Nine years after the Sept. 11 attacks, memories of the day that would shape much of the next decade are still very much alive.
But just how much of an imprint has 9/11 left on the U.S. psyche? Does the issue continue to impact U.S.-Arab world relations? Will the threat of terror continue to guide U.S. foreign policy? Are there other foreign policy issues of equal or greater importance?
Still fresh in americans' minds
While terrorism is not as emotional an issue now as it was in the first months and years after the attacks on New York and Washington, it is still a major concern among Americans, said Steven Kull, director of the Program on International Policy Attitudes at the University of Maryland.
The U.S. wars in Iraq and Afghanistan, as well as U.S. efforts to thwart attacks, have kept the issue of militancy squarely in the public eye, he said.
Recent controversy surrounding a Muslim organization's plan to build a community center just blocks away from ground zero illustrates Americans' sensitivity regarding the issue. While no one is contesting the group's legal right to build there, many Americans feel that undertaking the project would be insensitive. Many Muslims, in turn, feel the issue amounts to anti-Muslim discrimination.
A continuing threat
Terrorism has been a major focus of Washington for nearly a decade, and that is likely to continue for years to come, although the United States will also have other foreign policy concerns, experts said.
"The central lesson immediately was that the two oceans that have for so long protected the United States from foreign attack were no longer a barrier," said Kyle Spector, policy advisor for national security at Third Way.
"Individuals with enough money and ideology could attack if they wanted," he said.
That would change over the course of the decade, however, as U.S. and international pressure have put severe restrictions on Al Qaida's ability to raise cash and placed limitations on its ease of movement.
Still, terrorists have discovered other methods of recruitment - some individuals living in the United States have become radicalized via extremist Web sites and have planned or attempted attacks within U.S. borders.
But many experts said extremists' ability to launch large scale attacks such as the ones on the World Trade Center has significantly diminished and what the United States is more likely to see are smaller scale attacks.
Last year's shootings in Fort Hood, Texas, when a U.S. Army psychiatrist allegedly went on a shooting rampage and killed 13 U.S. soldiers in November, serve as a prime example. The shooter, Nidal Malik Hasan, allegedly has ties to Al Qaida's Yemeni branch.
Such operations are easier to plan and execute than the Sept. 11 attacks on New York and Washington and can be used effectively to spread propaganda, analysts said.
A pistol or simple attack on a shopping mall would be a PR win for many terror groups. Not only would it strike fear into the hearts of Americans, it would also demonstrate an organization's ability to strike the heart of the United States, some analysts said.
It would also help their recruiting efforts, as many impressionable individuals in both the Muslim and Western world could find such violence appealing, some experts said.