Sassou-Nguesso, Denis (dĕˈnē säsˈō-əngāˈsō) [key], 1943?–, Congolese army officer and president (1979–92, 1997–) of Congo (Brazzaville). He served (1977–79) as the minister of national defense. As president he won approval for a new Marxist constitution and signed (1981) a friendship treaty with the USSR, while maintaining the Congo's strong economic ties with France. The increasing economic impoverishment of the Congo, however, led to a national political conference (1991) that stripped him of many powers. In 1992 he ran for reelection in a democratic contest and came in third. Prolonged fighting and unrest following disputed parliamentary elections in 1993 ultimately led to a victory by Sassou-Nguesso's forces in 1997, and he again became president. He was elected president in 2002 and reelected in 2009; both votes were marred by irregularities.