Vivienne Walt explains:
One crucial error by Western leaders, says [Mustafa Fetouri, director of the M.B.A. program at the Academy of Graduate Studies in Tripoli], has been to downplay Libya's complex web of tribal loyalties, which has helped to keep Gaddafi in power for more than four decades an impressive achievement, given several assassination attempts and years of Libya being an international pariah under stiff economic sanctions.
Some tribal alliances date back decades to the bloody rebellions against the Italian colonial forces before World War II, and even some tribal leaders who hold grudges against Gaddafi, for having failed to deliver services or cutting them out of certain privileges, rushed to his defense once the antigovernment demonstrations in Benghazi became an armed rebellion. For those people, says Fetouri, "they will die for Gaddafi, because he belongs to their tribe."