

HUN SEN: 25 years, 2 months. Cambodia’s prime minister was thrust into power in January 1985, making the 33-year-old the youngest prime minister in the world. The former Khmer Rouge cadre’s journey from communist leader to elected head of government spans 25 years of civil war and a massive UN-administered transition to democracy. His government is one of the world's most corrupt and is widely accused of pillaging the country's natural resources.
DENIS SASSOU NGUESSO: 25 years, 11 months. Mr. Nguesso seized the presidency in the Congo Republic in a 1979 coup but then lost the country’s first elections in 1992. He regained the presidency in 1997 and was re-elected in 2004.
PAUL BIYA: 27 years, 4 months. Mr. Biya assumed Cameroon’s presidency in November 1982. David Wallechinsky’s book “Tyrants, the World's 20 Worst Living Dictators,” says of him: “Every few years, Biya stages an election to justify his continuing reign, but these elections have no credibility. In fact, Biya is credited with a creative innovation in the world of phony elections. In 2004, annoyed by the criticisms of international vote-monitoring groups, he paid for his own set of international observers, six ex-U.S. congressmen, who certified his election as free and fair.”
HOSNI MUBARAK: 28 years, 5 months. Referred to as Egypt’s “last pharaoh,” Mr. Mubarak became president of the Arab world’s most populous country in October 1981. Mr. Mubarak was not clear if he would stay in power until the September presidential election.
ROBERT MUGABE: 30 years. Mr. Mugabe became Zimbabwe’s prime minister in 1980 following independence from Britain. The former Marxist guerrilla became president in 1987 and has held fast to that position despite a deep financial crisis pushing inflation above 164,900.3 percent. He formed a unity government in 2009 with opposition Prime Minister Morgan Tsvangirai.
JOSE EDUARDO DOS SANTOS: 30 years, 6 months. Mr. dos Santos assumed Angola’s presidency in September 1979. Since then, the nation rich in oil and diamonds has remained mostly poor, and in January 2010 the parliament approved a new Constitution whereby dos Santos must no longer be directly voted into power by the populace.
TEODORO OBIANG NGUEMA MBASOGO: 30 years, 7 months. Mr. Obiang assumed power in Equatorial Guinea when he kicked his uncle Macias out of the palace in August 1979. He was elected in 1996 and 2002 during the country’s first two multi-party elections, both widely deemed fraudulent. The 2008 article “Who's Africa’s Worst Dictator?” that appeared in Slate wrote of Obiang: “His is the Switzerland of dictatorships—so effective at enforcing obedience that the spectacle of unrest is invisible.”
ALI ABDULLAH SALEH: 31 years, 8 months. Mr. Saleh ruled North Yemen for almost 12 years, starting in July 1978, before becoming president of the newly formed Republic of Yemen. Despite announcing in 2002 that he would not seek another term, Saleh changed his mind and was reelected. [Editor's note: the original version misidentified Yemen's leader.]
MUAMMAR QADDAFI: 40 years, 6 months. Mr. Qaddafi seized power in a bloodless military coup in September 1969. Thanks to sitting on top of Africa's largest proven oil reserves, he is used to throwing his weight around internationally, and usually gets what he wants. He had himself introduced at the 2009 UN General Assembly General Assembly Hall as the “leader of the revolution, the president of the African Union, the king of kings of Africa.”
THE CASTRO BROTHERS: 51 years, 2 months. It’s hazy as to when Fidel stopped ruling Cuba and Raúl began, though in February 2008 the long-serving leader said he would not accept another term as president and his younger brother was voted into the seat. Fidel’s army rolled victoriously into Havana in January 1959. The Castro’s have outlasted nine US presidents despite CIA plots, a US-backed exile invasion at the Bay of Pigs, and decades of economic sanctions.