Summary

Peacekeeping has evolved both in its focus and in setting increasingly ambitious goals. In effect, the referent object of peacekeeping—what and whose peace is to be kept—has changed. The peace that is to be kept has evolved from a negative conception of peace to encompassing an increasingly positive understanding of peace. Similarly, the object of the peace has shifted from the global to the national, and ultimately to the local. In effect, this has raised the bar for peacekeeping.

Peacekeeping research has mirrored these changes in the expectations and practice of peacekeeping, where the (in)effectiveness of peacekeeping has remained a constant concern. The evaluation has shifted from the authorization and organization of peacekeeping missions to the impact of peacekeepers in avoiding the recurrence of conflict, to ultimately the ability of peacekeepers to change the situation on the ground as well as the interaction between peacekeepers and the local population.

Research on peacekeeping has become increasingly methodologically sophisticated. Originally, qualitative case studies provided a largely critical evaluation of the effect of peacekeeping. Large-n quantitative studies have reassessed where peacekeepers are deployed and who provides peacekeepers. Controlling for selection bias and possible endogeneity, quantitative research finds that peacekeeping makes the recurrence of conflict less likely. Disaggregate data on peacekeeping confirm that peacekeeping contains local conflict and protects local civilian populations. At the same time, peacekeepers have had only limited success in positively affecting conflict societies by means of security sector reform and building state capacity. There is little evidence that peacekeeping is able to support democratization and economic development.