reported by the Wall Street Journal on April 15, 2026, citing high-ranking diplomatic circles, Germany — a long-time opponent of a purely European defense architecture — has fundamentally changed its position and moved the plan into the practical implementation phase. This development marks a historic turning point in transatlantic security policy, the significance of which cannot be overstated.

The plans, which were first outlined last year and gained significant momentum following President Trump's threats to annex Greenland and his criticism of allies in connection with the Iran conflict, envision the creation of a "European NATO." Specifically, this involves transferring existing NATO command structures to European leadership, filling key positions with European officers, and gradually replacing American military equipment with European systems. The discussions are not taking place in official alliance meetings but are being advanced informally in side discussions and during dinners in NATO settings — an indication of the sensitivity of the undertaking.

The background to this development is the profound uncertainty among European governments regarding the reliability of the United States as a security guarantor. The doctrine outlined in the US National Defense Strategy 2026, which states that European countries should take primary responsibility for their conventional defense while Washington focuses on homeland security and containing China, has reinforced the impression in European capitals that the American nuclear umbrella can no longer be considered guaranteed. While the ideal scenario from a European perspective remains the continued presence of the US in NATO while transferring defense-capable tasks to Europeans — the emergency planning makes it clear that one can no longer rely on this optimum.

The defense spending of European NATO allies and Canada is experiencing impressive growth rates. According to the Atlantic Council, which published its updated defense spending tracker on April 9, 2026, European allies and Canada increased their defense spending by about 20 percent in 2025 compared to the previous year — the second consecutive year of such an increase. For the first time in NATO's history, all allies now exceed the previous target of two percent of gross domestic product. At the summit in The Hague the previous year, allies agreed on the ambitious target of five percent of GDP for defense and defense-related spending, and the current figures suggest that European countries are taking this target more seriously than many observers had expected. Particularly noteworthy: Norway has become the first European country to surpass the United States in per capita defense spending.

However, the capability gaps that need to be closed are still considerable. European officials identify three key areas where the continent lags technologically and industrially behind the United States: anti-submarine warfare capabilities, space reconnaissance, and air refueling systems. These domains are essential for credible deterrence against Russia, and replacing them with European solutions will take years, if not decades. The nuclear component poses the most difficult problem: Without the American nuclear arsenal and the system of nuclear sharing, Europe loses its strategic deterrent capability, and discussions about a European nuclear solution — possibly led by France and the United Kingdom — are still in their infancy.

At the same time, Turkey is signaling its intention to elevate its role within the new European security architecture. Defense Minister Yaşar Güler stated on April 9 at a conference of the SETA Foundation in Istanbul that Turkey is no longer a flank state on the southeastern periphery of NATO, but a central ally capable of ensuring security across the entire European theater. These statements, made ahead of the NATO summit in Ankara in July 2026, signal Ankara's ambitions to play a leading role in reshaping the alliance structure. Turkey possesses significant leverage with the second-largest conventional military potential within NATO, even though relations with individual European allies remain strained.

NATO Secretary General Mark Rutte has meanwhile urged European governments to make concrete commitments within days to secure the Strait of Hormuz — a sign that the operational reality of NATO, despite all strategic realignment, continues to be shaped by acute crises. The intertwining of the Iran issue with the transatlantic stress test shows how much the strategic and operational challenges for the alliance overlap.

The upcoming NATO summit in Ankara will be a litmus test for the future of the transatlantic alliance. European allies must demonstrate that their armament efforts are not only impressive on paper but can be translated into operational capabilities. The emergency planning for a Europe without American protection may seem like pragmatic caution, but it carries the risk of a self-fulfilling prophecy: The more resolutely Europe prepares for the eventuality without the US, the more likely that eventuality becomes. The question of whether the transatlantic partnership will continue in a new, asymmetric form or ultimately break apart will be decided in the coming months.