The millions of Americans who flock to Las Vegas, Atlantic City, and dozens of smaller gambling venues often say that gambling is just another form of entertainment—they view their time at a casino as no more wrong than a night at the movies or a weekend at the beach. University of Nevada English professor Felicia Campbell even argues that gambling is a spiritually uplifting experience: Gambling is “part of ‘the adventurer within us,’” she writes, “yet we treat gambling as the Victorians treated sex.”

Holding the opposite view are leaders such as Ralph Reed, former director of the Christian Coalition, who has called gambling “a cancer on the body politic, stealing food from the mouths of children, turning wives into widows.” And Americans have historically viewed gambling as a temptation to be avoided. Their...