The presidential oath of office is required of a new president before he can execute his powers, and the Constitution is clear that its 35 words must be spoken exactly.

Which is what makes the oath President Obama took yesterday so interesting. It might be that the more than 1 million spectators didn't actually witness Obama being sworn in.

Because of a noticeable gaffe by Chief Justice John G. Roberts Jr., Obama transposed the words. He should have said he will "faithfully execute the Office of President of the United States" but instead said he will "execute the Office of President of the United States faithfully."

Constitutional law experts agree that the flub is insignificant. Yet two previous presidents -- Calvin Coolidge and Chester A. Arthur -- repeated the oath privately because of similar issues.

Lawyers said Obama and his supporters need not be worried about the legitimacy of his presidency, but they also said a do-over couldn't hurt. Charles Cooper, head of the Justice Department's Office of Legal Counsel under President Ronald Reagan, said that the oath is mandatory, that an incorrect recitation should be fixed and that he would be surprised if the oath had not already been re-administered.....

HNN Editor: William Howard Taft, in his role as Chief Justice, worried that he would make a mistake in administering the oath to Calvin Coolidge in 1925 and spoke his words extremely slowly. He was, he later confessed,"fearful as I might forget it." Four years later he did. When he administered the oath to Herbert Hoover he transposed a few words saying"preserve, maintain and protect" instead of"preserve, protect and defend." According to Paul Boller, author of Presidential Inaugurations:"The other twelve chief justices seem to have performed the ceremony without any slip-ups, including Roger Taney, who, at eighty-four, looked like a 'galvanized corpse' at his last inauguration in 1861." (p. 128)

Presidents have taken the oath twice whenever inaugurations have fallen on a Sunday. (Fearful of incurring the wrath of Sabbatarians, no one wanted the big event to occur on Sunday.) Rutherford B. Hayes in 1877 chose to take the oath at a private ceremony on Saturday attended by President Grant (inevitably raising the question of our having two presidents at the same time, though Grant's term clearly wasn't over). All other presidents facing the same dilemma chose to be sworn in on Sunday, most choosing to keep the ceremony private and secret. Some presidents held the ceremony in the Capitol (Woodrow Wilson) and some in the White House (Ronald Reagan).

Presidents do not have to repeat the words of the oath. Some have merely said:"I do."

The chief justice wasn't the only one to make a mistake yesterday. So did Obama. In his opening he referred to the"forty-four" people who have previously taken the oath, a reference to himself as the forty-fourth president. Actually, only forty-three human beings have taken the oath. President Grover Cleveland is counted twice because his terms were non-consecutive.