WASHINGTON — A year ago, U.S. Navy SEALs slipped into a heavily fortified compound in Pakistan and killed the face of international terrorism. There is a growing fear, however, that Osama bin Laden's death didn't even seriously wound the international terror threat.
This past decade — as al-Qaida's core leadership was hunted, scattered and disrupted in Afghanistan and Pakistan — a number of sympathetic groups and individuals sprang up around the world. In the year since his death, their importance in this shadow world has grown.
Richard Fadden, the head of the Canadian Security Intelligence Service, said that this many-headed beast is expected to strike more and more frequently in coming years, and he cited the difficulty of identifying "lone wolf" terrorists — small groups or individuals who self-radicalize.
"These individuals seem to be a mix of terrorists and people who simply have very big personal problems," he told a Canadian Senate committee last week.
An unexpected example emerged in a Norwegian courtroom: Anders Behring Breivik, the anti-immigration nationalist on trial for the murders of 77 people, admitted that he closely studied al-Qaida's methods. He called the group "the most successful revolutionary movement in the world."
Antiterror experts see al-Qaida's influence extending even as the core of the organization is thought to be down to an estimated 100 or fewer followers in its traditional home of Afghanistan and Pakistan's ungoverned tribal areas. A Pentagon spokesman said that even that estimate could overshoot the total number who sleep in Afghanistan on any given night, which might be no more than a few dozen.
Throughout the world, offshoot groups have adopted al-Qaida's label. They have pledged cooperation, shared money and weapons, often trained together or advised each other on al-Qaida methods, and shared both strict Islamist roots and a fervent hatred for the West.
Experts said that five other such groups are considered the most dangerous, or the most capable: al-Qaida in the Arabian Peninsula, based in Yemen; al-Qaida in the Islamic Maghreb, based in Algeria and Mali; Lashkar-e-Taiba of Pakistan; al-Shabaab of Somalia; and Boko Haram, a relatively young Nigerian militancy.
"It's a more dispersed threat. The threat is decentralizing to a broad network of groups. Al-Qaida inspires, but doesn't control, and they work with locals," said Seth Jones, an expert at the RAND Corp. who has advised the Pentagon on Afghanistan and Pakistan.
A deadly example came in 2009 with the rampage at Fort Hood, Texas, where Army psychiatrist Maj. Nidal Malik Hasan, allegedly radicalized online by al-Qaida in the Arabian Peninsula, is accused of shooting dead 13 soldiers. His trial is scheduled to begin in August.
Al-Shabaab has also shown global ambitions — recruiting dozens of youths, mostly from Minnesota but also from Alabama, California and Ohio, to fight an insurgency against Somalia's weak government and an African Union peacekeeping force.
But Tom Sanderson, co-director of the Transnational Threat Project at the Center for Strategic and International Studies in Washington, said one of the most puzzling questions is why al-Shabaab — so far — hasn't lashed out.
"The Shabaab network inside the United States is tailor-made for what al-Qaida wants to accomplish in this country," he said. "They have ties to al-Qaida, they have the rhetoric. It's not a very big stretch to turn that into attacks in the United States."