Barack retook the oath, last night, from Justice Roberts, "out of an abundance of caution."
Barack's original oath wasn’t the oath associated with the office. Barack took an oath Justice Roberts accidentally concocted, and which may as well have been concocted and sworn to over beers at a tavern.
I don't know the legalities of taking the proper oath (and apparently such is up for grabs anyway). To me, taking the oath is about honor, self declaration, principle, a sacred bond. Such a thing is a statement of who you are as a person. It’s kind of like voting: your vote - during your entire life - is never going to functionally make a danged bit of difference in any election. Voting is not about functionally making a difference. Voting is a solemn declaration of who you are. Taking the Presidential Oath is making a sacred bond with the people of the nation. I’m actually more interested in Barack’s sacred bond with me, with all of us, than I am interested in functional legalities.
Fun Fact from Dave Wiegel:
Barack is first President to be sworn in by a Chief Justice he voted against confirming.