Objective In this project, we develop an informational theory that identifies which prime minister debates are the most meaningful in terms of shifting Spanish public opinion . We argue that debates immediately following the installation of new leaders (because they shine light on leadership traits) and debates occurring in times of crisis (because voters can judge both the leader's ability to remedy the problems and their policy proposals) will have the largest short‐ and long‐term effects. Methods We use seemingly unrelated regression to explore the impacts of 15 Spanish State of the Nation debates from 1998 to 2016 on vote intention for Partido Popular (PP) and the Partido Socialista Obrero Espanol (PSOE). Result Debates following the installation of new party leaders often produce sizable improvements in vote intention, but the most meaningful debates occur during economic crises. Conclusion Parliamentary debates are valuable opportunities for party leaders to shift public opinion in their favor, a fact that is not lost to them considering the time and energy devoted to crafting strategies, and the media's fascination with providing extensive coverage of the debates. This study has important implications for the study of dynamic processes (such as vote intention), and the link between parties' strategic communications and voting behavior.