"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. The concept of immunity began with ancient tribes. In order to exchange information, messengers were allowed to travel from tribe to tribe without fear of harm. They were protected even when they brought bad news. Today, immunity protects the channels of diplomatic communication by exempting diplomats from local jurisdiction so that they can perform their duties with freedom, independence, and security. Diplomatic immunity is not meant to benefit individuals personally; it is meant to ensure that foreign officials can do their jobs. Under the concept of reciprocity, diplomats assigned to any country in the world benefit equally from diplomatic immunity.
The Vienna Convention on Diplomatic Relations of 1961 and the Vienna Convention on Consular Relations of 1963 codified most modern diplomatic and consular practices, including diplomatic immunity. More than 160 nations are parties to these treaties. The conventions provide immunity to persons according to their rank in a diplomatic mission or consular post and according to the need for immunity in performing their duties. For example, diplomatic agents and members of their immediate families are immune from all criminal prosecution and most civil law suits. Administrative and technical staff members of embassies have a lower level of immunity. Consular officers serving in consulates throughout the country have an even lower level of immunity. Members of an embassy's service staff and consular employees are immune only for acts performed as part of their official duties
It is true that diplomats are exempt from the criminal, civil and administrative jurisdiction of the host country. However, this exemption may be waived by their home country. Moreover, the immunity of a diplomat from the jurisdiction of the host country does not exempt him/her from the jurisdiction of his/her home country.
It is also within the discretion of the host country to declare any member of the diplomatic staff of a mission persona non grata (or unwanted person). This may be done at any time and there is no obligation to explain such a decision. In these situations, the home country, as a rule, would recall the person or terminate his/her function with the mission.
The Vienna Convention provides for specific measures that can be taken by both the home and host countries in cases of misuse or abuse of diplomatic privileges and immunities. On the whole, diplomatic privileges and immunities have served as efficient tools facilitating relations between States. No UN Member State has so far proposed rescinding the Convention or re-writing its provisions.
Diplomatic privileges and immunities guarantee that diplomatic agents or members of their immediate family:
May not be arrested or detained
May not have their residences entered and searched
May not be subpoenaed as witnesses
May not be prosecuted"