It's been more than six years since the al-Qaida network was routed from its bases in Afghanistan.
In the meantime, many al-Qaida leaders have been killed or captured — but not Osama bin Laden or his deputy, Ayman al-Zawahiri.
Within intelligence circles, there is debate over whether the terrorist network has recovered from the setbacks it suffered after the Sept. 11, 2001, attacks. Some analysts say al-Qaida is a shell of what it once was. But U.S. intelligence officials are not so sure.
There are many different judgments of al-Qaida's strength being put forth these days. Just last month, President Bush, before the Conservative Political Action Conference, said the group is reeling.
"The Taliban, al-Qaida and their allies are on the run," Bush said.
But the president's own intelligence agencies offer a different opinion.
National Intelligence Director Michael McConnell, in his most recent threat assessment, said the core al-Qaida leadership has "regenerated."
Having survived the global war on terror, al-Qaida in this view is again a centrally directed network with military capabilities. Speaking on CNN two weeks ago, McConnell reflected that view.
"They have the leadership that they had before, they've rebuilt the middle management, the trainers," McConnell said. "And they're recruiting very vigorously."
U.S. analysts say the key development in the al-Qaida comeback was a September 2006 cease-fire agreement in Pakistan between the government and Islamic militants in the area along the border with Afghanistan.
With Pakistani security forces staying out of the region, al-Qaida militants were able to re-establish themselves in that area.
"I think that safe haven has made al-Qaida stronger today than it was two years ago," said Michael Leiter, acting director of the National Counterterrorism Center.
"That has allowed it to recruit, train, and deploy individuals in plots against Western Europe and potentially the homeland" — or, the United States, he said.
Before 2006, al-Qaida was arguably on the run, under attack, its mid-level leadership decimated. Osama bin Laden and his associates were still able to inspire Islamic militant groups in Africa and the Middle East — but they could not direct them.
Army Maj. Reid Sawyer, of West Point's Combating Terrorism Center, says that is now changing — and that al-Qaida's central leadership, securely based in Pakistan, is once again taking charge.
"What we have been observing is al-Qaida's attempt to re-assert control throughout their disparate networks, with al-Qaida in the Arabian Peninsula, in the Horn of Africa, to provide guidance and mentoring, if you will, as well as some funding to these organizations," Sawyer said.
"And so the organization has coalesced again, because of its ability to have sanctuary. And that's really given it such a benefit that can't be overstated."
Michael Scheuer, a top al-Qaida specialist at the CIA until 2004, goes even further in his assessment.
"I think al-Qaida as an organization was never seriously damaged," Scheuer said. "What we're seeing is, it has a new base. It is fairly comfortable where it sits at the moment. And it is able to go back to doing the things it did since 1988."
But the world has changed since 1988 — and so has al-Qaida.
The group is now on the Internet, and it even has its own media company, producing videos for radical Islamist Web sites.
With these new tools, the Internet makes it possible for al-Qaida to promote its vision of jihad or holy war and solicit recruits throughout the Muslim world.
Sawyer says the Internet even provides a training mechanism, taking the burden off al-Qaida bases in Pakistan.
"What the Internet has really created for al-Qaida and its affiliated groups is a virtual sanctuary, this ability for individuals to meet online, to discuss, think about operations in a strategic sense — and then for, in essence, distance-learning to occur," Sawyer said, "where videos can be uploaded, instructional videos, and then any individual can come along and download that information and conduct operations with it."
One of the things this means, however, is that "jihadis" ready to engage in terrorism may no longer need al-Qaida Central. In recent years, many homegrown terrorist groups have sprung up.
Marc Sageman, a former CIA agent and forensic psychiatrist, has closely tracked the evolution of the jihadi movement. He thinks most of the terrorism conducted these days has little to do with the senior al-Qaida leadership.
"What we have here is a variety of local movements, people who hang out together, who decide to do something, and we lump them with al-Qaida and, indeed, raise their status," Sageman said. "Whereas, we should treat them as local common criminals, not really make heroes out of them for young people to emulate."
Sageman does not dispute that the al-Qaida leadership has been able to re-settle in the Pakistani border area and even re-establish some training camps there. But he says this new al-Qaida sanctuary is nothing like what it had in Afghanistan before the Sept. 11, 2001, attacks.
"Now what people call a training camp is really a rented house for about a month, that has maybe half a dozen people," Sageman said.
With his new book, Leaderless Jihad, Sageman has become a key figure in the debate over whether the al-Qaida organization is a growing threat. He argues that the old al-Qaida of Osama bin Laden is now less important, with homegrown groups becoming the new face of global terrorism. It's largely an optimistic view — small, local, terrorist groups are less likely to assemble a nuclear weapon or carry out large, complex plots like the Sept. 11 attacks.
Moreover, Sageman argues that the old al-Qaida vision of holy war leading to the establishment of a new Islamic caliphate hasn't proved very successful in practice.
"Al-Qaida is strong as long as it's a fantasy," Sageman said. "In the three instances where al-Qaeda-like movements took control of territories — namely Afghanistan under the Taliban, some parts of Algeria during the civil war in the '90s, and Al Anbar province in Iraq — the reality never lived up to those fantasies. And therefore people after a while became disillusioned — and then strongly disillusioned, to the point where they turned against the al-Qaida and al-Qaida-like movements."
Of these three cases, the clearest is the experience of the so-called "Al-Qaida in Iraq" organization, largely led by foreigners. Many Iraqi Sunnis have rejected the group's violent ways — especially its willingness to attack other Muslims.
In Pakistan, radical Islamist parties identified with al-Qaida suffered big setbacks in recent elections.
But Al-Qaida in Iraq was always something of a maverick group, and the election results in Pakistan may have had more to do with local factors than with an ideological rejection of the al-Qaida message.
Scheuer, whose new book is titled Marching Toward Hell, says that it's a mistake to conclude from recent developments that al-Qaida is on its way out.
"We're very quick to ascribe defeat to the enemy when they don't have a success when we expect them to have a success," Scheuer said.
"We tend to think if we're not attacked when we expected an attack, that we won — or the enemy is not capable of doing it. And in many times, it's just an issue of patience."
Al-Qaida may in fact be weaker and less dangerous than it seemed a few years ago. Or it could just be evolving, and possibly growing stronger. One lesson to be learned from previous intelligence judgments about the terrorism threat is that such estimates can be wrong.