WASHINGTON (CNN) -- President Barack Obama launched his second term Monday by calling on the nation to live up to its founding ideals and for Americans to fulfill their citizenship by participating in the process to bring needed change.
In becoming the 17th U.S. president to deliver a second inaugural address, Obama invoked the country's history of facing hardship in citing the chronic federal deficit, rising health care costs, climate change and equal rights as continuing challenges to be faced.
"We are made for this moment, and we will seize it -- so long as we seize it together," Obama said at the U.S. Capitol as flag-waving celebrants thronged the National Mall for the 57th presidential inauguration.
Before the speech, the nation's first African-American president and Vice President Joe Biden took their oaths of office for the second time in two days. Later Monday, Obama will lead the traditional parade up Pennsylvania Avenue to the White House and attend two official inaugural balls.
Amid the pomp and ceremony, with heralding trumpets announcing the arrival of dignitaries and red, white and blue bunting festooned throughout central Washington, the event symbolized American democracy with a peaceful extension of power based on last November's election that returned Obama to the White House.
Americans, Obama said in concluding the roughly 2,000-word address, "have the power to set this country's course." He urged people to fulfill their citizenship by meeting "the obligation to shape the debates of our time -- not only with the votes we cast, but with the voices we lift in defense of our most ancient values and enduring ideals."
While focusing on broader themes of democracy and citizenship, Obama referred to some specific issues facing the country after his first four years in power.
He sounded themes from his re-election campaign last year, saying Americans understand that "our country cannot succeed when a shrinking few do very well and a growing many barely make it."
The nation faces "hard choices" to reduce its chronic federal deficits and the costs of health care," Obama said, "but we reject the belief that America must choose between caring for the generation that built this country and investing in the generation that will build its future."
Unlike the election campaign, Obama made a direct reference to climate change, saying the nation would "respond to the threat ... knowing that the failure to do so would betray our children and future generations."
He made made a reference to gun control in saying that the nation needed to ensure that "all our children, from the streets of Detroit to the hills of Appalachia to the quiet lanes of Newtown, know that they are cared for, and cherished, and always safe from harm."
Obama also said Americans "still believe that enduring security and lasting peace do not require perpetual war," pledging to "show the courage to try and resolve our differences with other nations peacefully -- not because we are naïve about the dangers we face, but because engagement can more durably lift suspicion and fear."
The loudest cheer came when Obama said the nation's journey remained incomplete "until our wives, our mothers, and daughters can earn a living equal to their efforts," and "until our gay brothers and sisters are treated like anyone else under the law."
Monday's ceremony followed a private swearing-in on Sunday at the White House to satisfy the constitutional obligation of taking the oath of office on January 20.
At the public celebration, two former presidents, Cabinet officials, Supreme Court justices, members of Congress and other dignitaries filled the temporary facade on the West Front of the U.S. Capitol.
Not in attendance was Veterans Affairs Secretary Eric Shinseki, the designated "survivor" for the event.
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 four years.
He hosted congressional leaders from both parties for tea on Monday morning, and will take part in a traditional lunch with them after his inauguration speech.
On the Mall, Carlos Arieta and his wife, Sharon, took in the scene after driving from Atlanta to witness history. The former Washington residents said it was their first inauguration in person.
Surprised by the throngs gathered a few hours before the speech on a clear morning with temperatures just above freezing, Arieta said "it's nice to see all the different kinds of people."
A new CNN/ORC International poll released Monday indicated less excitement this time than four years ago, when nearly two million people crowded the Mall despite frigid weather for Obama's historic first inauguration.
In January 2009, nearly seven in 10 Americans questioned in a CNN survey said they were thrilled or happy that Obama was about to take office. Now, according to the new, that number is down 18 points, to 50%.
Back then, six in 10 saw Obama's inauguration as a celebration by all Americans of democracy in action, with just 39% saying it was a political celebration by the supporters of the winning candidate.
Now, the numbers are nearly reversed, with 62% saying the second inauguration is a celebration by those backing the president, and 35% saying it's a celebration of democracy.
"The thrill is gone, along with the hope that the start of a new presidential term of office will bring a divided nation together," said CNN Polling Director Keating Holland.
Reality of second-term presidencies
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 act.
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.
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.
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."
CNN's Tom Cohen, Dana Davidsen, Ashley Killough, Paul Steinhauser, Dana Bash, Jessica Yellin, Dan Lothian, Brianna Keilar, Kevin Liptak and Gregory Wallace contributed to this report.