This chapter develops the conceptual basis and theoretical framework for the study, relating to relevant literatures in intelligence studies, peace studies and constructivist theories in IR. It discusses normative versus analytical approaches to warnings in foreign affairs and explicates problematic assumptions in the literature. It argues that warnings come in various forms and may contain a variable mix of knowledge, relevance and action claims. They can differ greatly in their senders’ intentions and relationships to recipients. Therefore, warning impact needs to be measured in a more nuanced way than whether warnings led to effective preventive action. The chapter develops a theoretical framework that draws on the most relevant insights from literatures in social psychology, advocacy and political communication to explain when warnings are persuasive. It distinguishes between outside-in warnings from NGOs and news media and inside-up warnings through intelligence analysts and diplomats. The framework elaborates which variables can best account for differences in persuasive success and how they may interact.