On March 17, 2011, a month after the beginning of the Libyan revolution, with up to dead 2,000 civilians, the United Nations Security Council (UNSC) decided on backing a no-fly zone over Libya and authorized "all necessary measures" to protect civilians. While France, Great Britain, and the United States took immediate military action using air and missile strikes, considerations to hand over military actions to the North Atlantic Treaty Organization (NATO) emerged within days of the operation. On March 22 2012, NATO agreed to enforce the arms embargo against Libya; 2 days later, it announced to take over all military aspects of the UNSC 1973. On March 31, 2012, Operation UNIFIED PROTECTOR (OUP) began. OUP turned out to be one of NATO's shorter, and seemingly also less controversial, missions. Mandated by both the League of Arab States and the UN as the regime of Colonel Qaddafi was launching assaults on peacefully demonstrating citizens, its aim was to protect civilians from the air and sea. Described as a "war of choice" rather than a "war of necessity," NATO achieved its goals more by accident than by design, according to some critics. The lessons which can be drawn from OUP are both military and political in nature. The overestimation of air power as a result of "no boots on the ground" might be a dangerous conclusion for future cases; the lack of cultural advice very likely prolonged the mission, while the shortcomings in strategic communication gave input to improve an area that is still new to NATO. The operation also highlighted a strategic dimension the Alliance was not ready to perceive -- that the Mediterranean, and its Southern states, is likely to continue being a source of instability for NATO, particularly after the Arab Spring. In legal terms, the Alliance faced an important communication gap between its legal, and therefore military, mandate -- the legal interpretations of UNSCR 1973 made clear that the operation did not seek to topple Colonel Gaddafi's regime, let alone assassinate him. Its aim was solely the protection of civilians in a situation of internal conflict, and, therefore, it conformed to the norm of "Responsibility to Protect." On the political level, heads of NATO member states made contradictory remarks calling for Gaddafi's departure, thereby compromising the clarity of the mission. Last but not least, the aftermath of NATO's Libya operation was not planned at all as the Libyan National Transitional Council firmly rejected any military personnel on the ground, not even UN observers. As the regime's security forces had virtually imploded, Libya's security therefore fell into the hands of the multiple militias which continued to proliferate after the conflict had ended.