Where the Terrorism Threat From al Qaeda Is Headed

The attacks in Mumbai this winter shocked the counterterrorism community, not only for the brazen nature of the assault and its high death toll but also because of the low-tech manner in which such carnage was brought to the streets of the Indian city. It was yet another reminder of the ever evolving nature of the terrorist threat.

Al Qaeda, which was not directly linked to the attacks in India, has historically striven to pull off more dramatic, deadly, and complex plots than the one in Mumbai, meaning its attacks have been less frequent and more difficult to bring about. But intelligence experts worry about what lessons Osama bin Laden and his followers might take from the brutal effectiveness of a handful of men armed with automatic weapons.

Whatever bin Laden may conclude, al Qaeda remains one of the greatest threats to the homeland for the foreseeable future, intelligence and defense experts agree. "Al Qaeda has suffered serious setbacks, but it remains a determined, adaptive enemy, unlike any our nation has ever faced," outgoing CIA chief Michael Hayden said recently. The group "is both resilient and vulnerable."

Despite the resurgence of the Taliban in Afghanistan and in the tribal regions of Pakistan, there has been a rise in the number of high-ranking al Qaeda leaders reported killed. On New Year's Day, Usama al-Kini and Sheik Ahmed Salim Swedan, both Kenyan nationals wanted in connection with the 1998 bombings of U.S. embassies in Africa, were killed in an apparent U.S. airstrike. In November, a similar attack killed Rashid Rauf, who was wanted in connection with a plot to use liquid explosives to down trans-Atlantic airliners. In 2008, there were more than 30 missile strikes against suspected al Qaeda targets.

Yet al Qaeda has still managed to mount or inspire attacks around the globe, from the killing of Benazir Bhutto and the Marriott hotel bombing in Pakistan to the unsuccessful attacks against the airport in Glasgow, Scotland. U.S. intelligence officials say al-Kini was involved in the Marriott attack and an unsuccessful bombing attack on Bhutto several months before she was assassinated.

For intelligence agencies and the U.S. military, the main challenge is to understand the reasons for the group's resiliency and to figure out how to exploit its vulnerabilities, such as ideological rifts. While the threat of an attack with weapons of mass destruction always tops U.S. fears, there are other, perhaps more likely, scenarios that worry counterterrorism officials, including more low-tech attacks and possible cyberassaults.

Lessons from Mumbai. The vast majority of terrorist strikes worldwide involve explosives or guns to wreak havoc. In Mumbai, using grenades and machine guns, terrorists killed more than 170, wounded 300, and paralyzed the city. It was the second-largest global terrorist attack since 9/11. (Also last year, terrorists in the United Kingdom tried using a flaming sport utility vehicle to ram the Glasgow International Airport.)

The Mumbai attack was so shocking that New York City immediately revised its training for police officers to include the use of machine guns that may be used in response to such an incident. The NYPD is also looking for ways to disrupt cellphone communications during an attack, after the Mumbai perpetrators used cellphones repeatedly throughout their three-day rampage. "You could envision that happening in any American city," says Kenneth Wainstein, the president's homeland security adviser. "It's something we're very worried about."

Just as the West relies on small groups of commandos to ferret out terrorists, so, too, have these terrorist groups come to rely on small, innovative, disciplined units to achieve outsize results. David Kilcullen, a coauthor of the Army's Counterinsurgency Field Manual , says Mumbai marked a departure from the traditional terrorist modus operandi. "[The Mumbai attacks] have all the hallmarks of a Special Forces raid, closer to a commando raiding activity than a traditional al Qaeda-style terrorist attack."

That's something that counterterrorism officials have long feared. This winter, a group of men were convicted of planning a machine gun attack on Fort Dix in New Jersey. "After 9/11, the great fear was that terrorists would attack shopping malls with small bombs or machine guns. It's nearly impossible to stop, cheap to fund, and as likely today as it was then," says Jamie Smith, a retired CIA officer who now heads a private security firm.