WASHINGTON (CNN) — While the White House has taken some heat for choosing not to attend an event marking the 150th anniversary of President Abraham Lincoln delivering the Gettysburg Address, it's President Barack Obama's recitation of the famed speech that's bringing up a true American controversy: Which of the five versions of the speech is correct?
Obama, a long-time admirer of Lincoln, recorded the speech as part of a project sponsored by PBS. He was one of 57 notable figures - including past Presidents George W. Bush, Bill Clinton and Jimmy Carter, Sen. Marco Rubio, director Steven Spielberg and CNN's Wolf Blitzer -- who recited the speech as part of a national public outreach campaign to encourage people to learn and recite the address in celebration of its 150th anniversary.
The president was the only person to tape a version, known as the 'Nicolay' version, which perhaps most notably is one that does not include "under God" in the second to last sentence. The selection came at the request of the documentarian Ken Burns, who has a team heading up the project. One of the producers told CNN they gave Obama this version to use to highlight that there are multiple versions.
White House Press Secretary Jay Carney confirmed the producer's account, saying Tuesday the President "read the version of the address...Ken Burns provided." Carney added that was the Nicolay manuscript of the speech.
The other speakers recited what the Library of Congress calls the "standard text." In that version, the last sentence reads: "It is rather for us to be here dedicated to the great task remaining before us-that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion-that we here highly resolve that these dead shall not have died in vain, that this nation under God shall have a new birth of freedom, and that government of the people, by the people, for the people shall not perish from the earth."
The use of "under God" in the Gettysburg Address has an uncertain history. Of the five manuscript copies of the address, three contain the phrase and two do not.
The versions held in the Library of Congress -- given by Lincoln to his two private secretaries -- do not include the phrase "under God." Those copies, known as the Hay and Nicolay versions, are thought to pre-date the remaining three copies of the text, which Lincoln wrote out for charity well after the November 19, 1863 address. Those later versions all contain the "under God" expression. President Obama read, word for word, the Nicolay version of the speech.
The inscription of the Gettysburg Address at the Lincoln Memorial in Washington contains the words "under God," and contemporary transcriptions of the address by newspaper reporters also include it.
President George H.W. Bush, former New York Mayor David Dinkins, singers Taylor Swift and Usher were among the celebrities included in a mashup of the speech also posted on the website learntheaddress.org.
The National Park Service will hold a ceremony in Gettysburg on Tuesday to commemorate the address and Interior Secretary Sally Jewell will attend. Press Secretary Jay Carney did not respond directly to questions about why the president, who has twice been sworn into office using president Lincoln's Bible and who announced his bid for the presidency in Lincoln's adopted hometown of Springfield, Illinois, was not planning to attend the event.
"Obviously that address and that moment in time is seminal in our history and I think that all Americans across the country will have the opportunity to think about those words and that address," Carney said.
The PBS campaign is inspired by the subject of Burns' upcoming film The Address, about a small school in Vermont where students are encouraged to memorize, practice and recite the address, which the website calls "one of the most important declarations ever made on human equality."
The President penned a tribute to the Gettysburg address on Tuesday. In the hand-written note, Obama describes visiting a room in the White House that Lincoln once used as an office. An original copy of the famous speech is on display in the room.
"I linger on these few words that have helped define our American experiment: 'a new nation, conceived in liberty, and dedicated to the proposition that all men are created equal,'" Obama writes.
"Through the lines of weariness etched in his face, we know Lincoln grasped, perhaps more than anyone, the burdens required to give these words meaning."
Obama continues: "He understood as well that our humble efforts, our individual ambitions, are ultimately not what matter; rather, it is through the accumulated toil and sacrifice of ordinary men and women - those like the soldiers who consecrated that battlefield - that this country is built, and freedom preserved. This quintessentially self made man, fierce in his belief in honest work and the striving spirit at the heart of America, believed that it falls to each generation, collectively, to share in that toil and sacrifice."