Why did Congress order the motto In God We Trust be placed on American currency?

Answer 1

The motto "In God We Trust" was first used during the US Civil War as an expression of religious faith during that terrible conflict. It can be traced back to a stanza of the Star-Spangled Banner written during the War of 1812: "And this be our motto: 'In God is our Trust.' "

The phrase was adopted as a battle cry at the Battle of Anteitam in 1862, and a movement grew to recognize the wording in some form on coins, in part to show that God was on the side of the Union and against the Confederacy.

When the Mint introduced a new 2¢ denomination in 1864 Secretary of the Treasury Salmon P. Chase directed that the design include the motto, but in the shortened form that we know today. It was placed on most other denominations of coins in 1866. Its use wasn't universal, though; for example the motto was removed from the nickel in 1883 and wasn't restored until 1938.

Strangely enough the motto was never put on paper money at the same time. Nine decades later a similar set of political opinions coalesced in search of a way to differentiate the US from the "Godless communists" of the Soviet Union and "Red" China, leading to its adoption as the national motto in 1956. It was added to paper money starting with the 1935G and 1957 series of $1 bills, and was put on all other denominations starting in 1963.

Despite the fact that the motto doesn't refer to any particular religion and is seen as rather innocuous by most people, its use has been contentious among those at the far ends of the religious spectrum. Over the years various secular groups have unsuccessfully sued to have it removed from currency, while other extremely religious organizations have counter-lobbied to make its use more prominent.

Answer 2

Congress ordered the motto to be used on coins first in 1908 (though the penny and nickel were excluded) but was first used on coins before that in response to increased religious passion during and following the American Civil war, it was required in 1955 by act of congress to be on all American coins and currency to differentiate the generally religious people of the US from the atheistic people in communist countries.