Considering the importance of the coup and its extensive impact on the history of societies, its comparative elaboration is very insightful.
Especially, if different domestic and international parameters such as idiosyncrasy of coup junta, political parties, people attitudes, role of foreign powers, etc. are analyzed in a comparative perspective. This study seeks to examine in a comparative method the coups in Iran (1953), Guatemala (1954) and Chile (1973) and will take into consideration both external and internal dimensions. Accordingly, in addition to the study of foreign factors’ role in the fall of Mosaddegh, Arbenz and Allende’s administrations, the theoretical approach of this article is based on Gabriel Almond's theory on political system capabilities in coping with crises. Decline in a political system' s capability in coping with crises is a preliminary background for military coup to get momentum. This study, review the data through a descriptive-analytical method and based on a historical-comparative approach