U.S President Barack Obama (L) takes the oath of office from U.S. Supreme Court Chief Justice John Roberts (R) as first lady Michelle Obama (2nd L) holds the bible and daughter Malia (C) and Sasha looks on in the Blue Room of the White House January 20, 2013 in Washington, DC. Obama and U.S. Vice President Joe Biden were officially sworn in a day before the ceremonial inaugural swearing-in. (Photo by Larry Downing-Pool/Getty Images)

WASHINGTON (AP) — Stepping into his second term, President Barack Obama took the oath of office Sunday in an intimate swearing-in ceremony at the White House, the leader of a nation no longer in the throes of the recession he inherited four years ago but still deeply divided.

The president, surrounded by family in the ornate White House Blue Room, was administered the brief oath of office by Chief Justice John Roberts. With Obama’s hand resting on a Bible used for years by Michelle Obama’s family, the president vowed “to support and defend the Constitution of the United States,” echoing the same words spoken by the 43 men who held the office before him.

About a dozen family members were on hand to witness Obama’s swearing in, including the first lady, daughters Malia and Sasha, the president’s sister Maya Soetoro-Ng and her family. Mrs. Obama’s mother Marian Robinson, and the first lady’s brother, Craig Robinson and his family. A few reporters also were in the room.

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The president will repeat the swearing in ritual again Monday on the west front of the Capitol, before a jubilant crowd of up to 800,000 people.

Sunday’s smaller ceremony was a function of the calendar and the Constitution, which says presidents automatically begin their new terms at noon on Jan. 20. Because that date fell this year on a Sunday — a day on which inaugural ceremonies historically are not held — organizers scheduled a second, public swearing-in for Monday.

The mood in the nation’s capital was more subdued during this year’s inaugural festivities than it was four years ago, when Obama swept into office on a wave of national optimism, becoming the first black man to hold the nation’s highest office. Since then, he has endured fiscal fights with Congress and a bruising re-election campaign — and has the gray hair and lower approval ratings to show for it.