Nation-building' is an increasingly frequent activity of Western governments and the United Nations. This study examines the reconstruction of internal security institutions during nine recent nation-building missions: Panama, El Salvador, Somalia, Haiti, Bosnia, East Timor, Kosovo, Afghanistan, and Iraq. It analyzes the activities of the United States and other countries in building viable and democratic police and justice institutions. The study draws conclusions in the delivery of post-conflict security. The results should be of interest to a broad audience of policymakers and academics concerned with the successes and shortcomings of past security efforts and improving future efforts. (Published Abstract) Tables, figures, notes, and references