He doesn't want to give up power to anybody else, and is thus slowly sliding towards authoritarian rule to keep his position. Each election he has to go a bit further to hold on.
Like many populists, he seems to have started out with fairly good intentions, but he can't give up the reigns of power to anybody else. He has done a lot for the poor, but he has done a fair bit of damage to the economy in the process. If not for the money he was getting from oil, his government would probably have collapsed already.
Jay