After the collapse of the bipolar world' multilateral initiatives and organizations got into a crisis but at the same time their importance increased. The author analyses one form of multilateral involvement, the UN peacekeeping operations. In the last five years, their number has significantly increased. The most important among them is the one on the territory of the former Yugoslavia. Although many aspects of that operation are negative, in the future they might prove useful for the reform of the concept of peacekeeping operations. The author particularly emphasizes the necessity for these peacekeeping operations to make a shift from the prevention of hostilities towards the enforcement of peace as well as the need to separate this objective from humanitarian activities which should be assigned to specialized international organizations. The peacekeeping operations should evolve into a sort of multilateral interventionism which resolutely restricts individual states' sovereignty and strives at establishing order. They could be supplemented with other means of pressure at the UN's disposal: sanctions, diplomatic isolation or arms control.