In 1956, President Eisenhower signed a law that changed the national motto of the United States from "E Pluribus Unum" to "In God We Trust"
The change was uncontroversial at the time, and largely prompted by the cold war.
There are some constitutional questions though, because the First Amendment emphasizes separation of church and state.
Personally I think that E Pluribus Unum (From Many, One) is a way better motto.
As an atheist, I feel excluded by the current motto.
Also, shouldn't we be emphasizing our roots as a people united in control of our fate?
To me, "In God We Trust" sounds like its taking control away from the people, and very un-democratic.