Egypt has operated under a "state of emergency" for all but five months since 1967, allowing the president to outlaw demonstrations, hold detainees indefinitely without trial, and issue law by decree. Generally, emergency law provides the government with the authority to control every level of political activity, including that within the confines of the formally defined political arena. The duration of the law is three years, but it is routinely renewed. The trend began when President Gamel Abdel Nasser succeeded in establishing a state of emergency in 1956, following the invasion of Egypt by Britain, France, and Israel, and continued until 1963 on the basis of the continuing threat of an offensive against Egypt. Nasser declared another state of emergency in June 1967 because of the Six-Day War, which lasted through the War of Attrition, the October War, and the later years of Anwar El-Sadat's presidency, which were characterized by significant political, economic, and social upheaval and discontent. In total, the state of emergency declared during the 1967 war lasted for 13 years. After Sadat's assassination on 6 October 1981, his Vice-President and successor, Hosni Mubarak, declared another state of emergency, which he kept in place for the entire duration of his three decades in office.