Military interventions and related peacekeeping operations are the most costly foreign policy tool. The purpose of this seminar is to examine systematically and comparatively why these policy tools are used and what results they produce on the ground. The seminar, in particular, tries to find answers to the following questions: (1) What were the broad policy arguments in favour of or opposed to a particular operation? (2) What role did international institutions play in the set-up of the operation? (3) What specific kinds of military force proved particularly useful/detrimental? (4) In each case, do we judge the operation a success or failure, and how do we explain the success or failure?