Diplomatic immunity is a principle of international law by which certain foreign government officials are not subject to the jurisdiction of local courts and other authorities for both their official and, to a large extent, their personal activities. The principle of diplomatic immunity is one of the oldest elements of foreign relations.

Ancient Greek and Roman governments, for example, accorded special status to envoys, and the basic concept has evolved and endured until the present. As a matter of international law, diplomatic immunity was primarily based on custom and international practice until quite recently. In the period since World War II, a number of international conventions (most noteworthy, the Vienna Convention on Diplomatic Relations and the Vienna Convention on Consular Relations) have been concluded. These conventions have formalized the customary rules and made their application more uniform.

The special privileges and immunities accorded foreign diplomatic and consular representatives assigned to the United States and other countries reflect rules developed among the nations of the world regarding the manner in which civilized international relations must be conducted. The underlying concept is that foreign representatives can carry out their duties effectively only if they are accorded a certain degree of insulation from the application of standard law enforcement practices of the host country. The United States benefits greatly from the concept as it protects U.S. diplomats assigned to countries with judicial systems far different from our own.

Although each host country may have some slightly different procedure by which they extend diplomatic courtesy, an International Diplomat - as a general rule - may expect so many benefits and privileges from the Worldwide Diplomatic Community that they are difficult to list.

A few of them are:

• Red Carpet Treatment by international governments.
• No Tax Liability on income from outside the host country.
• You may display "CC" (Corps Consulaire) plates on your car so that your status is known to the forces of control who may not detain you in any way
• Confidential movement and activity - Internationally.
• When travelling, you may use the diplomatic channel at airports and will not be subject to time delaying and annoying customs checks
• Prestige beyond imagination - both professionally and socially.
• Accessibility to Offshore Tax Havens for business and privacy.
• Unlimited entry and exit privilege from host country
  for worldwide professional or personal travel
• You will meet top–ranking government officials and heads of state
• Diplomatic Immunity - under International Law, the office and residence of diplomats are extended sovereign status, as such they are off limits to all governments and their agents - even in the host country.
• You will boost your business success as well as your social status and prestige
• Free Diplomatic vehicle license plates (CC or CD).
• No travel or airport departure tax.
• Free upgrades on airlines, car rental, hotels and cruises.
• Priority booking on reservations and more.

The allure of joining an unique clique of special people, who can do things that ordinary people cannot, is attractive.  One can travel through diplomatic channels, often without visas, one can instantly arrange a table at the busiest restaurants, and one can obtain special service and discounts in a wide range of exclusive stories. 

Volvo and some other brands are giving super big discounts for diplomatic persons.  The donations involved with diplomatic appointments are sometimes smaller than the yearly-long discounts you can get.  With your diplomatic passport you can of course set up a nice trade in cars with big profits.

According the the Vienna Convention, there are several main purposes of establishing a diplomatic mission:

(a) representing the sending State in the receiving State;
(b) protecting in the receiving State the interests of the sending State and of its nationals, within the limits permitted by international law;
(c) negotiating with the Government of the receiving State;
(d) ascertaining by all lawful means conditions and developments in the receiving State, and reporting thereon to the Government of the sending State;
(e) promoting friendly relations between the sending State and the receiving State, and developing their economic, cultural and scientific relations.

Each diplomatic mission usually consists of several departments. According to the Convention they are:

(a) the "head of the mission" is the person charged by the sending State with the duty of acting in that capacity;
(b) the "members of the mission" are the head of the mission and the members of the staff of the mission;
(c) the "members of the staff of the mission" are the members of the diplomatic staff, of the administrative and technical staff and of the service staff of the mission;
(d) the "members of the diplomatic staff" are the members of the staff of the mission having diplomatic rank; 
(e) a "diplomatic agent" is the head of the mission or a member of the diplomatic staff of the mission;
(f) the "members of the administrative and technical staff" are the members of the staff of the mission employed in the administrative and technical service of the mission;
(g) the "members of the service staff" are the members of the staff of the mission in the domestic service of the mission;
(h) a "private servant" is a person who is in the domestic service of a member of the mission and who is not an employee of the sending State;
(i) the "premises of the mission" are the buildings or parts of buildings and the land ancillary thereto, irrespective of ownership, used for the purposes of the mission including the residence of the head of the mission.

Generally, members of the diplomatic staff of the mission should in principle be of the nationality of the sending State. However to the consent of the recieving State, members can be appointed among the persons having the nationality of that State. That is why most positions for non-residents usually are supplied with a citizenship of the sending State.

For more information on diplomatic immunity please examine Vienna Convention on Diplomatic Relations and Optional Protocols (done at Vienna, on 18 April 1961) and Vienna Convention on Consular Relations and Optional Protocols (done at Vienna, on 24 April 1963).