Updated 1:44 p.m. ET
President Barack Obama entered the pantheon of Nobel Peace Prize winners Thursday with humble words, acknowledging his own few accomplishments while delivering a robust defense of war and promising to use the prestigious award to "reach for the world that ought to be."
A wartime president honored for peace, Mr. Obama became the first sitting U.S. president in 90 years and the third ever to win the prize - some say prematurely. In this damp, chilly Nordic capital to pick it up, he and his wife, Michelle, whirled through a day filled with Nobel pomp and ceremony.
And yet Mr. Obama was staying here only about 24 hours and skipping the traditional second day of festivities. This miffed some in Norway but reflects a White House that sees little value in extra pictures of the president, his poll numbers dropping at home, taking an overseas victory lap while thousands of U.S. troops prepare to go off to war and millions of Americans remain jobless.
Just nine days after ordering 30,000 more U.S. troops into battle in Afghanistan, Mr. Obama delivered a Nobel acceptance speech that he saw as a treatise on war's use and prevention. He crafted much of the address himself and the scholarly remarks - at about 4,000 words - were nearly twice as long as his inaugural address.
In them, Mr. Obama refused to renounce war for his nation or under his leadership, saying defiantly that "I face the world as it is" and that he is obliged to protect and defend the United States.
At times, he seemed to be channeling his predecessor, George W. Bush, CBSNews.com's Brian Montopoli writes in an analysis.
"A nonviolent movement could not have halted Hitler's armies. Negotiations cannot convince al Qaeda's leaders to lay down their arms," Obama said. "To say that force is sometimes necessary is not a call to cynicism, it is a recognition of history." (Read the full text of Obama's remarks here.)
The president laid out the circumstances where war is justified -- in self-defense, to come to the aid of an invaded nation and on humanitarian grounds, such as when civilians are slaughtered by their own government or a civil war threatens to engulf an entire region.
"The belief that peace is desirable is rarely enough to achieve it," he said.
He also spoke bluntly of the cost of war, saying of the Afghanistan buildup he just ordered that "some will kill, some will be killed."
"No matter how justified, war promises human tragedy," he said.
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Full Text of Obama's Remarks
Video: Obama's Nobel Prize Speech (excerpts)
Analysis: Can Obama Deliver on Nobel Peace Prize Goals?
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But he also stressed the need to fight war according to "rules of conduct" that reject torture and other methods. And he emphasized the need to exhaust alternatives to violence, using diplomatic outreach and sanctions with teeth to confront nations such as Iran or North Korea that defy international demands to halt their nuclear programs or those such as Sudan, Congo or Burma that brutalize their citizens.
"Where force is necessary, we have a moral and strategic interest in binding ourselves to certain rules of conduct," he said. "And even as we confront a vicious adversary that abides by no rules, I believe that the United States of America must remain a standard bearer in the conduct of war."
He added: "That is what makes us different from those whom we fight. That is a source of our strength. That is why I prohibited torture. That is why I ordered the prison at Guantanamo Bay closed. And that is why I have reaffirmed America's commitment to abide by the Geneva Conventions. We lose ourselves when we compromise the very ideals that we fight to defend. And we honor those ideals by upholding them not just when it is easy, but when it is hard. "
"Let us reach for the world that ought to be," Mr. Obama said. "We can understand that there will be war, and still strive for peace."
In awarding the prize to Mr. Obama, the Nobel panel cited his call for a world free of nuclear weapons, for a more engaged U.S. role in combating global warming, for his support of the United Nations and multilateral diplomacy and for broadly capturing the attention of the world and giving its people "hope."
But the Nobel committee made its announcement in October when he wasn't even nine months on the job, recognizing his aspirations more than his achievements.
Echoing the surprise that seemed the most common reaction to his win, Mr. Obama started his 36-minute speech by saying that others who have done more and suffered more may better deserve the honor.
"I am at the beginning, and not the end, of my labors on the world stage," the president said. "Compared to some of the giants of history who have received this prize ... my accomplishments are slight."
The list of Nobel peace laureates over the last 100 years includes transformative figures and giants of the world stage. They include heroes of the president, such as the Rev. Martin Luther King Jr., Nelson Mandela and others he has long admired, like George Marshall, who launched a postwar recovery plan for Europe.
"The international community has toned down its initial surprise at the Nobel prize awarded to President Obama and he remains widely popular among foreign diplomats in the U.S. and overseas," said CBS News Foreign Affairs Analyst Pamela Falk, from the U.N., "but there are concerns, about Afghanistan, about the Middle East, about Iran, and about the passed deadline on strategic arms reduction."
Earlier, Mr. Obama had said that the criticism might recede if he advances some of his goals. But, he added, proving doubters wrong is "not really my concern."
"If I'm not successful, then all the praise in the world won't disguise that fact," he said.
The timing of the award ceremonies, coming so soon after Mr. Obama's Afghanistan announcement, lent inspiration to peace activists.
The president's motorcade arrived at Oslo's high-rise government complex for Obama's meeting with Norwegian Prime Minister Jens Stoltenberg as a few dozen anti-war protesters gathered behind wire fences nearby. Dressed in black hoods and waving banners, the demonstrators banged drums and chanted anti-war slogans. "The Afghan people are paying the price," some shouted.
Greenpeace and anti-war activists planned larger demonstrations later that were expected to draw several thousand people. Protesters have plastered posters around the city, featuring an Mr. Obama campaign poster altered with skepticism to say, "Change?"
CBS News chief White House correspondent Chip Reid, traveling with the president, reports that it's still unclear whether becoming a Nobel laureate will help Mr. Obama or hurt him at home.
Debate over that continued in Norway, where he spent much of a brief pre-ceremony news conference explaining his decision, reports Reid. Mr. Obama said the July 2011 date he set for the U.S. withdrawal from Afghanistan to begin- but that the pace of the full withdrawal will be gradual and condition-based.
"We're not going to see some sharp cliff, some precipitous drawdown," Mr. Obama said.
Mr. Obama's first stop in Oslo was the Norwegian Nobel Institute, where the Nobel committee meets to make its decisions. After signing the guest book, Mr. Obama told reporters he had penned thanks to the committee and noted the pictures of former winners filling the wall, many of whom gave "voice to the voiceless."
In the evening, Mr. Obama is expected to wave to a torchlight procession from his hotel balcony and stroll with Norwegian royalty to a dinner banquet. He will offer comments a second time there and cap his brisk jaunt to Europe.
The president and his wife, Michelle, arrived here in the morning, coming off Air Force One holding hands and smiling. Having left Washington Wednesday night, Mr. Obama was due back by midday Friday.
The Nobel honor comes with a $1.4 million prize. The White House says Mr. Obama will give that to charities but has not yet decided which ones.