ANSWER
1954
When Francis Bellamy wrote the Pledge of Allegiance in 1892, it did not contain the words "under God". The Civil War was the most prominent event in the lives of Bellamy and his contemporaries, and Bellamy's goal was to create a pledge to "One Nation". In his own words: "To make that One Nation idea clear, we must specify that it is indivisible." The central idea behind Bellamy's pledge was not so much "one nation under God", but rather it was "one nation - indivisible".
Nearly sixty years later, the Knights of Columbus began adding the phrase "under God" in their meetings, and began lobbying Congress to officially adopt this change for the rest of the country. Their efforts were successful. President Dwight Eisenhower signed the change into law on Flag Day, June 14th, 1954.
(Just to make the origins of the Pledge of Allegiance a little more interesting, it should be pointed out that Francis Bellamy was also a Baptist minister. And a Socialist.)
WHO GOT IT RIGHT: Ryan Scannell, Bob Milligan, Tim Westcott, Moana Kutsche, Steve Shuba, JP Weigt, Allan Christensen, Mark Collins, Marc Quinlivan, and Iron Saul.
