From an interdisciplinary framework anchored theoretically in Critical Discourse Analysis and using analytical tools from Systemic Functional Linguistics, this article accounts for a crucial use of language in society: the process of legitimization. This article explains specific linguistic ways in which language represents an instrument of control (Hodge and Kress, 1993: 6) and manifests symbolic power (Bourdieu, 2001) in discourse and society. Taking into account previous studies on legitimization (i.e. Martín Rojo and Van Dijk, 1997; Van Dijk, 2005; Van Leeuwen, 1996, 2007, 2008; Van Leeuwen and Wodak, 1999), this particular work develops and proposes some key strategies of legitimization employed by social actors to justify courses of action. The strategies of legitimization can be used individually or in combination with others, and justify social practices through: (1) emotions (particularly fear), (2) a hypothetical future, (3) rationality, (4) voices of expertise and (5) altruism. This article explains how these strategies are linguistically constructed and shaped. This study explains the use of these discursive structures and strategies through examples of speeches given by leaders with differing ideologies, specifically George W. Bush and Barack Obama, in two different armed conflicts, Iraq (2007) and Afghanistan (2009), to underline their justifications of military presence in the notorious 'War on Terror'.