The current system of diplomatic ranks was established by the Vienna Convention on Diplomatic Relations (1961). There are three ranks, two of which remain in use:
- Ambassador. An Ambassador is a head of mission who is accredited to the receiving country's head of state. They head a diplomatic mission known as an embassy, which is usually headquartered in a chancery in the receiving state's capital.
- A papal nuncio is considered to have Ambassadorial rank, and presides over a nunciature.
- Commonwealth countries send a High Commissioner who presides over a High Commission and has the same diplomatic rank as an Ambassador.
- Minister. A Minister was a head of mission who was accredited to the receiving country's head of state. A Minister headed a legation rather than an embassy. After World War II, the embassy became the standard form of diplomatic mission, and the rank of Minister is now obsolete. Many countries use the title minister-counsellor to refer to the deputy head of a mission, but does not hold the rank of Minister.
- An envoy or an internuncio is also considered to have the rank of Minister.
- Chargé d'affaires:
- A chargé d'affaires en pied is a permanent head of mission who is accredited by their country's Foreign Minister to the receiving nation's Foreign Minister, in cases where the two governments have not reached an agreement to exchange ambassadors.
- A chargé d'affaires ad interim is a diplomat who temporarily heads a diplomatic mission in the absence of an ambassador.
The body of diplomats accredited to a country form the diplomatic corps. Ambassadors have precedence over chargés, and precedence within each rank is determined by the date on which diplomatic credentials were presented. The longest-serving ambassador is the Dean of the Diplomatic Corps, who speaks for the entire diplomatic corps on matters of diplomatic privilege and protocol. In many Catholic countries, the papal nuncio is always considered the Dean of the Diplomatic Corps.
Historical ranks, 1815–1961
The ranks established by the Vienna Convention (1961) modify a more elaborate system of ranks that was established by the Congress of Vienna (1815):
- Ambassadors, Legates, and Nuncios were personal representatives of their sovereign.
- Envoys and Ministers represented their government, and were accredited to the receiving sovereign.
- Ministers resident formed an intermediate class, between ministers and chargés. This rank was created by the Congress of Aix-la-Chapelle (1818)
- Chargés d'affaires were accredited by their Foreign Minister to the receiving Foreign Minister.
The rank of Envoy was short for "Envoy Extraordinary and Minister Plenipotentiary", and was more commonly known as Minister. For example, the Envoy Extraordinary and Minister Plenipotentiary of the United States to the French Empire was known as the "United States Minister to France" and addressed as "Monsieur le Ministre".
An Ambassador was regarded as the personal representative of his sovereign as well as his government. Only major monarchies would exchange Ambassadors with each other, while smaller monarchies and republics only sent Ministers. Because of diplomatic reciprocity, Great Powers would only send a Minister to a smaller monarchy or a republic. For example, in the waning years of the Second French Empire, the United Kingdom sent an Ambassador to Paris, while Sweden-Norway and the United States sent Ministers.
The rule that only monarchies could send Ambassadors was more honored in the breach than the observance. This had been true even before the Congress of Vienna, as England continued to appoint ambassadors after becoming a republic in 1649. Countries that overthrew their monarchs proved to be unwilling to accept the lower rank accorded to a republic. After the Franco-Prussian War, the French Third Republic continued to send and receive ambassadors. The rule became increasingly untenable as the United States grew into a Great Power. The United States followed the French precedent in 1893 and began to exchange ambassadors with other Great Powers.
Historically, the order of precedence had been a matter of great dispute. European powers agreed that the papal nuncio and Imperial Ambassador would have precedence, but could not agree on the relative precedence of the kingdoms and smaller countries. In 1768, the French and Russian ambassadors to Great Britain even fought a duel over who had the right to sit next to the Imperial Ambassador at a court ball. After several diplomatic incidents between their ambassadors, France and Spain agreed in 1761 to let the date of arrival determine their precedence. In 1760, Portugal attempted to apply seniority to all ambassadors, but the rule was rejected by the other European courts.
The Congress of Vienna finally put an end to these disputes over precedence. After an initial attempt to divide countries into three ranks faltered on the question of which country should be in each rank, the Congress instead decided to divide diplomats into three ranks. A fourth rank was added by the Congress of Aix-la-Chapelle (1818). Each diplomatic rank had precedence over the lower ranks, and precedence within each rank was determined by the date that their credentials were presented. The papal nuncio could be given a different precedence than the other ambassadors. The Holy Roman Empire had ceased to exist in 1806, so the Austrian ambassador would accumulate seniority along with the other ambassadors.
The distinction between managers and officers is not necessarily as apparent. Senior officers (such as first and second secretaries) often manage junior diplomats and locally hired staff.
