This paper by Superintendent Michael Harrison of the New Orleans Police Department explains the importance of intelligence, communication, and ample resources in policing civil disturbances.
He describes how these elements were used to prevent civil disturbances in New Orleans during the controversial removal of four Confederate monuments in 2017. This sparked some protests and counter-protests. Over the course of the removal of these monuments, there were no incidents of violence or injury to either demonstrators or police. An important part of police preparation for this project was intelligence gathering both before and during an event. For the removal of one monument, credible intelligence was received that demonstrators were planning to come with rifles and shotguns. Police snipers were deployed on surrounding rooftops, and arriving protesters were engaged by officers, who passed out copies of the law, explaining it is unlawful to carry guns at a demonstration, and pointing out the snipers in SWAT gear. The protesters complied and put away their weapons. In addition to intelligence gathering, communication is used in managing large gatherings. In New Orleans, police communicate with event organizers prior to an event to become informed of their plans and intentions, explain law on civil disturbance, and advise about the consequences of law violations. In addition, agencies are advised to deploy an excessive number of personnel and physical resources to discourage law-breaking.