Foreign Service Officer
In the United States and several other countries, a Foreign Service Officer (FSO) is a professional career diplomats. While, in the broadest sense of the term, U.S. Foreign Service Officers (FSO) are civil servants, they have a distinct rank structure. Due to the need to represent the United States, may not have some of the administrative protections of a domestic government employee in a nonsensitive job.
Since 1975, the Director General of the Foreign Service, a position with Assistant Secretary rank, has also been the chief of human resources for the Department of State. The third-ranking position in the Department, Undersecretary of State for Political Affairs, is traditionally reserved for a Foreign Service Officer. Some FSOs have served as Deputy Secretary of State or as acting Secretary of State (e.g., Lawrence Eagleburger).
The highest U.S. Foreign Service rank is Career Ambassador, then Career Minister, then numbered grades from FSO-1 to the entry-level FSO-8. It is not always easy to establish seniority among military ranks, civil service ranks in the GS and GG series, and Senior Executive Service. Career Ambassador and Career Minister ranks definitely have the status of general officers or "supergrade" civil servants, although the mapping is blurry about the positioning of FSO-1. There are four general officer and five supergrade ranks in U.S. government practice.