LISBON—As NATO leaders prepare to gather in Ankara this summer, the Alliance finds itself in a familiar strategic posture. Its attention remains fixed on its eastern flank, where Russia’s war against Ukraine continues to shape defense spending, force posture, and political messaging. That focus is necessary. But it is no longer sufficient.

NATO was not designed as a single-axis Alliance. From its founding, it was shaped by geography that ran from Norway’s high north through the Mediterranean to the Atlantic approaches. 

During the Cold War, southern allies such as Portugal, Italy, Greece, and Turkey played a quiet but indispensable role. They anchored sea lanes, air corridors, and forward logistics that linked North America to Europe. 

At the time, the security of the Atlantic Ocean was assumed rather than debated. In part, that might explain why it is so easily taken for granted now.

NATO’s southern blind spot

Today, however, vulnerabilities along NATO’s southern flank are accumulating faster than strategy is adapting. Maritime insecurity, hybrid threats, undersea infrastructure risks, and growing competition in the Atlantic are stretching an Alliance still organized around Cold War geography. 

At the 2024 NATO Summit in Washington, DC, allied leaders acknowledged this imbalance. The summit produced a Southern Neighborhood Action Plan and elevated the idea of a 360-degree approach to collective defense. NATO also appointed a special representative for the southern neighborhood and formalized workstreams on counterterrorism, maritime security, and the protection of critical undersea infrastructure. 

Since then, progress has been real but modest. Senior officials have met. Partner dialogues have been launched. The southern flank is discussed more often. But it is still resourced and prioritized unevenly—and nowhere is that gap clearer than in the Atlantic.

Russia and China extend their reach into the Atlantic

Not only has Russian naval activity in the Atlantic expanded—so has China’s footprint. Chinese state-owned firms have quietly acquired stakes in Europe’s busiest ports, including majority control of Piraeus, Valencia, and Zeebrugge. HMN Technologies, the rebranded successor to Huawei Marine Networks, has built or upgraded at least ninety submarine cable systems that carry the bulk of transatlantic internet and financial data traffic. 

At the same time, dozens of Chinese research vessels have been mapping the ocean floor across strategically sensitive corridors—part of the growing maritime threat picture that prompted NATO to establish a dedicated Maritime Centre for the Security of the Undersea Infrastructure. As the Alliance is beginning to recognize, undersea infrastructure could be a core vulnerability going forward—and will be vital to military mobility and civilian resilience.

Luckily, there is one NATO member state that can help strengthen the Alliance in both areas: Portugal.

Lisbon could become a key partner in allied security planning

While Portugal remains underappreciated in both NATO and US strategic calculus, its location, infrastructure, and political reliability make it one of the few allies positioned to address the challenges on the Alliance’s southern flank. 

For one, Portugal’s Azores islands sit astride key air and maritime routes linking North America, Europe, Africa, and the Middle East—and Lajes Air Base, located on Terceira Island, has long functioned as a critical logistical hinge for NATO operations. From the Yom Kippur War through the post-9/11 era, this base has supported transatlantic deployments, maritime surveillance, and crisis response, serving as a central Atlantic hub. 

Even as the US military footprint fluctuated, the strategic logic of maintaining such outposts has not disappeared. In fact, it has only grown stronger as NATO confronts threats that are harder to see but easier to disrupt.

Moreover, major Portuguese political parties on the left and the right have maintained consistent support for NATO. This fact was once again underscored in Portugal’s 2024 legislative election, where the center-right Democratic Alliance narrowly edged out the center-left Socialists. As Portuguese Ambassador to the United States Francisco Duarte Lopes explained at the time, “Since we reinstated democracy in the 1970s, Portugal’s tradition has always had continuity in the strategic direction of our foreign policy.” The country’s governing direction remains firmly embedded in NATO, skeptical of concepts that weaken transatlantic defense, and committed to multilateral cooperation as a force multiplier rather than a constraint.

For the United States, this matters. Alliances depend on predictability as much as capability. From defense cooperation to trade and investment, Portugal remains a steady Atlantic partner that treats the transatlantic relationship as critical infrastructure. Portugal’s Exclusive Economic Zone in the Atlantic Ocean is one of the largest in Europe, which makes Lisbon a crucial strategic partner in Atlantic security. 

From recognition to implementation

The upcoming Ankara summit offers NATO an opportunity to integrate the Atlantic fully into Alliance planning. Building on the Southern Flank Action Plan, that effort should include expanding joint naval operations, strengthening maritime domain awareness, and explicitly linking Portuguese infrastructure to NATO’s deterrence and resilience architecture. These are not symbolic gestures. They are overdue adjustments to strategic reality.

NATO’s credibility rests on its claim to provide security from all directions. Ankara will rightly focus on deterrence, defense spending, and Alliance unity. It should also recognize that NATO’s southern flank—and the Atlantic that binds it together—is no longer peripheral to those goals. Portugal, an Atlantic nation with outsized strategic value, should be central to how the US and its allies translate that recognition into action.

Ignoring the southern flank has never made NATO safer. In today’s Atlantic and Mediterranean security environment, doing so makes the Alliance thinner, slower, and more exposed than it can afford to be.