- Julian Zelizer: Donald Trump's embrace of the politics of fear echoes a dangerous tradition
- Other Republican candidates need to explain where they stand on the issues that Trump has raised
Julian Zelizer is a professor of history and public affairs at Princeton University and a New America fellow. He is the author of "Jimmy Carter" and "The Fierce Urgency of Now: Lyndon Johnson, Congress, and the Battle for the Great Society." The opinions expressed in this commentary are solely those of the author.
(CNN)When Republicans gather for their next debate Tuesday, one of the main issues all the candidates should be required to address is what each thinks of the controversial statements and arguments that Donald Trump has made about how to fight ISIS.