Due to the ever-changing political scene and the increasing effect of political language on people's perception, linguistic analysis is inevitable to understand political matters. By using myths in speeches, politicians legitimise specific political actions and motivate the public to accept these actions This study inspects the concept of 'Political Myth' by Bottici (2007) within the framework of Discourse Historical Approach [DHA] and Van Leeuwen's model of Social Actor's Representation. The present study examines the utilisation of the political myth of Conspiracism in Trump's Immigration speech to legitimize the rejection of refugees. The USA, known as the land of opportunities, has a long history of rejecting refugees and immigrants based on the myth of Conspiracism. In the famous Immigration speech, former President, Donald Trump, relied on promoting anti-immigrant sentiments to justify rejecting refugees. The data under study comprises extracts that referred to immigrants/refugees and American citizens. This paper attempts to answer the questions: What is meant by Political Myth? What are the principles of the political myth of Conspiracism? What are the referential strategies used to depict the in-group and the out-group? To what extent did the depiction of the in-group and the out-group fulfil the principles of the myth of Conspiracism?. Overall, this study indicates the usefulness of examining political myth to understand the political status quo. Also, it sheds light on the importance of linguistic analysis to decipher and evaluate politicians' actions.