Due to the well noted flub of the oath of office on inauguration day (in front of a few billion people) John Roberts and Barack Obama had a do-ever Wednesday just to be sure. You'd think a couple of Harvard Law types could get it right the first time. He is third president to do so.
This was done out of "an abundance of caution" since the conspiracy theorists have started to claim that he was not really president and that this all part of a plot to undermine the union, or the Obama Presidency or both.
Conspiracies aside, there's an interesting question regarding whether the do-over was necessary. The body of the Constitution (Article 2, Section 1, the last bit) states that:
Before he enter on the Execution of his Office, he shall take the following Oath or Affirmation:--''I do solemnly swear (or affirm) that I will faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States.''
This makes it seem that the oath or affirmation is neceesary, Section 1 of the 20th Amendment (which changes the day that the president is sworn in) states this:
The terms of the President and Vice President shall end at noon on the 20th day of January, and the terms of Senators and Representatives at noon on the 3d day of January, of the years in which such terms would have ended if this article had not been ratified; and the terms of their successors shall then begin.
It doesn't say anything about an oath or affirmation. Does it mean that it is no longer legally required? That it's just a neat ceremony to kick off a presidency? Or does it leave the requirement in place? How might this be interpreted by the courts? To further complicate the matter, remember that the Chief Justice is a member of the court that has the final say over the oath's requirement.
As fun as it might be to figure this things oath, there seem to be more pressing concerns on the governmental agenda. So its perhaps best it was done over.