Speaker of the United States House of Representatives by the President "pro tempore" of the Senate and by the heads of federal executive departments. To date, the implementation of the Presidential Succession Act has never been necessary and no Speaker has ever acted as President. Implementation of the law almost became necessary in 1973 after the resignation of Vice President Spiro Agnew. At the time, many believed that President Richard Nixon would resign because of the Watergate scandal, allowing Speaker Carl Albert to succeed to the Presidency. However, before he resigned, Nixon appointed Gerald Ford as Vice President in accordance with the Twenty-fifth Amendment. Nevertheless, the United States
Vice President of the United States practice, the presidential nominee has considerable influence on the decision, and in the 20th century it became customary for that person to select a preferred running mate, who is then nominated and accepted by the convention. In recent years, with the presidential nomination usually being a foregone conclusion as the result of the primary process, the selection of a vice presidential candidate is often announced prior to the actual balloting for the presidential candidate, and sometimes before the beginning of the convention itself. The first presidential aspirant to announce his selection for vice president before the beginning of the convention