Is NATO entering an era of transactional alliance politics?

By Sun Chenghao

The 2026 North Atlantic Treaty Organization (NATO) Summit, being held in Ankara on July 7 and 8, will formally focus on familiar issues: increasing defense spending, expanding defense production, strengthening security investment and continuing support for Ukraine. Yet beneath these agenda items lies a more consequential question: Is the logic of NATO itself changing?

For decades, NATO has presented itself as an alliance based on shared values, collective defense and strategic solidarity. The United States provided security guarantees to its European allies not simply as a bilateral transaction, but as part of a broader effort to sustain the Western security order. Burden-sharing disputes certainly existed, but Washington generally treated European security as a strategic public good.

That logic is now under growing pressure. Under US President Donald Trump's second term, Washington has become increasingly explicit in linking US security commitments to allied contributions. Defense spending, military infrastructure, participation in overseas operations, defense procurement and political support for US strategic priorities are increasingly being used to measure the "value" of an ally.

Ahead of the Ankara summit, NATO members are expected to reaffirm last year's commitment to invest 5% of GDP in defense and defense-related spending by 2035, while European allies and Canada continue to shoulder a growing share of military assistance to Ukraine. Security, in this sense, is no longer treated as an unconditional commitment. It is becoming a package with a price tag.

This does not mean that NATO's Article 5 commitment has disappeared. Nor does it mean that the alliance is about to collapse. But it does suggest that the internal operating logic of NATO is shifting. Collective defense remains the formal principle, while conditional security provision is becoming the practical reality.

In the past, shared values and common threats helped hold the alliance together. Today, these factors still matter, but they are no longer sufficient to guarantee unlimited US protection. Allies are increasingly expected to prove their relevance through higher defense spending, larger purchases of military equipment, stronger support for US deployments and greater alignment with Washington's global strategy.

This is the essence of a transactional alliance. NATO is not abandoning values altogether, but values are being subordinated to cost accounting. The alliance is not being dismantled, but it is being repriced.

Notably, this shift should not be understood merely as a product of Trump's personal style. It reflects a deeper structural change in US strategy.

Washington wants European allies to assume more responsibility for European security so that the US can devote more attention and resources to the Asia-Pacific and to great-power competition. Trump has made this approach more direct, more coercive and more transactional, but the broader demand for Europe to do more is unlikely to disappear even under a different US administration.

Indeed, NATO Secretary General Mark Rutte recently noted that European allies and Canada added well over $139 billion in defense spending in nominal terms last year, while emphasizing that Europe must continue assuming greater responsibility for the Alliance's defense.

For Europe, this shift creates both pressure and opportunity. On the one hand, higher defense spending will place additional strains on European governments already grappling with slow growth, fiscal constraints and domestic political fragmentation. Many European countries will find it difficult to sustain large increases in military expenditure without cutting social spending or triggering public resistance.

On the other hand, uncertainty surrounding US security commitments is also pushing Europe to strengthen its own defense capabilities. Efforts to expand defense industrial capacity, promote joint procurement and advance Europe's strategic autonomy have gained momentum precisely because Europeans increasingly recognize that reliance on Washington is no longer as politically predictable as before.

The future of transatlantic relations, therefore, is unlikely to be defined by simple rupture. The US still needs Europe as its most important network of allies, while Europe still depends heavily on US nuclear deterrence, intelligence, strategic transport, air and missile defense, and other high-end military capabilities. The two sides will remain closely connected.

What is changing, however, is the nature of that connection. For decades, the old model was based on a relatively stable division of labor: The US provided overarching security guarantees, while Europe contributed politically, economically and militarily within a US-led framework. Today, the emerging model is more conditional. It places greater emphasis on costs, deliverables and measurable contributions.

This will inevitably affect trust within the alliance. If security commitments are increasingly judged by payment and performance, allies may begin to question whether the US would still honor its commitments in a crisis. Smaller and more vulnerable members may worry that their security could be treated as negotiable. Larger European powers may accelerate their search for alternative defense arrangements. The result may not be NATO's disintegration, but it could be a more anxious, fragmented and less cohesive alliance.

The Ankara summit is therefore more than another debate about defense budgets. It reflects a broader transformation in alliance politics. When security is priced, loyalty measured and protection conditioned, collective defense becomes less a shared commitment and more a negotiated service.

From a broader international perspective, this trend also reveals the limitations of exclusive military blocs and bloc politics. In a world facing complex and interconnected challenges, security cannot be sustainably built on coercive burden-sharing, zero-sum rivalry or transactional protection. Countries ultimately need a more inclusive vision of common security, based on mutual respect, equal treatment and genuine multilateralism.

NATO may still speak the language of shared values. But the Ankara summit shows that its practice is increasingly shaped by the logic of transactions. The alliance may not falling apart. It is being redefined, and more importantly, it is being repriced.

Sun Chenghao is a senior fellow at the Center for International Security and Strategy (CISS), Tsinghua University, and a Munich Young Leader with the Munich Security Conference.