According to records compiled by the Architect of the Capitol and maintained by the Library of Congress, Theodore Roosevelt did not use a Bible at his 1901 swearing-in, the Washington Post reported. And in 1963, when Lyndon B Johnson was sworn in on Air Force One at Love Field airport in Dallas after the assassination of President John F Kennedy, he used a Roman Catholic missal, a liturgical text.
"I had given this Bible or missal to the judge on Air Force One, which I had taken off the side table in the president's bedroom in Air Force One," Democratic strategist Lawrence F O'Brien, a Kennedy aide, recalled in an oral history interview with Johnson's presidential library in 1986.
It turned out not to be a Bible, though it was "a book with a cross on the cover, leather-bound" and new.
The use of the Bible at presidential swearings-in is a matter of tradition rather than law, according to experts. "That tradition just was begun by George Washington and has been pursued ever since, but there's nothing in the Constitution that says anything about a Bible," said Laurence Tribe, a constitutional scholar at Harvard Law School and an informal adviser to Obama.
The oath itself, however, is the only oath whose exact terms are specified in the Constitution, The Post reported. But Tribe noted that when it has been misstated and not corrected, nothing happens, as the presidency automatically transfers to the elected successor upon the
departure of the previous president from the White House.
Obama is the seventh president to have restated his oath of office. Four Rutherford B Hayes, Woodrow Wilson, Dwight D Eisenhower and Ronald Reagan in 1985 restated their oaths publicly because in those years Jan 20 fell on a Sunday, meaning only private ceremonies were held on those Inauguration Days.