WASHINGTON - Turning the page on years of war and recession, President Obama summoned a divided nation Monday to act with "passion and dedication" to broaden equality and prosperity at home, nurture democracy around the world and combat global warming as he embarked on a second term before a vast and cheering crowd that spilled down the historic National Mall.
"America's possibilities are limitless, for we possess all the qualities that this world without boundaries demands," the 44th president declared in a second inaugural address that broke new ground by assigning gay rights a prominent place in the wider struggle for equality for all.
In a unity plea to politicians and the nation at large, he called for "collective action" to confront challenges and said, "Progress does not compel us to settle centuries-long debates about the role of government for all time - but it does require us to act in our time."
The weather was relatively warm, in the mid-40s, and while the crowd was not as large as on Inauguration Day four years ago, it was estimated at up to 1 million.
Big enough that he turned around as he was leaving the inaugural stands to savor the view one final time.
"I'm not going to see this again," said the man whose political career has been meteoric - from the Illinois Legislature to the U.S. Senate and the White House before marking his 48th birthday.
The inauguration this year shared the day with Martin Luther King Jr.'s birthday holiday, and the president used a Bible that had belonged to the civil-rights leader for the swearing-in, along with a second one that been Abraham Lincoln's. The president also paused inside the Capitol Rotunda to gaze at a dark bronze statue of King.
Obama addressed cheering crowds at the Commander in Chief Ball, speaking by video to thank a group of troops in southern Afghanistan. Then he introduced his "date," Michelle Obama, who danced with her husband in a ruby chiffon and velvet gown while Jennifer Hudson sang "Let's Stay Together."
In his brief, 18-minute speech, Obama did not dwell on the most pressing challenges of the past four years. He barely mentioned the struggle to reduce the federal deficit, a fight that has occupied much of his and Congress' time and promises the same in months to come.
He spoke up for the poor - "Our country cannot succeed when a shrinking few do very well and a growing many barely make it" - and for those on the next-higher rung - "We believe that America's prosperity must rest upon the broad shoulders of a rising middle class." The second reference echoed his calls from the presidential campaign that catapulted him to re-election
"A decade of war is now ending. An economic recovery has begun," said the president who presided over the end to the U.S. combat role in Iraq, set a timetable for doing the same in Afghanistan and took office when the worst recession in decades was still deepening.
In a jab at climate-change doubters, he said, "Some may still deny the overwhelming judgment of science, but none can avoid the devastating impact of raging fires and crippling drought and more powerful storms." He said America must lead in the transition to sustainable energy resources.
He likened the struggle for gay rights to earlier crusades for women's suffrage and racial equality.
"Our journey is not complete until our gay brothers and sisters are treated like anyone else under the law - for if we are truly created equal, then surely the love we commit to one another must be equal as well," said the president, who waited until his campaign for re-election last year to announce his support for gay marriage.
His speech hinted only barely at issues likely to spark opposition from Republicans who hold power in the House.
He defended Medicare, Medicaid and Social Security as programs that "do not make us a nation of takers; they free us to take the risks that made this country great."
He referred briefly to making "the hard choices to reduce the cost of health care and the size of our deficit," a rhetorical bow to a looming debate in which Republicans are seeking spending cuts in health-care programs to slow the rise in a $16.4 trillion national debt.