U.S. Diplomatic Missions: Background and Issues on Chief of Mission (COM) Authority [March 10, 2014] [open pdf - 312KB]
"'Chief of Mission,' or COM, is the title conferred on the principal officer in charge of each U.S. diplomatic mission to a foreign country, foreign territory, or international organization. Usually the term refers to the U.S. ambassadors who lead U.S. embassies abroad, but the term also is used for ambassadors who head other official U.S. missions and to other diplomatic personnel who may step in when no ambassador is present. Appointed by the President, each COM serves as the President's personal representative, leading diplomatic efforts for a particular mission or in the country of assignment. U.S. ambassadors and others exercising COM authority are by law the cornerstone of U.S. foreign policy coordination in their respective countries. Their jobs are highly complex, demanding a broad knowledge of the U.S. foreign policy toolkit and the ability to oversee the activities and manage the representatives of many U.S. government entities, with some exceptions for those under military command. Congress plays an important role in setting standards for the exercise of COM authority and providing COMs with the resources--training, personnel, monetary--to promote its effective exercise. A number of recent developments have increased congressional attention to issues associated with the roles and responsibilities of COMs."
CRS Report for Congress, R43422