This study aims to study argumentation in political debates by figuring out the logical fallacies employed in the debates of Clinton and Trump, the presidential nominees of the 2016 elections, and Biden and Trump, the leading contenders in the 2020 United States presidential election. The study attempts to answer the questions: (1) What relevance fallacies are adopted in the debate between Trump and Clinton? (2) What rhetorical devices are used to influence the audience and gain voters besides fallacies in the debates selected? The study analyses two texts from two arguments using Damer's (2009) taxonomy of relevance fallacy and rhetorical devices based on Perrine’s (1969) model of communication and interpersonal rhetoric to answer the two research questions. The significance of the pragma-rhetorical study of political debates resides in the role of investigating the pragmatic and rhetorical structure of political debates selected to encourage critical thinking, promote informed decision-making, and build a more effective and substantive political conversation. The analysis revealed that unlike Hillary, Trump uses the wrong reason, conclusion, and genetic fallacy and appeals to irrelevant authority and common opinion. Biden uses rationalisation, appealing to outside authority, and using the wrong reason. In terms of rhetoric, Trump, Clinton, and Biden all employ overstatement rather than other rhetorical devices to boost the shortcomings of their competitors and show them as unreliable in leading America in crisis. Other devices are absent except ‘understatement’, which appears for once, referring to the government's weak response to the crisis of COVID-19.
