By SCOTT SHANE

WASHINGTON


THE SPECTER OF terrorism still haunts the United States after 9/11. Agents from the Federal Bureau of Investigation were recently working double time to unravel the alarming case of a Denver airport shuttle driver accused of training with explosives in Pakistan and buying bomb-making chemicals. In Dallas, a young Jordanian was charged with trying to blow up a skyscraper; in Springfield, Illinois, a prison parolee was arrested for trying to attack the local federal building; and a new audiotape, reportedly from Osama bin Laden, warns that anti-American attacks will not stop unless the United States ends the wars in Iraq and Afghanistan. Meanwhile, the Obama administration struggled to decide whether sending many more troops to Afghanistan would be the best way to forestall a future attack.

But important as they were, those news reports masked a surprising and perhaps heartening long-term trend: Many students of terrorism believe that in important ways, Al Qaeda and its ideology of global jihad are in a pronounced decline - with its central leadership thrown off balance as operatives are increasingly picked off by missiles and manhunts and, more important, with its tactics discredited in public opinion across the Muslim world.

“Al Qaeda is losing its moral argument about the killing of innocent civilians,” said Emile A. Nakhleh, who headed the Central Intelligence Agency’s strategic analysis program on political Islam until 2006. “They’re finding it harder to recruit. They’re finding it harder to raise money.”

Marc Sageman, a former C.I.A. officer and forensic psychiatrist, counted 10 serious plots with Western targets, successful and unsuccessful, that could be linked to Al Qaeda or its allies in 2004, a peak he believes was motivated by the American-led invasion of Iraq the year before. In 2008, he said, there were just three.

Dr. Sageman has been in the forefront of those who argue that the centrally led Al Qaeda responsible for the September 11, 2001, attacks is giving way to a generation of dispersed, aspiring terrorists linked largely by the Internet - who still pose a danger, but of a lesser degree.

“I said two years ago it was a diminishing problem, and everything I’ve seen since then has confirmed it,” Dr. Sageman said of what counterterrorism specialists call Al Qaeda Central.

Audrey Kurth Cronin, a professor at the National War College in Washington, cites the arcs of previous violent extremist groups, from the Russian People’s Will to the Irish Republican Army, that she studied for her new book, “How Terrorism Ends.”

“I think Al Qaeda is in the process of imploding,” she said. “This is not necessarily the end. But the trends are in a good direction.”

Yet the question of how much comfort to take from such an assessment, and whether it should change American counterterrorism policy, remains unanswered. Even counterterrorism officials who agree that Al Qaeda is on the wane, for example, say the organization might well regroup if left unmolested in a lawless region in Pakistan, Afghanistan or Somalia. They point out that even a lone terrorist with modest skills can produce mass carnage.

Nevertheless, some government officials do take quiet, if wary, satisfaction in two developments that they say underlie the broad belief that Al Qaeda is on a downhill slope. One is the success of military Special Operations units, the C.I.A. and allies in killing prominent terrorists.

Three days apart in mid-September, American special forces in Somalia firing from helicopters killed Saleh Ali Saleh Nabhan, a leader of a Somalian organization, Al Shabab, which is allied with Al Qaeda, and the police in Indonesia killed the mostwanted terrorist in Southeast Asia, Noordin Muhammad Top, in an assault on a house in Java.

In Pakistan, missile strikes from C.I.A. drone aircraft have taken a steady toll on Al Qaeda and its Taliban allies since the Bush administration accelerated these attacks last year, a policy reinforced by President Obama.

The constant threat of attack from the air also makes it far harder for terrorists to move, communicate, and plan, counterterrorism officials say.

The second trend is older and probably more critical. The celebration in many Muslim countries that followed the September 11, 2001, attacks has given way to broad disillusionment with mass killing and the ideology behind it, according to a number of polls.

Between 2002 and 2009, the view that suicide bombings are “often or sometimes justified” has declined, according to the Pew Global Attitudes Project, from 43 percent to 12 percent in Jordan; from 26 percent to 13 percent in Indonesia; and from 33 percent to 5 percent in Pakistan. Positive ratings for Osama bin Laden have fallen by half or more in most of the countries Pew polled.

Peter Mandaville, a professor of government and Islamic studies at George Mason University in Virginia, says a series of public recantations by prominent Islamist scholars and militants in recent years have had an effect. But the biggest catalyst has been bombings close to home.

“Right after 9/11, people thought, wow, America is not invincible,” Mr. Mandaville said. “It was a strike against the U.S., and they were for it.” But when large numbers of innocent Muslims fell victim to attacks, “it became more and more difficult to romanticize Al Qaeda as fighting the global hegemons.”

In addition, Al Qaeda offered no practical solutions for local problems: unemployment, poverty, official corruption and poor education.

Even those who are convinced Al Qaeda is growing weaker offer a cautious prognosis about what that might mean. They say that what is growing less likely is an attack on American soil with a toll equal to or greater than that of 9/11. But they concede that the example of Al Qaeda will continue to produce copycats: “Bin Laden has given others a narrative, a grand story of struggle, and he’s given them tactics as well,” Dr. Mandaville said.

Dr. Sageman said the United States should approach the threat not with hysteria, but with a careful analysis of the motives and patterns of people drawn into violent plotting.

“Terrorism,” he added, “is here to stay.”


Many students of terrorism believe that the killings of civilians in bombings has alienated many Muslims. London commuters looked at the scene of a bus explosion in 2005.