To whom do political parties speak to during electoral campaigns and what do they talk about? This question about party responsiveness leads my research. It could be argue that this concept of responsiveness is crucial for democracy, as parties’ role is represent citizens’ interests. It could also be argued that, to gain a comprehensive understanding of democracy, one must delve into the dynamics of elections. This necessitates grasping the primary factor shaping the behavior of involved actors: the significance of issues and agendas. Consequently, it is imperative to comprehend the interplay between actors through the examination of issues to fully comprehend democracy. The scientific literature has established that voters assign significant weight to issues, particularly regarding their salience. This implies that factors explaining voting behavior may or may not influence decision-making depending on their association with the salient issues. Political parties are well aware of this mechanism. Hence, parties are highly attentive to their strategy for emphasizing particular issues. They may seek to sway voters’ issue priorities to align with their own agenda, or they may choose to be responsive to existing voter concerns. This doctoral dissertation explores the latter scenario, advancing beyond the existing literature on party behavior. Across three papers, I aim to present innovative arguments supporting the view of parties as strategic actors.