In New York City, at the site where the two iconic towers of the World Trade Center had fallen, a youth choir sang the national anthem before Mayor Michael Bloomberg told the crowd that the day marks the seventh anniversary of "the day our world was broken."
"It lives forever in our hearts and in our history, a tragedy that unites us in a common memory and a common story," Bloomberg said. "We return this morning as New Yorkers, Americans, and global citizens, remembering the innocent people from 95 nations and territories that lost their lives together that day."
At 8:46 a.m. local time -- the moment when the first of two planes hit the World Trade Center -- Bloomberg called for a moment of silence that began with the sound of a firehouse bell.
Then the names of the New York victims were read out. Citizens -- some relatives of the victims, some friends, some just ordinary New Yorkers -- read the list of 2,751 names.
Washington And Pennsylvania
In Washington, President George W. Bush and Vice President Dick Cheney, joined by their wives and hundreds of maintenance workers at the presidential mansion, military personnel, and diplomats and Congressional leaders, observed a moment of silence at the White House.
Bush and Cheney then went to the Pentagon for the dedication of a memorial park to the 184 people -- some passengers, some working at their desks -- who were killed when a third jetliner rammed into the Defense Department headquarters.
Among the speakers at the Pentagon event was Donald Rumsfeld, who was secretary of Defense seven years ago and was in the Pentagon at the time of that attack. He said the memorial would remind those who visit of how the United States began what Bush calls the "war on terror."
Bush then spoke of the two wars that have followed the 9/11 attacks -- in Afghanistan and in Iraq -- and of the effort that the United States has put into them.
"Since 9/11, our troops have taken the fight to the terrorists abroad so we do not have to face them here at home," Bush said. "Thanks to the brave men and women and all those who work to keep us safe, there has not been another attack on our soil in 2,557 days."
There was a simpler observance of the anniversary in rural Shanksville, Pennsylvania, where a fourth plane, carrying 40 people, crashed in a field. That plane is thought to have been headed toward the White House before passengers on board wrestled control from the crew of hijackers. The name of each victim was read out, to the peal of a bell, as mourners laid wreaths at a temporary memorial. A permanent monument is being built.
With a presidential election less than two months away, both candidates, Democrat Barack Obama and Republican John McCain, were also attending events to mark the anniversary. Both visited Ground Zero, the former site of the World Trade Center's twin towers, and later addressed an event called the ServiceNation Summit at Columbia University in New York, calling attention to the importance of national service.
"I think the best way to commemorate and the best way to show our appreciation, and love, and sympathy for their families, for those who have sacrificed, is to serve our country," McCain told the summit audience. "That's what this forum is all about, serving our country, and that way we can assure their families it will never happen again. That way we can honor their service and their sacrifice to our nation."
Although both campaigns had pledged to put aside the partisan bickering of the current campaign for the presidency, Obama in his summit appearance challenged what he suggested was a regrettable legacy of the Bush administration.
"The question is, how do we recreate that spirit, not just during times of tragedy, not just during 9/11, but how do we honor those who died, those who sacrificed, the firefighters, the police officers, how do we honor them every day?" Obama asked. "How does it reflect itself in our government, how does it reflect itself in how we conduct our own civic life? And my sense is that the country yearns for that, it's hungry for it. And what has been missing is a president, and a White House, that taps into that yearning."
The events of 9/11 have had a powerful impact on the U.S. views of the country's role in world politics, prompting some to reconsider the direction of U.S. foreign policy and others to stand even more firmly on the economic and political principles of the past 50 years.
It wouldn't be an overstatement to say these events have defined Bush's presidency, according to two political observers interviewed by RFE/RL. In fact, they said, 9/11 and the subsequent Iraq war were at one time considered the leading issues of this year's presidential campaign.
But as the mortgage-lending crisis has grown, U.S. political candidates have increasingly focused their attention on the economy -- both America's and the world's.
Robert Spitzer, professor of political science at the State University of New York at Cortland, says 9/11 and the Iraq war have become secondary to the economy in the presidential campaign. The issue of national security -- embodied in the Iraq war -- looms less large to Americans because of the recent surge in U.S. troop levels ordered by Bush.
"[The Iraq war] is still an issue, but in terms of [U.S.] domestic politics, economic troubles have eclipsed it," Spitzer says. "The price of gas, an economy that's sputtering along -- it may not be in a recession, but it seems like a recession to many people. So economic issues [are] number one, and Iraq has ben bumped further down the list."
That view is not universal.
Patrick Basham, the founding director of the Democracy Institute, a Washington think tank, acknowledges that his view may put him in the minority of political analysts, but he believes national security and the economy are equally important to American voters.
"The irony is that Iraq has come back into the political equation, but it's no longer all negative -- or, should I say, the Republicans and John McCain have done a pretty good job of putting a very good, positive spin on those aspects of the war in Iraq that have improved," Basham says. "They, of course, have had to grab hold of something positive that they could campaign on. It's a wonderful illustration of how the country is split."
But both Spitzer and Basham agree that 9/11 defined the Bush presidency.
Spitzer notes that when Bush became president -- after a much-disputed ballot-counting process that was resolved not by voters but by the U.S. Supreme Court, Bush had low approval ratings in virtually all polls. But just after 9/11, Bush's ratings soared because of what was seen as the decisive response he mounted.
"By accident or by design, the Bush presidency found its raison d'etre with what it determined to be a necessary war on terror, and I think very successfully -- very skillfully in a political sense -- choreographed Bush's first term around that, and got a lot more political mileage out of Bush's first term than would otherwise have been the case," Basham says.
By contrast, he adds, Bush's second term was hobbled by his administration's poor performance in helping the people of New Orleans after the city was ravaged by Hurricane Katrina in the late summer of 2005, the managing of the Iraq war, and, more recently, the sluggish U.S. economy.
But will 9/11 maintain its hold on American politics after Bush is gone and either McCain or Obama takes over in January? Will they define the next president's administration?
Spitzer says he doesn't think so but predicts it will be "a vital element of those presidencies."
"If, for example, there is a new terrorist attack -- that will certainly have a galvanizing effect on that president," Spitzer says. "Even if there is not, the global war on terror continues. It's becoming a bigger and bigger concern in Afghanistan, where America is now sending more troops, and I think it's clear that both [McCain and Obama] have indicated that they believe that more American troops need to be sent -- and perhaps troops from other nations as well -- need to be sent to Afghanistan."
But Basham says it's most likely that if McCain succeeds Bush, his presidency, too, would be defined by the "war on terror."
"I say 'most likely' because McCain is unlikely to change strategy in any kind of dramatic way, and therefore there will be more of the same approach [as Bush's] in Iraq, probably not a tremendously different approach to Afghanistan, and the general approach to counterterrorism will be along similar lines," Basham says. "I mean, there'll be some tactical changes, and, I suspect, probably from a political point of view, some more astute moves [than Bush's] that will placate some of the opposition."
From RFE/RL's Archives
Coverage in the immediate aftermath of the attacks:
Afghanistan's Neighbors Face New Concerns
What Is The U.S. Looking For From Pakistan?
Experts Say Danger Lies In Irresponsible Response To Terror Attacks
Analysts Say Military Occupation Not An Option In Terror War
Advocates Warn Of Possible Erosion Of Liberties
Terrorist Network 'Must Be Beaten At Its Own Game'
Central Asia: The Give And Take Of A War Against Terror
Iran Opts For Active Opposition To War On Terrorism Led By U.S.