The policing of demonstrations is a crucial activity that reveals much about the quality of democracy in a given society. In addition to presenting the papers that make up the dossier, this article contributes to Northern Ireland's accumulated experience in dealing with demonstrations. Brazil and Northern Ireland constitute divided societies in which the police is co-responsible for conflicts and face serious legitimacy problems, at least for vulnerable groups. Lessons from Northern Ireland indicate that mutual understanding between police and protesters is vital to limit the potential for public order incidents and events to become unmanageable
