The enactment of the Water Services Bill into Irish law on December 28, 2014, was met with strong opposition from the Irish public, manifesting in local and national demonstrations. This social movement provided an ideal case to examine interactions between protesters and police in different contexts. Ethnographic observations and randomly sampled interviews took place before, and during, seven national demonstrations in Dublin, Ireland. Simultaneously, urban ethnographic research yielded in-depth observational and interview data at local protests in another Irish city. Data from both national and local protests are examined in light of classical and contemporary sociocultural psychological conceptualizations of the crowd. The elaborated social identity model offers most explanatory power to comprehend the observed and reported events between police and protesters in this cultural context during an unprecedented economic recovery following recession. No evidence is found to support classical conceptualizations of the crowd. I describe the consequences of this analysis for conceptualizing police–protester interactions to generate peaceful assembly in liberal democracies.