USA has been one of the oldest democracies. It had achieved its freedom, on the basis of the principles of equality and freedom of the humans. While Iran, has transformed from a monarchical regime to an authoritarian regime. There are more differences than similarities in the governments of these two countries. The chief contrasting feature is that USA is democratic federal system, with the President as the head of the state and the government. While in Iran, the President is the head of the executive part of the government but all the decisions are taken by the religious cleric, the Leader.