The Montreux Convention: Passage through the Straits and Turkish Authority

The Dardanelles, the Sea of Marmara, and the Bosporus form the waterway connecting the Mediterranean and Black Seas. The Lausanne Straits regime of 1923 placed navigation within an international arrangement while restricting military deployments in the Straits region. Turkey sought greater ability to defend the waterway; Black Sea states were concerned about the entry of foreign fleets; and commercial shipping required predictable passage rules.

On April 10, 1936, Turkey sent a note requesting revision to the relevant governments that had participated in the Lausanne negotiations. U.S. Ambassador to Turkey MacMurray's April 14 report recorded Foreign Minister Aras distinguishing Straits security from commercial navigation: Turkey sought to adjust military restrictions while maintaining freedom of navigation for merchant ships of all countries. This was a diplomatic request to convene a conference and revise existing arrangements.

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The conference met at Montreux, Switzerland, from June 22 to July 20, 1936. Turkey, the Soviet Union, Britain, France, and other interested states participated. The convention's signature document also lists representatives of Australia, Bulgaria, Greece, Japan, Romania, and Yugoslavia. Aras and Soviet Foreign Minister Litvinov were among the signatories. Italy did not attend.

After the conference, Aras explained to MacMurray that disputes had centered on which fleets could pass in wartime and whether such passage would compromise Turkish neutrality. The American diplomatic record preserves his position but cannot substitute for the full negotiating records of all participants. The final text restored Turkey's military and administrative powers while regulating their exercise according to vessel category, Black Sea coastal status, and conditions of war.

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Article 1 affirmed freedom of passage and navigation through the Straits. Article 2 specified the peacetime rule for merchant ships: passage by day or night regardless of flag or cargo. Ships passing through without entering a Straits port could be charged only the taxes and fees permitted by Annex I. Separate provisions governed sanitary inspections, so freedom of navigation did not mean the complete absence of quarantine procedures or information requirements.

Pilotage and towage were normally optional. During a war in which Turkey remained nonbelligerent, merchant ships could in principle continue under these conditions. If Turkey entered the war, relevant merchant ships had to belong to nonenemy states, provide no assistance to the enemy, and navigate by day along prescribed routes. Separate articles governed commercial shipping and warships.

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In peacetime, light surface vessels, minor war vessels, and auxiliary vessels could pass subject to conditions. Special provisions applied to Black Sea states' large capital ships and to their submarines built or purchased outside the Black Sea or requiring repairs elsewhere. Submarines had to pass singly, surfaced, and by day. Naval passage rights were therefore not identical for every state and ship type.

The normal diplomatic notice period was eight days; for non-Black Sea states, Article 13 expressed the desirability of extending it to fifteen days. Foreign naval forces passing through simultaneously were generally limited to 15,000 tons and nine vessels, with specified exceptions. The aggregate tonnage of non-Black Sea states in the Black Sea was normally capped at 30,000 tons, potentially rising to 45,000 under stipulated conditions. Their warships could not remain in the Black Sea for more than twenty-one days on a single visit.

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Article 19 provided that, in a war in which Turkey was not a belligerent, warships of belligerent states were generally barred from passage. It nevertheless preserved exceptions for return to their bases and for arrangements involving the League of Nations and certain mutual-assistance treaties. This restriction therefore cannot be summarized as an absolute ban on every belligerent warship under all circumstances.

When Turkey itself was a belligerent, Article 20 left decisions on warship passage to the Turkish government. Article 21 addressed situations in which Turkey considered itself threatened by imminent war, while requiring notification of the contracting states and the League of Nations secretary-general and providing for the review procedures then in place. These arrangements embodied the security mechanisms of the 1936 system and were not identical to the treatment of merchant shipping under different wartime conditions.

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The protocol signed on July 20 took effect that day, permitting Turkey immediately to remilitarize the Straits region and providing for provisional application of the new regime from August 15. MacMurray's telegram of July 22 reported that Turkish troops had entered the demilitarized areas of the upper Bosporus and Dardanelles and the relevant islands the previous day. This contemporary telegram records actual troop movements on a date distinct from the convention's signature.

Article 26 required instruments of ratification to be deposited with the French government and a record to be drawn up once at least six, including Turkey's, had been deposited. This procedure was completed on November 9, when the convention formally entered into force. It was registered with the League of Nations on December 11. Article 24 transferred the former international commission's functions to Turkey, requiring it to compile and communicate information about warship movements and submit annual reports. Signature, provisional application, entry into force, and continuing administration thus formed successive, connected steps.

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