Many studies have introduced John Patrick Shanley's Doubt: A Parable (2005) from different perspectives; however, reading the play from the New-Historicist approach properly serves the main purpose of the paper which is to highlight the reciprocal relationship between history and the literary text. Therefore, the literary text is not a self-contained entity but rather a culturally and historically-oriented product. Investigated from the New-Historicist approach, specifically focusing on Michel Foucault who has had a wide-range impact on the development of New Historicism through his power relations conception, Shanley's Doubt is seen as an "allegorical" portrayal of a crucial historical event: the United States' invasion of Iraq (2003), by implicitly depicting factual historical characters as well as juxtaposing them with historical, social and cultural factors (Cullingford 258). In this respect, this paper explores Shanley's play not as a referential context of the "power of individuals" but of the "power of institutions" run by individuals, in Foucault's terms.