This article investigates why President Obama in 2011 ordered US air and naval forces to launch Operation Odyssey Dawn in Libya. The president's decision was the result of a combination of factors, including feelings of altruism, the legal basis for the operation, international support, domestic political constraints and the possibility to limit U.S. participation. The case study attempt to trace the process by which Obama came to the decision to use force in Libya by relying on a multitude of different sources, such as government reports, speeches and remarks, parliamentary records, media coverage, secondary sources.