By Jeff Mason

(Reuters) - U.S. President Barack Obama will take the oath of office for the third, fourth and final time this weekend during an inauguration celebration that kicks off his second term in a more muted tone than his historic swearing-in four years ago.

Preparations continue on the U.S. Capitol for the second inauguration of US President Barack Obama in Washington, DC, on January 17, 2013.  (Jewel Samad/AFP/Getty Images)

High unemployment and partisan fights over fiscal policies have drained some of the hope that marked Obama's first swearing-in after he swept to victory on a mantle of change in 2008 to become America's first black president.

This time around, there is a less festive inauguration.

On Sunday, following a wreath-laying ceremony at Arlington National Cemetery, Obama will be sworn in officially at the White House at 11:55 a.m. EST (1655 GMT), meeting the constitutional requirement that he do so on Jan. 20. That portion will be private - except for a media presence - with a small audience of mostly family members.

Obama repeats the procedure on Monday during a public ceremony at the U.S. Capitol.

Both times he will be sworn in by Supreme Court Justice John Roberts who, in 2009 after flubbing the oath the first time, administered it to Obama again in the White House the day after his inauguration. The president's two recitations this year will be the third and fourth time he has taken the oath.

It will be only the second time he has made an inaugural address, however, and millions worldwide will be watching. Some 800,000 people are expected to flock to Washington for the event, down from a record 1.8 million in 2009.

What Obama is expected to talk about;