secretary of state
The head of the United States Department of State, whom is often seen as the chief foreign advisor and diplomat (besides the President) in the United States. He or she must be appointed by the President of the United States and confirmed by the United States Congress before he or she can take the oath of office. He or she serves at the cabinet level for as long as the appointing President is in power.
The Secretary of State is fourth in line in the Presidential Order of Succession.