WASHINGTON -- A day after formally beginning his second term, President Barack Obama on Monday takes part in the full trappings of his inauguration by reciting the oath of office in front of a crowd expected to number between 800,00 and 900,000 people.
The nation's first African-American president also will become only the 17th U.S. leader to deliver a second inaugural address before leading the traditional parade up Pennsylvania Avenue to the White House.
Amid the pomp and ceremony, with red, white and blue bunting festooned throughout central Washington, the event symbolizes American democracy with its peaceful extension of power based on last November's election that returned Obama to the White House.
And now Obama begins the second half of his presidency with the opportunity to make it more historic but facing some of the same challenges that he struggled with in the first half.
Satisfying the constitutional obligation to be sworn in on January 20, Obama and Vice President Joe Biden took quiet oaths the day before Monday's public ceremony at the Capitol.
The tone of the inaugural address will be "hopeful," Obama senior adviser David Plouffe told CNN, explaining that the president would "remind the country that our founding principles and values still can guide us in a changing and modern world."
Plouffe said that "the challenges and opportunities are enormous" in the president's second term, and that those challenges would be confronted as soon as the inaugural celebrations play out.
Reality of second-term presidencies
An estimated 1.8 million onlookers jammed the National Mall for Obama's first inauguration. The smaller crowd this time around reflects the reality of second-term presidencies, when the novelty and expectations of a new leader have been replaced with the familiarity and experiences of the first four years.
For Obama, that difference is even sharper. His historic ascendancy to the White House in 2008 came with soaring public hopes and expectations for a new kind of governance that would close the vast partisan gulf developed in recent decades.
However, a litany of challenges including an inherited economic recession and repeated battles with congressional Republicans over budgets and spending only hardened the opposing positions in Washington.
Obama's signature achievements, including major reforms of the health care industry and Wall Street, became symbols of political division, with opponents constantly accusing him of hindering needed economic recovery.
A second-term Obama has vowed to press for an overhaul of the nation's immigration policies and new ways to boost the sputtering economy -- proposals that are bound to spark battles with his Republican rivals -- and oversee the implementation of Obamacare.
And the shootings at a Connecticut elementary school last month put the divisive issue of gun control on his immediate agenda.
CNN polling released Sunday showed a majority of Americans -- 54% -- believe Obama will be an outstanding or above average president in his second term, while 43% said he'd be poor or below average.
And while overall, seven in 10 Americans hope the president's policies succeed, only four in 10 Republicans feel that way, with 52% hoping that Obama will fail.
Obama's swearing-in on Sunday took place in the ornate Blue Room, an oval-shaped reception space in the president's official residence, where he was joined by his wife, Michelle, and his two daughters.
Obama placed his left hand on a Bible held by Mrs. Obama that was from her family. He then raised his right hand.
Chief Justice John Roberts administered the oath - his third time to hold that honor. After Roberts flubbed the order of words during the public ceremony in 2009, a do-over took place in the White House Map Room the next day to erase any question that Obama was officially the president.
Roberts didn't have any trouble with the oath this time around. He read from a white note card. Slash marks where Roberts paused to have Obama repeat the words were clearly visible.
The event took less than a minute and Obama didn't make any formal remarks or statements.
He did take a moment to hug his wife and daughters, exclaiming: "I did it!"
Justice Sonia Sotomayor performed the honors for Biden at his home at the Naval Observatory in Washington, where the vice president's extended family and a few Cabinet officials gathered to watch the ceremony.
Both Obama and Biden went to Arlington National Cemetery after Biden's swearing-in for a traditional wreath laying.
The president and his family also attended services celebrating the Rev. Martin Luther King Jr. at Metropolitan African Methodist Episcopal Church, one of the most historic churches in Washington.
Sunday evening, the Obamas watched Latino acts at "In Performance at the Kennedy Center," which was followed by the "Let Freedom Ring" concert. The "Red, White and Blue Inaugural Ball" and "Hip-Hop Inaugural Ball" closed out Sunday's activities.
Obama also thanked donors at an event at the National Building Museum, telling them, "When we put our shoulder to the wheel of history, it moves forward."
But Obama also told them that his remarks were going to be short, given the speech he would be delivering on Monday, saying, "There are a limited amount of good lines and I don't want to use them all up."
Inauguration activities kicked off on Saturday with Obama and Mrs. Obama and Biden and his wife, Jill, leading volunteers across the country in National Day of Service Activities.
Later Saturday, singer Katy Perry headlined a concert for children of military families and Washington schoolchildren, hosted by Michelle Obama and Jill Biden. Singer Usher and the cast of the TV show "Glee" were among others who performed.
CNN's Tom Cohen, Dana Davidsen, Brianna Keilar, Kevin Liptak, Dan Lothian and Gregory Wallace contributed to this report