President Eisenhower made it legal in 1956:
"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."It was a good day for the US.
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