On this day in 1956, two years after pushing to have the phrase "under God" inserted into the pledge of allegiance, President Dwight D. Eisenhower signs a law officially declaring "In God We Trust" to be the nation's official motto. The law, P.L. 84-140, also mandated that the phrase be printed on all American paper currency. The phrase had been placed on U.S. coins since the Civil War when, according to the historical association of the United States Treasury, religious sentiment reached a peak. Eisenhower's treasury secretary, George Humphrey, had suggested adding the phrase to paper currency as well.
Although some historical accounts claim Eisenhower was raised a Jehovah's Witness, most presidential scholars now believe his family was Mennonite. Either way, Eisenhower abandoned his family's religion before entering the Army, and took the unusual step of being baptized relatively late in his adult life as a Presbyterian. The baptism took place in 1953, barely a year into his first term as president.
Although Eisenhower embraced religion, biographers insist he never intended to force his beliefs on anyone. In fact, the chapel-like structure near where he and his wife Mamie are buried on the grounds of his presidential library is called the "Place of Meditation" and is intentionally inter-denominational. At a Flag Day speech in 1954, he elaborated on his feelings about the place of religion in public life when he discussed why he had wanted to include "under God" in the pledge of allegiance: "In this way we are reaffirming the transcendence of religious faith in America's heritage and future; in this way we shall constantly strengthen those spiritual weapons which forever will be our country's most powerful resource in peace and war."
The first paper money with the phrase "In God We Trust" was not printed until 1957. Since then, religious and secular groups have argued over the appropriateness and constitutionality of a motto that mentions "God," considering the founding fathers dedication to maintaining the separation of church and state.
Taken from: http://www.history.com/this-day-in-history/president-eisenhower-signs-in-god-we-trust-into-law [30.07.2012]