THE United States has ordered its non-essential staff in Chad to leave the African country as rebel fighters approached the capital on Sunday after early election results showed President Idriss Deby on course to extend his three-decade rule. Deby, who seized power in 1990 at the head of an armed rebellion, is a staunch ally of France and the United States in the fight against Islamist militants in the arid Sahel region. "Due to their growing proximity to N'Djamena and the possibility for violence in the city, non-essential U.S. government employees have been ordered to leave Chad by commercial airline,"…