When President Obama walked down the red-carpeted corridor to the White House East Room on Sunday night -- to announce the killing of al-Qaida leader Osama bin Laden -- he did so against the backdrop of thousands of people celebrating the news just outside, waving American flags and jubilantly singing "The Star-Spangled Banner." He was expected to address the nation at 10:30, but his remarks didn't come until an hour later, presumably to assure hitting the right tone.

In a nine-minute speech, his message was at once powerful and sensitive. Resisting the inclination to strut and take on excessive cowboy bravado, he tempered the celebration by maintaining that, even with bin Laden's death, things are still complicated.

The president thanked the "tireless and heroic work" of the military and counterterrorism professionals over the past 10 years, stressing that the pursuit of bin Laden has been a lengthy bipartisan exercise. He also explained that, after receiving intelligence last August on bin Laden's location at a large compound in Pakistan, he directed an operation which was carried out on Sunday.

In a background press briefing after the president's speech, senior administration officials detailed the helicopter raid by U.S. forces against bin Laden's compound in an affluent suburb of Islamabad. The small U.S. team was on the compound for less than 40 minutes before shooting bin Laden in the head during a firefight. Three other adult males, believed to be couriers and one of bin Laden's adult sons, were also killed, along with one woman who was used as a human shield by a combatant. Two other women were injured.

Obama emphasized that bin Laden's death does not mark the end of military efforts in the Middle East and the counterterrorism mission. "There's no doubt that al-Qaida will continue to pursue attacks against us," he said. "We must, and we will, remain vigilant at home and abroad."

He also reaffirmed that "the United States is not, and will never be, at war with Islam," pointing out that bin Laden was behind mass murders of Muslims in Egypt, Kenya, Tanzania, Indonesia, Iraq, Jordan and other countries. He further acknowledged the irreparable losses of American families whose loved ones died in the Sept. 11 attacks and while serving in the ensuing wars.

"Americans understand the costs of war," he said. "Yet as a country, we will never tolerate our security being threatened, nor stand idly by when our people have been killed. … And on nights like this one, we can say to those families who have lost loved ones to al-Qaida's terror: Justice has been done."

According to news reports, hours after President Obama's announcement, bin Laden's body was buried at sea.

In the post-speech briefing, an administration official upheld the death of bin Laden as "the single greatest victory in the U.S.-led campaign to disrupt, dismantle and defeat al-Qaida." He explained that with bin Laden having served as the militant group's only leader with broadly respected authority, and charisma that attracted followers, his successor will likely have problems maintaining loyalty and cohesion.

Still, officials also struck down any suggestion that bin Laden's death ensures anyone's safety. In fact, there may well be a heightened threat if al-Qaida operatives and sympathizers violently attempt revenge. On Monday, the State Department likewise warned of "enanced potential for American violence" following bin Laden's death. "The United States is taking every possible precaution to protect Americans here at home and overseas," one official said. "The United States will continue to fight [terrorist] threats. We have always understood that this fight would be a marathon and not a sprint."

Congressional Black Caucus Chairman Emanuel Cleaver issued a statement saying, "Although we recognize this victory as a new day in our in our nation's efforts against global terrorism, we do recognize that the threat of terrorism still exists and we must remain vigilant."

The immediate aftermath has seen a range of strikingly different and strong reactions, from expressions of pride and patriotism to disgust and horror at people rejoicing in the death of anyone. There has also been the almost amusing failure of some Republicans to even mention President Obama's name in their statements praising the operation, apparently attempting to avoid giving him credit. (When he said last week that we had more serious things to deal with than his birth certificate, I would remind them, he wasn't joking). I'm in perhaps in the larger camp of mixed emotions, feeling a sense of relief -- and, yes, justice -- in bin Laden's death while also grasping that it doesn't make the world any less complex. How are you feeling about the news?