Henry Alfred Kissinger (; born Heinz Alfred Kissinger ; May 27, 1923) is an American diplomat and political scientist. He served as National Security Advisor and later concurrently as United States Secretary of State in the administrations of Presidents Richard Nixon and Gerald Ford. For his actions negotiating the ceasefire in Vietnam (though never realised), Kissinger received the 1973 Nobel Peace Prize under controversial circumstances, with two members of the committee resigning in protest. After his term, his advice has been sought by world leaders including subsequent U.S. presidents.