Religious scholar Reza Aslan ponders Donald Trump, the power of pop culture and faith in America

Muslim religious scholar Reza Aslan is Internet famous for keeping his cool. The Iranian American author of the 2013 bestseller "Zealot: The Life and Times of Jesus of Nazareth" once confronted a relentless Fox News anchor with such unflappable poise, it made him a viral sensation.

After a successful...