As part of their continuous effort to enhance the effectiveness and democratic legitimacy of human rights treaties, human rights treaty organs have increasingly fostered a direct relationship with various state organs, thereby penetrating the ‘states’ that traditionally have been treated as monolithic legal entities. Treaty organs review the decision-making process of each type of state organ – courts, parliaments and administrative organs – and make remedial orders that are substantially addressed to specific state organs. Such phenomena go hand in hand with the relativization of the distinction between the legal spheres in which human rights treaty organs and state organs operate. This is the first study to address such phenomena as a totality. It constructs the ‘separation of powers in a globalized democratic society’ theory, thereby proposing how each type of state organ and the treaty organs should interact under human rights treaties. Its findings contribute, first, to the harmonious achievement of the effectiveness and democratic legitimacy of human rights treaties; second, to the reform of the classical paradigm of international law, in which monolithic states are the only relevant legal entities; and third, to the long-standing debates on the relationship between international and national laws from a new angle.