Hugo Chavez’s announcement that he has cancer will terminate his ascent towards dictatorship even if he survives. Dictators cannot appear to be mortal. They cannot name successors, unless the successor is a personal extension, such as a son.
Preparing the groundwork for a successor-son takes time and absolute power as the Kim dynasty in North Korea can attest. The more common approach is to name no successor and let the fight begin after your death.
Stalin wrote the game book on modern dictatorship. He removed immediately, and usually permanently, anyone even rumored as his successor. Stalin understood that dictator remains in power only as long as his subordinates do not coalesce into a coalition strong enough to unseat him.
(photo credit: Bernardo Londoy)