The paper analyses the use of commissive and expressive illocutionary acts in Serbian, American and British political speeches on the topic of the standard of living, delivered between 2006 and 2014. The description of the three subcorpora includes the identification of both explicit and implicit performative linguistic devices in commissive illocutionary acts, and the identification of explicit performative linguistic devices, overt expressions of a personal stance and expressive lexis in expressive illocutionary acts. The first aim is to analyse the use of commissive and expressive illocutionary acts in political speeches. The research also aims to explain that commissive and expressive acts can be used strategically to add credibility and commitment to a declared platform for action, and vice versa, that the use or the absence of these illocutionary acts can undermine authority and credibility. The classifications based on the number of occurrences of the illocutionary force indicating devices show a preference for implicit illocutionary acts in the three subcorpora.