This commentary examines how the 90th anniversary of the Montreux Convention Regarding the Regime of the Straits highlights Türkiye’s legally grounded guardianship role in the Black Sea and its broader Constructive Eurasianism vision. It argues that reaffirming commitment to Montreux on 20 July 2026 is not a purely commemorative gesture, but a strategic reminder that a rules-based straits regime remains central to regional order under conditions of systemic uncertainty.[1]

The Legal Architecture of the Straits

Signed in Montreux on 20 July 1936, the Convention affirmed Türkiye’s full sovereignty over the Turkish Straits, treated as its internal waters, while establishing a differentiated passage regime for merchant and naval vessels.[2] For ninety years, Türkiye has implemented this regime with neutrality, transparency, and diligence in both war and peace, and the Convention has come to be recognized as one of the principal guarantees of peace, security, and stability in the Black Sea. In the context of the ongoing Russia–Ukraine war and the risk of spillover into the maritime domain, the continued validity and effectiveness of Montreux have once again demonstrated the lasting value of carefully calibrated international legal arrangements. In contrast to more recent maritime regimes shaped primarily by the United Nations Convention on the Law of the Sea, the Montreux framework has required no formal revision since 1936, yet has repeatedly proven adaptable in crises ranging from the Second World War to the present conflict in Ukraine.[3]

From a conceptual perspective, Montreux is a cornerstone of what AVİM has termed Constructive Eurasianism.[4] This approach rejects simplistic binaries between “the West” and “the East” and instead positions Türkiye as a stabilizing nexus that combines alliance commitments with strategic autonomy and regional responsibility.[5] The Straits regime illustrates a model in which sovereignty, legal predictability, and cooperative security interact: Türkiye exercises undisputed control over the Straits, including restrictive powers under Article 21, while preserving freedom of navigation for commercial shipping and maintaining a balanced framework for Black Sea and non–Black Sea navies.

Freedom of Navigation and Treaty Context

Recent debates risk distorting this legal and historical equilibrium in at least two ways. Some actors instrumentalize the language of “freedom of navigation” to press for looser interpretations of Montreux, overlooking the carefully negotiated tonnage, duration, and notification limits imposed on non–Black Sea fleets. Such proposals, however, tend to abstract ‘freedom of navigation’ from its treaty context and ignore that Montreux’s restrictions were precisely designed to prevent great‑power naval competition from turning the Black Sea into a permanent arena of bloc confrontation. Second, certain Eurocentric narratives continue to treat Türkiye’s implementation of the Convention as a technical detail rather than as a sovereign, normatively informed contribution to regional order. Such tendencies reflect broader patterns of conceptual inflation and selective memory that AVİM has long criticized in other fields, including debates on genocide, historical justice, and alliance politics.[6]

Türkiye’s Guardianship

A legally consistent reading of Montreux, however, underscores Türkiye’s role as a responsible guardian rather than as an obstructive gatekeeper. By rigorously applying the Convention’s provisions during successive crises, Ankara has provided all regional and extra‑regional stakeholders with a predictable framework that limits escalation and constrains unilateral power projection. This guardianship is not merely a technical function; it embodies a normatively charged understanding of the Black Sea as a basin whose stability depends on respect for littoral states’ sovereignty and the prevention of militarized experimentation by distant powers.

In this sense, the 90th anniversary statements by the Ministry of Foreign Affairs, reaffirming impartial, transparent, and diligent implementation as well as the enduring value of the Convention, should be read together with Türkiye’s broader foreign policy discourse on a changing world order.[7] Over the past decades, AVİM’s reports and commentaries on the legal regime of the Turkish Straits and on Black Sea security have consistently underscored this point, treating Montreux as a regional and global safety valve rather than a mere technical annex to Turkish foreign policyAs AVİM’s Constructive Eurasianism perspective emphasizes, the erosion of the post–Cold War liberal order has not eliminated the need for law and institutions; it has instead increased the premium on regionally anchored regimes that can withstand geopolitical turbulence. Montreux stands out as one of the rare instruments that has preserved its relevance without requiring constant revision, precisely because it embeds a balance between coastal security, great-power interests, and the commons logic of commercial navigation.[8]

Policy Implications

From a policy standpoint, three implications follow. First, Türkiye should continue to resist attempts to dilute or reinterpret Montreux through ad hoc political bargaining, insisting on a text‑based, precedent‑conscious application of the Convention. Second, regional and extra‑regional actors ought to recognize that challenging the Convention’s parameters under the guise of “modernization” could undermine one of the last effective stabilizing mechanisms in the Black Sea. Third, scholarly and policy debates should integrate the Montreux experience into wider reflections on cooperative security, maritime law, and the evolving geometry of alliances in Eurasia, instead of treating it as a narrow technical specialty.

On the 90th anniversary of its signing, Montreux thus appears not as a relic of interwar diplomacy, but as a living framework through which Türkiye exercises a principled guardianship of meaning and order in the Black Sea. Preserving this framework against conceptual distortion and geopolitical impatience will remain essential for safeguarding regional stability and for sustaining a balanced, constructive Eurasian role for Türkiye in the decades ahead.

*Picture: Republic of Türkiye Ministry of Foreign Affairs