The Cominform rift

When the treaty was adopted, Yugoslavia had already been expelled from the Cominform, the political grouping of all the Communist parties in the Soviet bloc. Yet it still voted down the line with the other non-Western countries, nearly 200 miles of the Danube flowing through its territory and the only navigable channel through the Iron Gate being on the Yugoslav side of the Romanian border. Nevertheless, when the new commission organized its staff, the Yugoslavs were offered only four minor posts out of sixty permanent appointments. The Josip Broz Tito government refused them all.^[6]

The commission also fixed freight rates that allegedly discriminated against Yugoslavia, Belgrade officials said. Faced with this situation,

the Yugoslav delegate to the commission has been most uncooperative. He has been a minority of one on every major question that has come up for discussion. He opposed, for example, the creation of a special administration fluviale [river administration] run by a joint Czechoslovak–Hungarian Commission to control the difficult Gabcikovo–Gönyű sector… The Yugoslavs lost by six votes to one. But they have at least got their own back by refusing to pay their share of the commission's expenses.^[7]

Another report, however, stated that it was the commission itself that "had made a determined effort to avoid accepting Yugoslavia's share in the expenses," which were even larger than the Yugoslav contribution to the United Nations.^[8]

These grievances were compounded by the vast powers wielded by the Soviet Union. At the session of November 11, 1949, a Soviet proposal was adopted vesting complete powers of appointment, organization, leadership, and negotiation in the secretary, who was the Russian representative. By 1950,

the Soviet government [had] assumed complete control over the Commission's administrative machinery and reduced the other governments to nominal status… Yugoslav representatives [had] been excluded from every important committee.^[9]

At the May 1951 meeting, the Yugoslavs walked out, forcing adjournment. They were protesting the "railroading" of shipping regulations they thought would hurt their economy: a rule forbidding inspection of foreign ships by the nations through which they were passing. The Yugoslavs charged sabotage and infiltration by Soviet agents aboard the ships. In August, Yugoslavia told the USSR in a note that the commission's rules were "contrary in letter and spirit" to the 1948 convention, giving the Soviets control of the waterway in violation of national sovereignty.

At the commission's fifth session, in June 1952, Yugoslavia proposed the establishment of an executive committee to be composed of one representative from each country; it would control business between formal sessions of the commission. The Soviet bloc voted to study the plan "sometime between the sixth and seventh sessions."^[10] Next, Yugoslavia proposed that the top posts should be rotated among the six members every three years, but the commission rejected that suggestion in June 1953. Rumors sprang up that Yugoslavia would resign from the commission because of this treatment.^[11]

Slowly, though, the picture changed with a thaw in Yugoslav–Soviet relations. On December 15, 1953, Dragoje Djuric, a Yugoslav diplomat, was elected to the secretary's post, a Hungarian was named president and a Bulgarian vice president.^[12] A Belgrade spokesman said in glee that the sessions were unusually harmonious because the Iron Curtain countries were agreeing to "all proposals put on the agenda by the Yugoslavs," one of them being a Yugoslav–Hungarian proposal to move the commission's headquarters in 1954 from Galatz to Budapest.^[13]

Later, though, the Soviet bloc intimated the downgrading of the Danube Commission. A Vienna dispatch reported that the Council for Mutual Economic Assistance (Comecon), the Eastern European equivalent of the Marshall Plan, had created a new, permanent Danube committee of its own, its purpose to draft measures for using Danube water for power, irrigation, and navigation. It ordered at a Moscow meeting that plans be made to raise the level of the river by dams so seagoing ships could move farther upstream.^[14]

East–west detente

The Danube Commission was seen as a bridge between East and West. Czechoslovak researcher Juraj Cuth wrote in 1960 that the Danube Commission, "has become an important center of close cooperation of all the riparian states… It has turned into a forum of cooperation between representatives of socialist and capitalist states."^[15]

Gabčíkovo–Nagymaros Dams

In 1977 the Gabčíkovo–Nagymaros Dams project was initiated by the Budapest Treaty between the Czechoslovak Socialist Republic and the Hungarian People's Republic. The project aimed at preventing catastrophic floods in the Danube river, producing clean electricity by damming the river, creating reservoirs, locks for navigation and a hydro electric power plant. Slovakia took over half of the project on 1 December 1993 when the country split however Hungary had abandoned the project in 1989 and tried to get out of the agreement.^[16] The International Court of Justice was called upon to judge the case and found Hungary had breached their legal obligations in almost all points, ordering that the project be completed. It was 2017 before the legal dispute was closed.

During Russo-Ukrainian War

After the beginning of the full-scale Russian invasion of Ukraine during the 12th extraordinary session on 17 March 2022 the Representatives of the member states adopted the Decision concerning the military aggression by the Russian Federation against Ukraine, violating the basic principles of the Belgrade Convention (doc. DC/SES-XII Extr./3). According to this decision the full powers of all representatives of the Russian Federation have been declined; they have been excluded from the participation in all meetings at the Danube Commission and its working bodies until the restoration of peace, sovereignty and territorial integrity of Ukraine within its internationally recognized borders.^[18]

During its 100th session on 14 December 2023 the Danube Commission decided that Russian membership is incompatible given its missile and drone strikes on the Lower Danube. Russia must leave by February 29th, 2024, or the Commission’s members will no longer recognize their commitments to Russia under the founding Belgrade Convention.^[19]