In his first post-election newspaper interview, with reporters from the Chicago Tribune and Los Angeles Times, Obama was asked: “Do you anticipate being sworn in as Barack Obama or Barack Hussein Obama?"
He replied: “I think the tradition is that they use all three names, and I will follow the tradition, not trying to make a statement one way or the other. I'll do what everybody else does.”
In fact, all presidents have not used their middle names when taking the oath of office. Jimmy Carter famously went as “Jimmy Carter.” Ronald Wilson Reagan took the oath as simply “Ronald Reagan.”
Harry Truman, of course, didn’t have a middle name — just an initial that didn’t stand for anything — and was sworn in as “Harry S. Truman.” (We've gotten a lot of e-mail about the period after the 'S.' Despite the urban myth to the contrary, the Harry S. Truman Library and Museum says Truman put a period in his signature and posts a photo to prove it.)
Dwight D. Eisenhower and Gerald R. Ford took the oath using their middle initials.
The last three presidents have used their middle names: George Herbert Walker Bush, William Jefferson Clinton and George Walker Bush. So did Franklin Delano Roosevelt and John Fitzgerald Kennedy.
Lyndon Baines Johnson, in the hasty ceremony aboard Air Force One, went nameless — prompted to say only, “I do solemnly swear.”