Chris Zurn is a philosophy professor at University of Massachusetts Boston. He led a 2017 discussion about the ethics of antifa tactics for a series put on by the university’s Applied Ethics Center.

Alan Zimmerman is the immediate past president of Congregation Beth Israel in Charlottesville, Virginia. He wrote about his congregation’s experience during the August 2017 “Unite the Right” protest.

Zeynep Tufekci is a sociology professor at the University of North Carolina at Chapel Hill. She wrote “Twitter and Tear Gas: The Power and Fragility of Networked Protest.”

David Snyder is the executive director of the First Amendment Coalition. He comments on free speech issues.

Peter Simi is a sociology professor at Chapman University and has studied extremist groups and violence for more than two decades.

Arie Perliger is a security studies professor at University of Massachusetts Lowell. His research interests include political violence and extremism.

J.J. MacNab is a fellow with the Program on Extremism at George Washington University. MacNab is an expert on sovereign citizens, paramilitary militia groups and anti-government extremist organizations.

Darren Linvill is a Clemson University professor who researches disinformation on social media.

Gary LaFree is the founding director of the National Consortium for the Study of Terrorism and Responses to Terrorism at the University of Maryland. He created the Global Terrorism Database.