Obama retakes oath of office

After the bungle heard around the world, US President Barack Obama has taken the oath of office. Again.

In a highly unusual move, Supreme Court Chief Justice John Roberts delivered the oath to Obama a second time at the White House on Wednesday night.

The rare repeat came in response to Tuesday's much-noticed stumble, when Roberts got the words of the oath a little off, which prompted Obama to do so as well.

Don't worry, the White House says: Obama has still been president since noon on Inauguration Day.

Nevertheless, Obama and Roberts went through the drill again out of what White House counsel Greg Craig called "an abundance of caution".

This time, the scene was the White House Map Room in front of a small group of reporters, not the Capitol platform before the whole watching world.

"We decided that because it was so much fun ...," Obama joked to reporters who followed press secretary Robert Gibbs into the room.

No television camera crews or news photographers were allowed in.

Roberts put on his black robe.

"Are you ready to take the oath?" he said.

"Yes, I am," Obama said.

"And we're going to do it very slowly."

Roberts then led Obama through the oath - and they got it word-perfect this time.

The president said he did not have his Bible with him but that the oath was binding anyway.

The original, bungled version on Tuesday caught observers by surprise and then got replayed on television 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".

Recognising 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.

Craig, the White House lawyer, said in a statement on 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.