The aim of constitutional revolutions is creating and sustaining modern state and its institutions in the framework of the constitutional nation-state model. In this model, the national army, as one of the main institutions of state, has an important role in establishment the sovereignty and the monopoly of legitimate force. But the constitutional movement in Iran and its supporters, despite the overthrow of the ancient regime, failed in the establishment efficient and powerful institutions of a modern state. This inability was obvious in create a national army. The causes of this failure were social and political structures and agent of the constitutional movement. The weaknesses of social structures and ignorance of the agent detained constitutional revolution from establishing a national army in Iran. These inabilities to establish a strong central state in turn finally bring about the failure of the constitution movement and to give up at least part of constitutional ideals.