Precedence
Precedence, in social matters, priority of place. On state occasions of a ceremonial or formal nature, precedence determines the order of appearance and seating of dignitaries, and the order of their departure.
In Great Britain, the rules of precedence have been determined by Parliament partly on the basis of royal or noble rank and partly on the holding of church and state offices. The sovereign has precedence over all other persons.
In the United States, precedence has been determined by custom rather than law. It depends in general on the importance of public positions. The office of protocol of the U.S. Department of State follows this order of precedence:
President; foreign head of state; foreign head of government; Vice President; chief justice of the United States; former Presidents; foreign ambassadors; speaker of the House of Representatives; secretary of state; U.S. representative to the United Nations; foreign ministers plenipotentiary; associate justices of the Supreme Court; other cabinet members. Wives and husbands of officials receive the same social rank as their spouses.