LONDON (Reuters) - Their place in history assured, are al Qaeda's ageing leaders content merely to propagate their ideology and tactics among like-minded militant groups?
Counter-terrorism analysts say the answer is no: evidence emerging in the West shows the veteran Islamist instigators of the Sept. 11, 2001 attacks on the United States retain an ambition to execute plots and not just act as propagandists.
They point to investigations into suspected conspiracies uncovered in the past 18 months in the United States, Norway and Britain, which law enforcement officials say were directed by a group of operatives in the core leadership's bases in Pakistan.
Gauging the influence and expertise of the movement's leaders, believed hiding in northwest Pakistan near the Afghan border, is important for Western strategists since Washington has said its main goal in the Afghan war is fighting al Qaeda.
In recent years the threat of U.S. drone strikes is believed to have constrained the ability of a once-active core of plotters around Osama bin Laden and his deputy Ayman al-Zawahiri to bring to fruition significant conspiracies beyond south Asia.
But experts say that in 2008 Saleh al-Somali, then al Qaeda external operations chief and believed close to the leadership, set in motion a plot in the United States and two alleged conspiracies uncovered in Britain and Norway.
He organised bomb-training for militants in northwest Pakistan and sent them back to prepare attacks in the United States, Britain and Norway, analysts say.
A Western counter-terrorism official said the evidence of Somali's involvement suggested to Western governments that the group's leaders retained an ambition to launch attacks.
U.S. prosecutors said Somali was helped in the U.S. plot by Adnan al-Shukrijumah, a Saudi-born operative, and Rashid Rauf, a British al Qaeda-linked militant of Pakistani ancestry.
Paul Cruickshank, a terrorism expert and an alumni fellow at the Center on Law and Security at New York University's School of Law, said the plots "show al Qaeda core remains a threat".
"Westerners are still travelling (from homes in the West) to the tribal areas (of Pakistan) in significant numbers... It gives al Qaeda a chance to turn them around and send them back."
"Some of al Qaeda's most experienced bombmakers are there, and so the area remains a significant danger," he said.
For al Qaeda, carrying out a big attack in the West is key to fundraising among wealthy supporters, some of whom have been demoralised by the failure of the group to strike at the West sucessfully since London bombings in 2005 that killed 52 people.
Bill Braniff, a senior expert at the Combating Terrorism Center at the U.S. Military Academy at West Point, said Somali's siting of the plots in three different countries was intended to reduce the risk that all three would be detected.
"These plots show al Qaeda's trademark complex attack, geographically distributed," he said referring to the movement's style of multiple bombings.
"If they had succeeded, you would have had a huge propaganda effect from attacks in all three countries."
The plots were dealt successive blows when Rauf was reported killed in a U.S. drone strike in Nov. 2008 and Somali was killed by a drone in Dec. 2009.
But Shukrijumah is widely believed to be alive and is now considered "a very prominent member of the inner circle" of operational planning, according to Roger Cressey, a U.S. security expert and president of Good Harbor Consulting.
Western governments are concerned that subsequent groups of militants trained in northwest Pakistan in 2009 and 2010 may have now made their way to the West to prepare other attacks.
Brynjar Lia and Petter Nesser, research fellows at the Norwegian Defence Research Establishment, said the discovery of an alleged al Qaeda cell in Norway suggested the group sought a new capability to strike Europe's periphery after disruption to cells in Spain, Britain, Germany and France.
Terrorist cells hardly ever emerged in a vacuum because they needed supporters to recruit and train, they said.
"Discovery of such cells is usually a strong sign that radicalism and underground extremist networks are on the rise," they wrote in a joint article in CTC Sentinel.