Soldiers in helicopters take part in NATO’s STEADFAST DART 26 exercise in Putlos, Germany, on February 18, 2026.
Fabian Bimmer / POOL / AFP
For decades, NATO’s greatest strength has been political cohesion: the assumption that when the United States defines a strategic threat, its European allies broadly follow. The war with Iran is testing that assumption. The Alliance’s military structures remain intact, but the political consensus behind them is visibly fraying. Washington sees Iran as a strategic confrontation that demands decisive action. Across parts of Europe, however, governments remain more concerned with Russia, continental security, and the risk of another prolonged Middle Eastern conflict.
From Brussels, the feeling is not one of NATO’s immediate collapse. Its military structures are functioning, deterrence remains operational, and no one has formally questioned Article 5. But the political climate has changed. The tone is harsher. Trust is not what it used to be. And old questions—about sovereignty, dependence, and strategic loyalty—have once again taken over the headlines.
The war with Iran is not militarily breaking the Alliance but testing its political cohesion—a cohesion already strained by the war in Ukraine, Washington’s confrontational rhetoric during the Trump era, and Europe’s persistent difficulty in translating political commitments into concrete military capabilities.
One of the roots of the disagreement is that Europeans and Americans are not reading the same strategic map.
For President Trump and much of his circle, Iran represents a major long-term challenge: a regional power capable of destabilising the Middle East, threatening Israel’s position, and potentially acquiring nuclear weapons in the medium term. From this perspective, deterrence must be decisive and hesitation risks being interpreted as weakness—a logic that has long shaped American strategic thinking.
Across much of Europe, the perception is different. Russia remains the immediate and geographically relevant threat. Hybrid warfare, energy vulnerability, migration pressures, and the cohesion of European societies dominate the security agenda.
This divergence does not necessarily imply European naivety or American recklessness. It reflects different geopolitical realities. But when threat hierarchies diverge inside an alliance, friction is almost inevitable—especially within a bloc of 32 members facing very different security environments.
Spain has been among the most explicit critics of escalation. Pedro Sánchez’s government has warned of wider destabilisation and signalled reluctance to allow Spanish territory to be used for offensive operations. France has adopted a more nuanced balance, expressing concern about the unilateral scale of the strikes while maintaining diplomatic channels and preserving its strategic autonomy. Canada has similarly emphasised prudence and international legitimacy.
None of these governments has questioned NATO’s collective defence commitments or broken with Washington. What their positions illustrate, however, is a broader pattern: allied solidarity does not necessarily translate into unconditional alignment with American strategic decisions.
This tension is not entirely new. It recalls the “with us or against us” dynamic that emerged during the post-9/11 war on terror—an approach that risks complicating Western cohesion at a time when China is carefully observing the divisions within its principal strategic rival.
German Chancellor Friedrich Merz has taken a more clearly Atlanticist stance. Berlin remains acutely aware of its structural dependence on the American security umbrella, making open confrontation with Washington strategically unwise. Merz has reiterated Germany’s commitment to increasing defence spending and strengthening transatlantic cooperation, and he has not hesitated to criticise Madrid’s position.
The United Kingdom under Keir Starmer occupies a more delicate position. London has acknowledged that Europe must assume a greater share of the defence burden—a longstanding demand from Washington—and has allowed limited cooperation in defensive terms.
However, Britain did not participate in the initial strikes and has sought to preserve allied cohesion. From Downing Street, this is presented as a balanced approach. From the White House, it may appear as insufficient loyalty. If even London hesitates to follow Washington automatically, the depth of the transatlantic consensus can no longer be taken for granted.
The Anglo-American special relationship has always carried symbolic weight. In times of conflict, symbols can matter as much as operational decisions.
On the military level, NATO continues to function. Air defence systems remain on alert, intelligence sharing continues, and command structures operate normally.
But alliances do not rest on technical capabilities alone. They depend on political trust.
The growing overlap between strategic disagreements and economic pressure represents a notable development. Trade threats and economic leverage are increasingly being used in disputes that traditionally remained within the security domain.
At the same time, European governments are conscious of public opinion. The memory of Iraq and Afghanistan remains strong. While support for NATO as a framework for collective defence remains robust, enthusiasm for new and potentially prolonged military involvement in the Middle East is far more limited.
The result is a delicate balance: operational cooperation combined with political caution.
If these dynamics persist, NATO could gradually evolve toward an informal two-speed structure. One group of allies would align closely with U.S. global campaigns, while another would limit its involvement largely to territorial defence and regional stability.
All would remain formally committed to Article 5, but the political scope of the Alliance would narrow. NATO would cease to function as a strategic community with a shared global outlook and instead become a framework for more selective cooperation.
Such a transformation would not necessarily mean the end of the Alliance. But it would represent a fundamental shift in its character.
The United States will remain indispensable to European security for the foreseeable future. The question is whether the political consensus that has long sustained the Atlantic alliance can adapt to a world in which American and European strategic priorities increasingly diverge.
