The study identifies the rhetorical devices in some selected political speeches of President Olusegun Obasanjo, a popular Nigerian politician and an African leader with a motif to determine the strength of persuasiveness of rhetorical devices in his speeches. The study analyses some identified rhetorical devices and also examine their contextual implications within the socio-economic and political realities in Nigeria. This study explores how rhetorical devices in political speeches persuade electorates, focusing on Obasanjo’s two-term administration. Using primary data from twelve extracts of his inaugural speech, it applies Geoffrey Leech’s (2008) Linguistic and Figure of Rhetoric theory, alongside Halliday’s Systemic Functional Grammar, to analyze rhetorical patterns. The research calculates the frequency of rhetorical features to assess their persuasive impact and examines their rhetorical implicatures. A questionnaire evaluates rhetoric’s influence on voters' decisions. Findings reveal that political speeches employ rich rhetorical devices, often relying on specific lexical, syntactic, and tropic patterns to sway public opinion. Politicians strategically use language to shape support, employing rhetorical devices to depict socio-economic issues and project ideologies. The study finds they deliberately craft linguistic styles to influence public perception toward their goals. For instance, Obasanjo effectively persuaded Nigerians to back his two-term presidency through such tactics.It further concludes that the linguistic modes of Geoffrey Leech Theory of Linguistics and Figure of Rhetoric with insight from MAK. Halliday’s Systemic Functional Grammar are suitably appropriate for the analysis of rhetoric in speeches.