The debate is spelled out right at the beginning of the film by two heavyweights in the world of evangelical Christianity. Albert Mohler, president of Southern Baptist Theological Seminary, makes his position clear: “I am convinced that the time has come for Christians to develop an exit strategy from the public schools.” Franklin Graham, son of evangelist Billy Graham and president of Samaritan’s Purse, is equally clear: “I want to see a child in every public school in America who is trained as a witness for Jesus Christ.”

So should Christians stay and fight from within, or abandon a system they perceive as broken? ...