Twenty-second Amendment to the United States Constitution
Since coming into force in 1951, the amendment has applied to six presidents who have been elected twice: Dwight D. Eisenhower, Richard Nixon, Ronald Reagan, Bill Clinton, George W. Bush, and Barack Obama. It has also applied to two who entered office intra-term due to their predecessor's death or resignation: Lyndon B. Johnson and Gerald Ford. Johnson became president in November 1963, following the assassination of John F. Kennedy, served out the final of Kennedy's term, and was elected to a full four-year term in 1964. Four years later, he briefly ran for a second full term, but withdrew from the race during the party primaries. Had Johnson served a second full term – through January 20, 1973 – the total length of his presidency would have been ; as it happened, Johnson died two days after this date. Gerald Ford, who became president in August 1974 following the resignation of Richard Nixon, served the final of Nixon's term, and attempted to win a full four-year term in 1976, but was defeated by Jimmy Carter. Johnson was eligible to be elected to two full terms in his own right, as he had served less than two years of Kennedy's unexpired term, whereas Ford was eligible to be elected to only one full term, as he had served more than two years of Nixon's unexpired term.
Presidency
For former presidents who had entered office before January 1, 1997 are entitled to lifetime protection carried out by The Secret Service. Protection of the president's spouse is also granted until death or in the case of remarriage. In 1984 the ability to decline Secret Service protection was enacted by legislation enacted. The costs of protecting former presidents and dependents are not publicized by the Secret Service due to security reasoning. Former presidents who entered office after January 1, 1997 are limited to ten years of protection for themselves and their spouses. A spouse’s protection ends upon divorce, remarriage, or the former president’s death.
According to the 25th Amendment to the United States Constitution, the death of a president still active in office is automatically entitles his or hers spouse to one year of protective services. However, authorization of protection can be issued by the Secretary of Homeland Security. Children of former presidents, up to the age of 16, are guaranteed the same services as long as the time period does not surpass 10 years. In addition to direct protection, the Secret Service was entitled to investigate any potential threats against the former presidents and their dependents by the Presidential Threat Protection Act passed in 2000. The act passed by the 106th Congress can be deciphered as so: To amend section 879 of title 18, United States Code, to provide clearer coverage over threats against former presidents and members of their families, and for other purposes.