"We see the threat of its ideology to places where hitherto it really was not terribly strong or salient and we see almost a revival of its brand," says Hoffman. He adds that Islamic terrorists continue to cite al Qaeda as an influence and "aspire to emulate al Qaeda's ideology" of a violent struggle against the United States.
"I think the challenge of al Qaeda remains," says Hoffman. "We may want to wish it away, and we may want to believe that killing bin Laden killed off the brand, or killed off the ideology, but we don't see any evidence of that."
Brian Jenkins, with the Rand Corporation, agrees that bin Laden's death had "an immediate impact" on the group's morale and believes it became even more decentralized and dependent on its allies and affiliates since his death which could erode the group's ideological focus of a violent struggle against the United States.
"One of the things bin Laden did by his very existence was maintain a unanimity of focus, a degree of unity, a single-minded focus on its ideology," says Jenkins. While bin Laden's successor, Ayman al Zawahiri, has struggled to maintain that ideological focus Jenkins believes it could continue to erode and al Qaeda could fragment into many localized movements.
Jenkins is concerned that an "opportunistic" al Qaeda could be resurgent in Syria and Afghanistan. In Syria, Islamic extremists are playing a growing role in the fight to topple President Bashar al Assad leading to concerns about what a post-Assad Syria might look like. In Afghanistan, Jenkins is concerned that al Qaeda could once again find a safe haven in that country should the Taliban expand its control after U.S. combat forces pull out by the end of 2014.
"We have to presume this sort of thing will go on," said Jenkins. "All of these are opportunities for al Qaeda. It's not the same al Qaeda it was on Sept. 11. It's very different and it's still there, and I for one wouldn't exaggerate its death, but I'm not writing its epitaph right now."
Another possible indicator of al Qaeda's diminishing role is the decrease in the number of the CIA's drone strokes in Pakistan this year. Hoffman speculates the decrease could be the result of fewer al Qaeda targets or because "we don't have the intelligence to identify emergent al Qaeda leaders and single them out." He also thinks it might be possible that al Qaeda has gone underground in Pakistan's large cities.
Though credited with reducing core al Qaeda's operational capability, even some of the drone strike program's supporters are now expressing concern that it may be creating longer lasting negative effects that could undermine long term efforts to combat extremism.
"We're seeing that blowback," Gen. James Cartwright, the former vice chairman of the Joint Chiefs of Staff, said in March at the Chicago Council on Global Affairs. "If you're trying to kill your way to a solution, no matter how precise you are, you're going to upset people even if they're not targeted."
Last month, Cartwright said at the first ever Congressional hearing on the drone program that the U.S. risked losing "the moral high ground" if it did not reveal additional details about the program's legal basis and oversight.