Description:President Barack Obama is promising to uphold the Constitution in a public swearing in ceremony that signals the beginning of his second term in office.
Placing his hand on two Bibles -- one used by President Abraham Lincoln at his first Inauguration and one used by the Reverend Dr. Martin Luther King, Jr. -- Obama took a public oath of office on Monday, after he was sworn in during a private ceremony on Sunday. The Constitution requires presidential terms to begin on Jan. 20.(1:49)