What are the themes of The General in His Labyrinth?

The General in his Labyrinth, by Gabriel Garcia Marquez, is a fictionalized account of the last days of Simon Bolivar, dictator of what is now Colombia. There are a number of themes in the novel, themes which tend to recur in much of Garcia Marquez's work. One is isolation. Bolivar, like all dictators, and despite wielding enormous power, is isolated, all alone at the very apex of this new nation's political system. In this demythologized portrait of an historical figure, Bolivar is presented not as a legend, not as "The Liberator," but as all-too-human, sharing in the faults and foibles of us all.
Allied to the theme of solitude is that of the corruption of power. Bolivar is widely hailed as a liberator of an oppressed people from colonial enslavement. Yet as soon as he is established as dictator, Bolivar imposes a system of repression on his people with similarities to that of the Spanish colonialists. Power corrupts, and absolute power corrupts absolutely. The repressive nature of the regime instituted by Bolivar ultimately leads to the shattering of his dreams of Latin American unity. Just as he has been corrupted by power, so too has his revolutionary vision.
As the main focus of the novel is on Bolivar's last days it is inevitable that death should also be a major theme. Bolivar's death is the death of his vision, his physical decay paralleled by the crumbling hope that the project of modernity, so brutally imposed upon the people of Gran Colombia, will one day bear fruit. Bolivar dies, but his fraught and complex legacy lives on in a portion of any successive turmoils and political upheavals in Latin America.