In modern diplomatic practice, there are a number of diplomatic ranks below Ambassador. Since most missions are now headed by an ambassador, these ranks now rarely indicate a mission's (or its host nation's) relative importance, but rather reflect the diplomat's individual seniority within their own nation's diplomatic career path and in the diplomatic corps in the host nation:
- Ambassador (High Commissioner in Commonwealth missions to other Commonwealth countries); ambassador at large
- First Secretary
- Second Secretary
- Third Secretary
- Assistant Attaché
The term attaché is used for any diplomatic agent who does not fit in the standard diplomatic ranks, often because they are not (or were not traditionally) members of the sending country's diplomatic service or foreign ministry, and were therefore only "attached" to the diplomatic mission. The most frequent use is for military attachés, but the diplomatic title may be used for any specific individual or position as required, generally related to a specific or technical field. Since administrative and technical staff benefit from only limited diplomatic immunity, some countries may routinely appoint support staff as attachés. Attaché does not, therefore, denote any rank or position (except in Soviet and post-Soviet diplomatic services, where attaché is the lowest diplomatic rank of a career diplomat). Note that many traditional functionary roles, such as press attaché or cultural attaché, are not formal titles in diplomatic practice, although they may be used as a matter of custom.
Furthermore, outside this traditional pattern of bilateral diplomacy, as a rule on a permanent residency basis (though sometimes doubling elsewhere), certain ranks and positions were created specifically for multilateral diplomacy:
- An ambassador-at-large is equivalent to an ambassador and assigned specific tasks or region in which he is assigned various assignments aimed at multi track diplomacy.
- A permanent representative is the equivalent of an ambassador, normally of that rank, but accredited to an international body (mainly by member—and possibly observer states), not to a head of state.
- A resident representative (or sometimes simply representative) is also a member of the diplomatic corps, but is below the rank of ambassador. A representative is accredited by an international organization (generally a United Nations agency, or a Bretton Woods institution) to a country's government. The resident representative typically heads the country office of that international organization within that country.
- A special ambassador or honorary ambassador is a government's specialist diplomat in a particular field, not posted in residence, but often traveling around the globe.
- The U.S. Trade Representative (USTR) is an ambassador of Cabinet rank, in charge of U.S. delegations in multilateral trade negotiations (since 1962). The USTR's Special Agricultural Negotiator also typically holds an ambassadorial appointment.
Special envoys have been created ad hoc by individual countries, treaties and international organizations including the United Nations. A few examples are provided below:
- Belgium: In 2005, former cabinet member Pierre Chevalier served as Special Envoy of the Organization for Security and Co-operation in Europe presidency to mediate in the Gazprom natural gas-pipeline crisis involving Russia, Ukraine, and the European Union. In addition, Princess Astrid of Belgium has served as Special Envoy of the Anti-Personnel Mine Ban Convention or Ottawa Treaty, to promote the formal prohibition of landmines and the rights of the survivors of said weapons.
- India: During the 2006 democracy movement in Nepal, India sent on April 18 Karan Singh, who is related to royalty in both predominantly Hindu countries, as Special Envoy to neighbouring Nepal where increasingly violent opposition started its successful challenge of the king's autocratic rule. Another instance was during the 2009 Copenhagen climate change summit, India appointed senior diplomat Shyam Saran as a special envoy to coordinate the negotiating position of the BASIC countries.
- United Kingdom: appointed special envoys from time to time.
- European Union: appointed various special representatives (some regional, some thematic); e.g., in 2005—as a response to events in Kyrgyzstan and Uzbekistan—the Council of the EU appointed Jan Kubis as its "Special Representative for Central Asia".
- Pakistan: Prime Minister Nawaz Sharif Appointed Ambassador Javed Malik as Pakistan's Special Envoy for Trade & Investment based in the GCC Gulf region with a diplomatic rank of an Ambassador
- United States: appointed numerous special envoys including a Special Envoy for Northern Ireland with the diplomatic rank of ambassador to help with the Northern Ireland peace process. Special Envoys have also been appointed for Sudan, Syria,
Middle East Peace, Eurasian Energy, Climate Change, and Human Rights in North Korea. Other posts include Special Representative, Special Advisor, and Special Coordinator.
- The Secretary-General of the United Nations personally mandates special envoys for a particular field, including:
- The Director-General of UNESCO appoints special envoys who can use their talents and renown to further the organization's ideals and action. Envoys include:
- A sui generis case is the High Representative for Bosnia and Herzegovina.
- The Australian Department of Foreign Affairs and Trade maintains a variety of special interest ambassador and envoy positions including the Ambassador for Counter-Terrorism and the Ambassador for the Environment.