“Why should I bother dragging myself to church? And don’t tell me it’s because I’m obligated —says who?”   Ever felt that way? You’re in good company, because more people than ever are asking the same thing.   The truth is, church attendance has been declining across America for decades. Research from the Pew Foundation shows that the fastest-growing faith category today is “the nones”—people who claim no religious affiliation at all. They now make up about 30% of Americans.

Recently I figured out the root cause of division in America—and it’s not what you think.   The standard way to think about our divided...