The alliance between Philippine President Ferdinand Marcos Jr and his predecessor Rodrigo Duterte disintegrated this week when they accused each other of using drugs - a rift that could threaten Marcos's reform agenda and risk fuelling instability. The alliance between two of the Philippines' most influential families that swept Marcos and Duterte's daughter, Sara, into power in 2022, was always expected to collapse, but analysts are surprised by how soon the gloves have come off. "This is a point of no return," said Jean Encinas-Franco, a political science professor at the University of the Philippines, pointing to the ferocity of the exchanges between the two families.