Introduction During the Cold War, traditional United Nations (UN) peacekeeping operations had to cope with cases of international conflict, which required the UN to monitor ceasefire agreements and buffer zones. This first generation of peacekeeping operations was followed by new missions with new goals when the global order evolved. With the end of the Cold War, the UN has become involved in a second generation of peacekeeping operations, related to domestic rather than international conflicts, and requiring civilian administrations and policemen, as well as soldiers, to oversee the implementation of peace plans negotiated by the parties in conflict that have agreed to resolve their disputes at the ballot box. (1) In each case, the parties involved had earlier accepted the UN presence and, therefore, UN peacekeepers only used force to defend themselves. Meanwhile, a third generation of peacekeeping operations, which did not require the consent of the parties involved, has emerged under Chapter VII of the UN Charter. Th is development overlapped with the appearance of coalitions of the willing with a mandate from the Security Council to undertake specific enforcement actions, such as the International Force East Timor (INTERFET). It was against this background that a UN mission was undertaken in East Timor, a mission seen by some as the precursor of a fourth generation of state-building operations, (2) and by others as a classic case of decolonization. (3) The UN Transitional Administration in East Timor (UNTAET) was established by UN Security Council Resolution 1272 on 25 October 1999, endowed with overall responsibility for the of the territory and empowered to exercise all legislative and executive authority, including the of justice, during the period of transition from Indonesian until formal independence. At the same time, it also had many other tasks to accomplish, such as providing security, maintaining law and order, establishing an effective administration, assisting in the development of civil and social services, ensuring the co-ordination and delivery of humanitarian assistance, rehabilitation and development assistance, supporting capacity-building for self-government, and as sisting in the establishment of conditions for sustainable development. UNTAET's scope of responsibilities and the range of the mandate were without any precedent in the peacekeeping or peacemaking operations that came before (UNMIK [UN Interim Administration in Kosovo] is the only, but partial, exception). For the first time, the UN had sovereign control over a trust territory, and UNTAET was a trusteeship administration preparing a territory for independence. (4) In other words, there was a combination of UN governorship with the strategic objective of independent statehood. (5) As such, it was a state-building mission, and this was viewed by many as a test case. In fact, it was considered that UNTAET would have to invent a functioning state of East Timor. (6) Between October 1999 and May 2002, the territory became a laboratory for an experiment of governance, and UNTAET was the de facto sovereign in the territory. With so much at stake, and now that UNTAET's mandate has expired, it is apt to evaluate its performance. Some questions are particularly relevant. What were the results of the experiment? Did it accomplish the goals established by UN Security Council Resolution 1272? Were there any lessons learned from this experience? What kind of legacy did it leave in the new sovereign state of East Timor? The Establishment of UNTAET In 1999, after twenty-four years of occupation, Indonesia finally allowed a popular consultation -- Jakarta refused to call it what it really was, a referendum -- to take place in East Timor. (7) The United Nations Mission in East Timor (UNAMET) was responsible for the organization and conduct of the popular consultation, on the basis of a direct, secret, and universal ballot. …