In the course of its first session, in 1949, the Commission selected diplomatic intercourse and immunities as one of the topics for codification without, however, including it in the list of topics to which it gave priority. At its fifth session, in 1953, the Commission was apprised of General Assembly resolution 685 (VII) of 5 December 1952 (E, F, S, R, C), by which the Assembly requested the Commission to undertake, as soon as it considered possible, the codification of diplomatic intercourse and immunities and to treat it as a priority topic.

Extracts from The Work of the International Law Commission, 6th ed., vol. 1

At its sixth session, in 1954, the Commission decided to initiate work on the subject and appointed A. E. F. Sandström as Special Rapporteur. The Commission considered this topic at its ninth and tenth sessions, in 1957 and 1958, respectively. In connection with its work on this topic, the Commission had before it the reports of the Special Rapporteur, [1]  information provided by Governments [2]  as well as a document prepared by the Secretariat. [3]

At its ninth session, in 1957, on the basis of the report by the Special Rapporteur, [4]  the Commission, adopted on first reading a set of draft articles with commentaries. The draft was circulated to Governments for comment and was also included in the report submitted by the Commission to the Assembly’s twelfth session, in 1957. At its tenth session, in 1958, the Commission adopted the final draft on diplomatic intercourse and immunities consisting of forty-five draft articles, with commentaries. [5]  In submitting this final draft to the General Assembly, the Commission recommended that the General Assembly recommend the draft to Member States with a view to the conclusion of a convention. [6]

The Commission pointed out that the draft dealt only with permanent diplomatic missions. The Commission had, however, asked the Special Rapporteur to study and, at one of its future sessions, make a report on other forms of diplomatic relations, that is, so-called “ad hoc diplomacy”, covering itinerant envoys, diplomatic conferences and special missions sent to a State for limited purposes. The Commission’s report also referred to relations between States and international organizations and the privileges and immunities of such organizations. In this respect, the Commission simply remarked that these matters were, as regards most of these organizations, governed by special conventions. [7]

During the Sixth Committee’s debate, in 1958, on the report of the International Law Commission, some representatives expressed doubts as to whether it was desirable to codify by convention the rules regarding diplomatic privileges and immunities. It was argued that the matter was adequately governed by custom and usage and that regulation by convention would introduce an element of rigidity. An attempt to lay down strict treaty rules on the subject, it was also contended, might even result in the reduction of the privileges and immunities at present enjoyed in practice by members of diplomatic missions. A restatement of current usage would for these reasons be preferable to regulation by convention. [8]

The majority of members, however, favoured codifying the subject by convention, but were divided into two groups regarding the procedure to be followed. One group proposed that the preparation of a convention should be entrusted to the Sixth Committee; the other group preferred the convening of a conference of plenipotentiaries for that purpose. The General Assembly, by resolution 1288 (XIII) of 5 December 1958 (E, F, S, R, C, A), deferred action until its fourteenth session, in 1959, at which it finally endorsed the recommendation of the Commission and decided, in resolution 1450 (XIV) of 7 December 1959 (E, F, S, R, C, A), to convene a conference of plenipotentiaries not later than the spring of 1961. The Commission’s final report on diplomatic intercourse and immunities, containing the draft articles, was referred to the conference by the Assembly. A year later, by resolution 1504 (XV) of 12 December 1960 (E, F, S, R, C, A), the Assembly also referred to the conference three draft articles on special missions approved by the Commission at its twelfth session, in 1960, so that they could be considered together with the draft articles on permanent diplomatic relations.

The United Nations Conference on Diplomatic Intercourse and Immunities met in Vienna from 2 March to 14 April 1961. [9]  It was attended by delegates from eighty-one countries, seventy-five of which were Members of the United Nations and six of related agencies or parties to the Statute of the International Court of Justice. The Conference set up a Committee of the Whole, to which it referred the substantive items on its agenda, namely, consideration of the question of diplomatic intercourse and immunities, consideration of draft articles on special missions, and the adoption of instruments regarding the matters considered and of the Final Act of the Conference. The draft articles on special missions were referred by the Committee of the Whole to a Subcommittee on Special Missions.

The Conference adopted a convention entitled the “Vienna Convention on Diplomatic Relations”, [10]  consisting of fifty-three articles and covering most major aspects of permanent diplomatic relations between States. It also adopted an Optional Protocol concerning Acquisition of Nationality [11]  and an Optional Protocol concerning the Compulsory Settlement of Disputes. [12]   By a resolution adopted by the Conference, the subject of special missions was referred back to the General Assembly with the recommendation that the Assembly entrust to the International Law Commission the task of further study of the topic.

The Final Act of the Conference was signed on 18 April 1961. The Convention and Optional Protocols remained open for signature until 31 October 1961 at the Federal Ministry for Foreign Affairs of Austria and subsequently, until 31 March 1962, at United Nations Headquarters. They remain open for accession at any time by all Members of the United Nations or of any of the specialized agencies or Parties to the Statute of the International Court of Justice, and by any other State invited by the General Assembly to become a party. The Convention and the two Optional Protocols entered into force on 24 April 1964.

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