Abstract：Abstract: Adopting the perspective of Critical Discourse Analysis and following the analytical framework of discursive strategies of legitimation developed by van Leeuwen (2008), this study examines the distribution, realization and working mechanism of discursive strategies of legitimation in 50 pieces of American presidential speeches on the Afghanistan war.. The study reveals how the discursive strategies of legitimation construct a righteous “us” and an evil “the other”, in an effort to construct a cruel and controversial war as a legitimate action with noble purposes, reasonable motivation and wide support.
