"The words 'under God' in the Pledge of Allegiance and the phrase 'In God we trust' on the back of a dollar bill haven't been there as long as most Americans might think. Those references were inserted in the 1950s during the Eisenhower administration, the same decade that the National Prayer Breakfast was launched, according to writer Kevin Kruse. His new book is One Nation Under God."

"In the original Pledge of Allegiance, Francis Bellamy made no mention of God, Kruse says. Bellamy was Christian socialist, a Baptist who believed in the separation of church and state."

"'As this new religious revival is sweeping the country and taking on new political tones, the phrase 'one nation under God' seizes the national imagination,' Kruse tells Fresh Air's Terry Gross. "It starts with a proposal by the Knights of Columbus, the Catholic lay organization, to add the phrase 'under God' to the Pledge of Allegiance. Their initial campaign doesn't go anywhere but once Eisenhower's own pastor endorses it ... it catches fire.'"