The researcher in the video is Dr. Tamara Herold, Associate Professor at the University of Nevada, Las Vegas, and the law enforcement professional is Ryan Lee, Assistant Chief of the Portland Police Bureau. Dr. Herold notes that research indicates protests are more likely to be peaceful when law enforcement agencies adhere to a set of well-defined principles grounded in scientific research. Research indicates that de-escalation tactics are critical when law enforcement personnel are responsible for restricting the behavior of individuals and crowd members. Ryan Lee notes that the approach to crowd control by Portland police reflects research findings when it makes police goals and techniques of crowd control transparent to protesters before and during an event in which law enforcement agencies are responsible for behavioral control. When such restrictions on liberties occur, Portland police attempt to explain why such controls are being used and why the behaviors being restricted can threaten the safety of others. Police should also make clear what behaviors are appropriate for a protest and that the police are also there to guarantee the right to protest peacefully without interference from those who may disagree with them. Both Dr. Herold and Ryan Lee agree, based on research evidence, that protesters must be informed that police are present to protect protesters from harm while they make their views, complaints, and arguments known in a public place without interfering with the rights of others.