Successful public order management is critical to upholding democracy and maintaining the rule of law. Negative police-public interactions during assemblies can impact the safety and well-being of citizens and officers, as well as local and international perceptions of police legitimacy. As observed during events across the world, including assemblies in the U.S., Myanmar, Belarus, Russia, and elsewhere, police mismanagement of mass demonstrations often instigates crowd violence and other harmful behaviors. The causes of violence at assemblies are complex and multi-faceted. Failure to understand crowd dynamics that lead to violence limits police effectiveness and contributes to poor officer decision-making.