Dr. Lilliana Hall Mason is a professor of political science at the University of Maryland. Her research on partisan identity, partisan bias, social sorting, and American social polarization has been published in journals such as American Political Science Review, American Journal of Political Science, Public Opinion Quarterly, and Political Behavior and featured in media outlets including the New York Times, the Washington Post, CNN, and National Public Radio. She authored the book Uncivil Agreement: How Politics Became Our Identity (2018) and is co-author, with Nathan P. Kalmoe, of Radical American Partisanship: Mapping Violent Hostility, Its Causes, and the Consequences for Democracy (2022).