First Generation
Revival
Second Generation
Composition
Use of Force
Consent of the Parties
Ceasefire Prerequisite

Important changes have occurred in Peacekeeping, to adapt to evolving conditions and to carry out missions in a more efficient and effective way. There are two main categories of changes:

The evolution of PKOs can be divided into three different phases:

First Generation

First Generation missions were deployed soon after WWII to fulfill the UN mandate to guarantee international peace and security. Some of those first missions are still operating. In 1947 a United Nations Special Committee on the Balkans was established in response to the civil war in Greece. The Arab-Israeli conflict and the Indo-Pakistani war over Kashmir required the deployment of the first operations (respectively, UNTSO and UNMOGIP) with functions of monitoring ceasefires and reporting on the situation. UNEF1 was the first armed mission and the first to be labeled Peacekeeping. It was organized in 1956 to monitor the withdrawal of British, French and Israeli forces from the Suez Canal.

The subsequent First Generation missions followed the model of intervention developed in the initial cases, with limited means and a limited mandate, maintaining a neutral position and essentially with the sole function of monitoring the situation. An important exception was the 1961 intervention in Congo. The United Nations Operation in Congo (UNOC) had been the largest PKO until the 1990s. An anticipation of the future evolution of Peacekeeping, it was the first intervention under conditions of violent civil conflict and the first case of transition from Peacekeeping to peace enforcement, involving the use of force as authorized by the UN Security Council. Because of the violence involved, and the ambiguity concerning the mandate of the operation, for a long time UNOC was also an example of how Peacekeeping should not work. All subsequent missions were limited in number and scope, and no new operation was established between 1978 and 1988.

Revival

Revival of PKOs began in 1988, essentially as a result of the easing of East-West tensions inside and outside the Security Council. UN missions supervised the dismissal of some of the last vestiges of the Cold War, monitoring the withdrawal of Soviet troops from Afghanistan and of Cuban troops from Angola. The first operation with large participation of civilians was organized in 1989 to organize political elections and favor the transition to democracy in Angola.

Second Generation

Second Generation PKOs started by 1992 with a set of large and complex missions that were deployed in Somalia, Cambodia, Mozambique and the former Yugoslavia. These operations were qualitatively and quantitatively different. They employed large military and civilian personnel. They were the first examples of multifunctional missions in which political, military, humanitarian, and electoral components were coordinated and fully integrated. Operations in the former Yugoslavia and in Somalia were authorized by the Security Council under chapter VII, to use force in the implementation of their humanitarian mandate.

Composition of the Contingents

First Generation Peacekeeping missions were generally composed of small military contingents, lightly armed, from contributions of many different countries, following principles of balanced geographic distribution. In the majority of cases the peacekeepers were provided by neutral or non-aligned countries.

Second Generation missions are composed of both civilian and military personnel; military contingents are larger and armed to defend their security in conditions of diffused violence. The composition of the contingents does not consider geographic representation as a priority; more attention is attached to interoperability, efficiency, and unity of command and control structures. Major countries with adequate military and financial capabilities provide large contingents of peacekeepers.

Use of Force

First Generation peacekeepers were not authorized to use force to fulfill their mandate; force was only to be used for self-defense. In the more complex and dangerous missions of Second Generation peacekeepers are regularly authorized to use force in the context of their mandate. The humanitarian mission in Northern Iraq (Resolution 688) was the first mission authorized to use force, not as a measure of peace enforcement but to guarantee the protection of the population and the delivery of assistance. The mission to Somalia (Resolution 733) was authorized the use of force in order to fulfill the tasks of disarming the fighting factions and distributing humanitarian aid. The change in mandate transformed the Peacekeeping missions into something closer to peace-enforcement. From then on, all other PKOs are directly authorized to use force for the fulfillment of their mandate. It became a commonly accepted procedure, as early as 1992, as it was suggested in An Agenda for Peace: "Before deployment takes place, the Council should keep open the option of considering in advance collective measures, possibly including those under Chapter VII when a threat to international peace and security is also involved, to come into effect should the purpose of the United Nations operations systematically be frustrated and hostilities occur."

Consent of the Parties

The consent of the parties involved in the conflict ensured First Generation PKOs a relatively stable operational environment. Missions are significantly more complicated and dangerous when the consent is only partial or limited to only one (or two) of the parties in the conflict. Frequently in Second Generation PKOs splinter groups, irregular militias and smaller factions either do not respect the ceasefires, disagree with the major parties or act independently. In the case of minor resistance, consisting of isolated acts of violence and banditry, if the major parties support the PKO, the personnel can be empowered to deal with the situation on the basis of self-defense, and backed by clear rules of engagement. The case differs when one or more of the major parties do not agree with the international deployment or withdraw their support. In the first case the military personnel is called to maintain order and perform policing activities, in the second case the mission mandate could switch toward peace-enforcement, involving military operations against one or more of the parties.

Ceasefire Prerequisite

Traditionally First Generation forces were deployed once a temporary agreement between the parties was reached, and a ceasefire allowed for the continuation of a pacific peace process and the beginning of the reconstruction process. In Second Generation PKOs however, military forces are often deployed in conditions of instability. PKOs can play a role both in Peacemaking and Conflict Prevention, blurring the line between PK and Peace enforcement. PKOs usually start as a conflict is winding down and help ensure that there is no further escalation. Once peace is reached, PKOs can be extended into the process of post-conflict reconstruction and Peacebuilding.