Political leaders need ministers to help them rule and so conventional wisdom suggests that leaders appoint competent ministers to their cabinet. This book shows this is not necessarily the case. It examines the conditions that facilitate survival in ministerial office and how they are linked to ministerial competence, the political survival of heads of government and the nature of political institutions. Presenting a formal theory of political survival in the cabinet, it systematically analyses the tenure in office of more than 7,300 ministers of foreign affairs covering more than 180 countries spanning the years 1696-2004. In doing so, it sheds light not only on studies of ministerial change but also on diplomacy, the occurrence of war, and the democratic peace in international relations.This text will be of key interest to students of comparative executive government, comparative foreign policy, political elites, and more broadly to comparative politics, political economy, political history and international relations.