Nasserism ( at-Tayyār an-Nāṣṣarī) is a socialist Arab nationalist political ideology based on the thinking of Gamal Abdel Nasser, one of the two principal leaders of the Egyptian Revolution of 1952, and Egypt's second President. Spanning the domestic and international spheres, it combines elements of Arab socialism, republicanism, nationalism, anti-imperialism, Developing world solidarity, and international non-alignment. In the 1950s and 1960s, Nasserism was amongst the most potent political ideologies in the Arab world. This was especially true following the Suez Crisis of 1956 (known in Egypt as the Tripartite Aggression), the political outcome of which was seen as a validation of Nasserism, and a tremendous defeat for Western imperial powers. During the Cold War, its influence was also felt in other parts of Africa, and the developing world, particularly with regard to anti-imperialism, and non-alignment.
The scale of the Arab defeat in the Six-Day War of 1967 damaged the standing of Nasser, and the ideology associated with him. Though it survived Nasser's death in 1970, certain important tenets of Nasserism were revised or abandoned totally by his successor, Anwar Sadat, during what he termed the ' Corrective Revolution', and later his Infitah economic policies. Under the three decade rule of Sadat's successor, Hosni Mubarak, most of the remaining socialist infrastructure of Egypt was replaced by neo-liberal policies strongly at odds with Nasserist principles. In the international arena, Mubarak departed almost entirely from traditional Egyptian policy, becoming a steadfast ally of both the U.S. government, and Israel, the latter still viewed by most Egyptians with enmity and distrust, derived largely from the five wars that Egypt fought against Israel between 1948 and 1973.
During Nasser's lifetime, Nasserist groups were encouraged and often supported financially by Egypt, to the extent that many became seen as willing agents of the Egyptian government in its efforts to spread revolutionary nationalism in the Arab World. In the 1970s, as a younger generation of Arab revolutionaries came to the fore, Nasserism outside of Egypt metamorphosed into other Arab nationalist, and pan-Arabist movements, including component groups of the Lebanese National Movement during the Lebanese Civil War. The main Nasserite movements that continued to be active until today on the Lebanese scene are mainly represented by the organization in Sidon of populist Nasserist partisans (al-Tanzim al-Sha'bi al-Nassiri) that are led by Oussama Saad, and in Beirut as represented mainly by the Mourabitoun movement. Both groups have been mainly active since the early 1950s among Sunni Muslims, and they are currently associated politically with the ' March 8' coalitions in Lebanese politics.
Nasserism continues to have significant resonance throughout the Arab world to this day, and informs much of the public dialogue on politics in Egypt, and the wider region. Prominent Nasserist Hamdeen Sabahi competed in the first round of the 2012 Egyptian Presidential election, and only narrowly avoided securing a position in the run-off against eventual winner Mohamed Morsi.