Just as it eschewed declaring war on Ukraine—proclaiming, instead, a “special military operation”—Russia never officially announced a naval blockade of Ukraine. A declared blockade accompanying a declared state of war would have enabled Russia to, however abusively, stop and search any commercial vessels, turn back suspected ones and potentially seize Ukrainian vessels.
Russia has refrained from such actions thus far due to political-diplomatic and practical considerations. It conducts the naval blockade similar to the war on land on a de facto basis, and it enforces the blockade without having to fire warning shots or bump into ships (a Russian method seen in 2003, 2014 and 2018 in the Black Sea). Meanwhile, Russia is supplementing the naval blockade by attacking Ukrainian commercial ports from the air (see EDM, July 26).
On top of that, Russia frequently announces military exercises—in practice, temporary exclusion zones—in the parts of the Black Sea as it chooses, most recently in Bulgaria’s exclusive economic zone (EEZ) from July 17 to the present (see EDM, August 3; Novinite.bg, August 6).
Those methods have, thus far, sufficed to intimidate Ukrainian and international commercial shipping from navigating in Ukrainian waters—and practically interdicted offshore oil and gas projects in Ukraine’s territorial waters and EEZ (the definition of which Russia reserves to itself). Bulgaria has also expressed unease regarding natural gas projects in its EEZ while Russian warships exercise there (Novinite.bg, August 3).
The blockade’s ultimate goal is not necessarily to prohibit Ukrainian seaborne exports and imports outright or totally. The goals are rather for Russia to dictate the “new” maritime boundaries according to Moscow’s own interpretation (“new realities”), unilaterally set the rules of navigation, enforce international compliance with them at least informally (tacitly) and retain the military capacity to interdict shipping outright, for any duration, as Russian leverage in international negotiations—whether during the war or in eventual “peace” negotiations.
At the moment, Russia demands economic and political concessions from Ukraine and its Western partners in return for relaxing the now-total blockade. The Kremlin has demonstrated that such relaxation is selective, partial, conditional, time-limited and revocable. It would in this case allow Ukrainian agricultural exports only, and even those only partially (see EDM, July 27).
Full control, rather than total blockade, is Russia’s ultimate goal. This has already been seen with the Kerch Strait crisis in 2018 and thereafter. Contrary to some perceptions at that time, Russia did not aim to cut Ukraine off from the Sea of Azov and the Black Sea outright, nor simply prohibit international shipping to and from Ukraine by “blocking” the Kerch Strait. Rather, Russia aimed to obtain de facto international acceptance of its seizure of (“sovereignty” over) Crimea and the Kerch Strait. It compelled international and Ukrainian shipping to follow—albeit tacitly—Russia’s definition of maritime boundaries, Russian-dictated rules of navigation and enter direct transactions with the Russian occupation authorities in the Port of Kerch. Meanwhile, Russia was also aiming to economically strangle Ukraine’s Azov Sea ports at Mariupol and Berdyansk—not in one fell swoop, but in slow motion, by manipulating and slowing down international and Ukrainian access in either direction through the Kerch Strait. Those tactics were proving successful by 2021–2022 when Russia decided to invade and occupy Ukraine’s Azov Sea coast.
Whether full control or total blockade, either situation presupposes unchallenged Russian hegemony in the Black Sea basin, absent a countervailing Western naval presence. This situation has developed following, first, the Western powers’ unforced decision in December 2021 to no longer send warships into the Black Sea in anticipation of Russia’s war; and second, Turkey’s decision in February 2022 to bar any warships of non-riparian countries from entering the Black Sea through the Bosporus Strait.
The documents of the North Atlantic Treaty Organization’s (NATO) recent Vilnius summit and the communiqué of the NATO-Ukraine Council’s meeting indicate (see EDM, July 19; July 31) that the allied powers do not intend, for the time being, to change their decision to keep their warships out of the Black Sea. There is no perceptible disagreement between the Western naval powers and Ankara over the closure of the Bosporus Strait. Their consensus is not only based legalistically on the Montreux Convention but is in equal measure political.
Ankara based its decision to close the Bosporus to non-riparian warships on a discretionary interpretation of the relevant provisions of the Montreux Convention. On February 27, 2022 (four days after the start of Russia’s “special military operation” in Ukraine), then–Turkish Foreign Minister Mevlut Cavusoglu announced that the Turkish government “has determined that this is a war.” Accordingly, Turkey invoked its authority under the Montreux Convention to close the Straits to non-riparian warships (and to Russian warships not homeported in the Black Sea) (CNN Turk, February 27, 2022).
Russia, however, had (for political reasons unrelated to the Black Sea) explicitly refrained from declaring a state of war, but only a special military operation as it remains officially to date. Turkey, in any case, is not a “belligerent” in this “war” in the sense of the Montreux Convention (Cil.nus.edu.sg, accessed August 6).
According to Article 19 of the convention, however, “in time of war, Turkey not being belligerent, warships shall enjoy complete freedom of transit and navigation through the Straits under the same conditions as those laid down in Articles 10 to 18” (these regulate the passage, types and tonnage of warships).
Under Article 20: “In time of war, Turkey being belligerent, the provisions of Articles 10 to 18 shall not be applicable; the passage of warships shall be left entirely to the discretion of the Turkish Government.”
And under Article 21: “Should Turkey consider herself to be threatened with imminent danger of war she shall have the right to apply the provisions of Article 20 of the present Convention” (i.e., full discretion).
Ankara has unilaterally characterized the situation as a “war.” However, its own non-belligerent status and its equally well-founded decision to not consider itself imminently threatened meant that Turkey lacked a clear authority to close the Bosporus Strait to allied warships. Its decision was (and remains) political and discretionary. The convention does give Turkey that discretion, but not for the case at hand (see above).
Thus, it is not the terms of the Montreux Convention per se, but Ankara’s own decision that has barred Western warships from entering the Black Sea since Russia re-invaded Ukraine. Risk-averse Western powers and the aggressor Russia seem—for opposite reasons—equally content with Turkey’s decision. Further debate seems, in any case, largely academic, as Turkey possesses de facto discretionary authority over the straits and is capable of enforcing it beyond challenge.
Ultimately, the eventual return of Western naval powers to the Black Sea will significantly depend on Turkey’s relations with its NATO allies and Russia, respectively.