At the outset of the conflict over Kosovo, the use of armed force by NATO member states has been justified to force the Government of the Federal Republic of Yugoslavia to accept and sign the Rambouillet agreement. Later on, the use of force was justified in order to prevent a major humanitarian catastrophe. But examination of the relevant Security Council resolutions and of the circumstances surrounding the Rambouillet negotiations shed a totally different light on the legal arguments advanced by proponents of NATO's intervention. Modern international law on the use of force by states, as enshrined in the UN Charter, is still at the core of inter-state relations.