The term "diplomatic immunity" refers to a principle of international law that limits the degree to which foreign government and international organization officials and employees are subject to the authority of police officers and judges in their country of assignment. Does this mean that foreign officials can get away with anything in the countries where they're posted, as is often assumed? Not exactly.
This article will take a closer look at the actual legal standards governing diplomatic immunity, especially in the United States. The basis for this is the Vienna Convention on Diplomatic Relations, which the U.S. has adopted.
Strictly speaking, the principle of diplomatic immunity does not apply to all foreign government or international organization officials and employees. When it does apply, it applies differently to different categories and subcategories of such persons and their families, dependent on circumstances.
(Note: Diplomatic immunity is also to be distinguished from "sovereign immunity," which applies to the person and property of foreign governments themselves and is not discussed in the present article.)
Diplomatic agents—that is, high ranking embassy officials (ambassadors, for example) who serve the function of dealing directly with their host country's officials on behalf of their home country—enjoy the highest degree of immunity. The same applies to their family members.
The police cannot detain them, arrest them, or search or seize their houses and other property. Diplomats cannot be prosecuted or otherwise forced to appear in criminal court. Nor can they be sued in civil courts, except for their personal (non-official) involvement in certain commercial, real-estate, or inheritance-related matters, or for their separate professional activities.
So, for example: An ambassador who is sued for failing to pay her personal home mortgage premium might lose title to her house but cannot be forced to pay damages and may not be evicted.
A second category of embassy personnel, the administrative and technical staff (secretaries, for example) who directly support diplomatic activities, enjoy the same immunity from police actions and criminal courts, but a lesser degree of immunity from civil courts. They can be sued like anyone else, except for acts performed in connection with their official function. (No such exception applies to their family members.) Accordingly, an embassy secretary who fails to pay his personal home mortgage premium could not only lose his title but also be sued for damages; though he may not be evicted.
Yet other embassy employees (chauffeurs, for example), who only indirectly support diplomatic activities, enjoy the lowest degree of immunity. They have (either criminal or civil) immunity only for acts performed in connection with their embassy role. Their family members enjoy no immunity at all.
There are exceptions. In rare cases, both the second and third categories of embassy personnel above may enjoy as much immunity as diplomatic agents. But this happens only when the home country and the host country enter a special agreement (or treaty) for that purpose. Moreover, home country governments can waive diplomatic immunity.
Finally, no immunity applies to embassy employees (or the family members of such employees) who are nationals or permanent residents of the host country.
Consular personnel generally enjoy less immunity than embassy personnel.
Consular officers (career consuls and other foreign government officials responsible for issuing travel documents, promoting commerce or tourism, and similar functions) enjoy full immunity for acts performed in connection with their official function. However, they are otherwise fully subject to criminal prosecution, except that they may be detained only in felony cases. (No such exception applies to their family members, who enjoy no immunity at all.)
Their property can be searched by police officers. They can also be sued like private citizens—although they are prohibited (by international law) from engaging in commercial or professional activities outside their official functions.
Consulates' administrative and technical staff are not prohibited from engaging in commercial or professional activities outside their official functions. However, they enjoy immunity only for acts performed in connection with their official functions.
Other consular employees enjoy almost no immunity, except that they cannot be forced to appear as witnesses in U.S. courts for purposes of providing evidence about official consular affairs.
Here again, there are exceptions. Consular personnel may acquire almost as much immunity as diplomatic agents based on a special treaty between their home country and their host country.
No immunity applies to consular personnel who are nationals or permanent residents of the host country, except that honorary consuls enjoy immunity for acts performed in connection with their official functions.
Interestingly, international law is often less important than national laws when it comes to defining the immunity of representatives and personnel of international organizations such as the United Nations or the International Monetary Fund.
Under U.S. law, high-ranking international government representatives (members of national missions who are assigned to international organizations) usually enjoy as much immunity as diplomatic agents, while all other national mission staff enjoy immunity only for acts performed in connection with their official functions.
Similarly, most international organization personnel enjoy immunity only for acts performed in connection with their official function, while some (but not all) high-ranking officials may sometimes enjoy almost as much immunity as diplomatic agents. For example: The Secretary General of the United Nations enjoys full diplomatic immunity, but the Director of the International Monetary Fund (as we saw in the case of Dominique Strauss-Kahn in 2011) does not.
Diplomatic immunity does not mean that its beneficiaries can do whatever they want and get away with it. Police officers are allowed to disregard it whenever necessary to prevent a grave crime or an imminent danger to public safety.
In cases of traffic violation, even though diplomatic vehicles may not be impounded, police officers are still allowed to issue citations, and host governments may suspend driving privileges.
In addition, host countries can request that home countries waive a crime suspect's immunity. In the alternative, host countries may expel the suspect from their territory.
Finally, especially when the principle extends only to acts performed in connection with official functions, it is important to note that it is host country judges themselves who get to define the limits of immunity.