In the eight years since the Sept. 11 attacks, FBI Director Robert Mueller has spent nearly the entire time focused on one enemy: al-Qaeda.
Thousands of terrorist operatives have been killed or captured. Terrorist safe havens and training grounds in Afghanistan where operatives were trained have been destroyed. Military forces largely have shattered al-Qaeda's leadership in Iraq. Meanwhile, Osama bin Laden and top deputy Ayman al-Zawahri, who once closely managed al-Qaeda's day-to-day operations, have been driven into seclusion.
Now, Mueller and counterterrorism analysts are tracking the emergence of a new threat. Al-Qaeda has morphed into a fractured network of small terrorist franchises strewn across Asia, the Middle East and Africa. In Yemen, according to Senate testimony by Director of National Intelligence Dennis Blair, a "jihadist battleground" is rising amid growing political upheaval and poverty. Blair says there are concerns that al-Qaeda could establish a "regional base of operations" in Yemen to train operatives and plot new attacks against the West.
Al-Qaeda's transformation raises an unsettling question: Does its splintering help make the USA and its Western allies safer, or does it complicate efforts to guard against terrorism?
"Yes, they retain the capability of striking overseas," Mueller says in an interview, declining to specify whether the USA is vulnerable to such an attack. "They are still lethal."
Although al-Qaeda's pre-9/11 command structure no longer exists, its smaller terror cells are freer to conceive and direct their own operations, making them increasingly unpredictable. Several analysts worried about a terror resurgence cite evidence that pieces of al-Qaeda are gathering strength in Yemen and Somalia. Yemen's stability is especially crucial to U.S. interests because of its strategic location on the Arabian Peninsula, its access to critical shipping lanes and its vast border with the world's largest oil supplier, Saudi Arabia.
There is "growing concern that al-Qaeda will begin providing social and civil services to the people of Yemen on a scale that could challenge the Yemen government for allegiance," says Gregory Johnsen, a Yemen analyst based at Princeton University.
If al-Qaeda and its affiliates expand in Yemen and other weakened states, he says, the "danger to the U.S. is quite great."
Tom Fuentes, a former FBI assistant director who oversaw the bureau's Baghdad operations, says that "in one sense, you are safer because al-Qaeda no longer has that (pre-9/11) chain of command. On the other hand, al-Qaeda has become so decentralized, it can be harder to stop. … It's like a dormant volcano."
Other terrorism analysts, however, say government officials refuse to admit the threat al-Qaeda once posed largely has passed.
"The evidence is overwhelming," says Marc Sageman, a former CIA officer and prominent al-Qaeda analyst, citing his own analysis suggesting that al-Qaeda's capability to strike targets in the West is declining. "There is not much left of al-Qaeda except in the minds those inside the (Washington) Beltway."
Mueller says much of the danger now comes from a "genre" of hybrid groups spawned by the destruction of al-Qaeda safe havens. Separate groups, which share al-Qaeda's philosophy of eliminating Western influence from Muslim areas, have been inspired by al-Qaeda.