This analysis examines resolutions authorising peace missions and their extensions at the United Nations Security Council (UNSC) from 1948 to early 2024. Our study investigates coalitions involving the five permanent members (P5) and the ten elected non-permanent members (E10). By combining quantitative voting behaviour analysis with qualitative assessments of selected resolutions and related statements, we pay particular attention to abstentions. Various coalition-formation approaches reveal insights into the dynamics of these coalitions. It becomes clear that traditional theoretical approaches must be adapted for the UNSC, as coalition formation is influenced by factors such as national interests, anticipated audience costs (including the effects on a member state’s standing within the organisation), and the desire to maintain the institution’s collective legitimacy and credibility.