premise: Kabila's rebels have captured more than half this country since they launched their offensive to topple Mobutu more than six months ago.
  The ailing Mobutu, 66, who is recuperating after prostate cancer surgery, has ruled over Zaire for 32 years.
  Earlier Wednesday, the president's son and spokesman Nzanga Mobutu said his father did not want to meet Kabila on board the South African vessel.
  Richardson said other African leaders would also take part in the encounter. He did not say who they would be, but went out of his way to praise South African President Nelson Mandela and his Gabonese counterpart Omar Bongo.
   What caused more than half the country to be captured by rebels?
hypothesis: their offensive to topple Mobutu