Thomas Foster recounts the history of "In God We Trust":
Only the motto "E Pluribus Unum" ("from many, one") survived the committee in which Adams, Jefferson, and Franklin had served. All had agreed on that motto from the beginning. The current motto, "In God We Trust," was developed by a later generation. It was used on some coinage at the height of religious fervor during the upheaval of the Civil War. It was made the official national motto in 1956, at the height of the Cold War, to signal opposition to the feared secularizing ideology of communism.
In other words, "In God We Trust" is a legacy of founders, but not the founders of the nation. As the official national motto, it is a legacy of the founders of modern American conservatism—a legacy reaffirmed by the current Congress.
The Dish 