Pete Souza, White House / MCT

Chief Justice John Roberts administers the oath of office a second time in the Map Room of the White House Wednesday.

White House Press Secretary Robert Gibbs described President Obama as “startled and perplexed” when Justice John Roberts transformed the words of the Presidential Oath of Office Tuesday.   Gibbs confirmed that President Obama memorized the words and was “startled” when the stumble occurred.   So without the 1.8 million people looking on in the cold temperatures, the oath was administered again by a robe clad Chief Justice, John Roberts.  The rare do over occurred in the in the Map Room of the White House.  Although no Bible was used in the re do, it was still binding.

The original, bungled version on Tuesday caught observers by surprise and then got replayed on cable news shows.

It happened when Obama interrupted Roberts midway through the opening line, in which the president repeats his name and solemnly swears.

Next in the oath is the phrase ” … that I will faithfully execute the office of president of the United States.” But Roberts rearranged the order of the words, not saying “faithfully” until after “president of the United States.”

That appeared to throw Obama off. He stopped abruptly at the word “execute.”

Recognizing something was off, Roberts then repeated the phrase, putting “faithfully” in the right place but without repeating “execute.”

But Obama then repeated Roberts’ original, incorrect version: “… the office of president of the United States faithfully.”

Craig, the White House lawyer, said in a statement Wednesday evening: “We believe the oath of office was administered effectively and that the president was sworn in appropriately yesterday. Yet the oath appears in the Constitution itself. And out of the abundance of caution, because there was one word out of sequence, Chief Justice John Roberts will administer the oath a second time.”

The Constitution is clear about the exact wording of the oath and as a result, some constitutional experts have said that a do-over probably wasn’t necessary but also couldn’t hurt. Two other previous presidents have repeated the oath because of similar issues, Calvin Coolidge and Chester A. Arthur.