Combating simple, yet deadly, forms of terrorism

While it is not yet certain who organized the attempted car-bombing in Times Square this weekend, the incident marks the domestic introduction of familiar terrorist techniques that may be harder to thwart than those to which the U.S. homeland security apparatus became attuned after Sept. 11.

Terrorism experts are unable to definitively say why Islamist terrorists have not successfully pulled off a large-scale hit on the United States since the 2001 attacks. Some have argued that terrorists' apocalyptic mind-set and religious vision of the "end of days" requires an encore at least as spectacular as Sept. 11. Some theorize that counterterrorism efforts for the time being have rendered terror groups incapable of mounting such an operation, and that they are saving America for a spectacular reprise on the scale of Sept. 11 once they regain the capability.

But the attempt to bring a less destructive terrorist technique to bear in New York may put the lie to that explanation. While we have not seen a single attack as horrific as the collapse of the twin towers, al-Qaeda and its followers have killed far more people -- Americans and other nationalities -- using various forms of improvised explosive devices in war zones and ostensibly peaceful locales. Some 65 percent of the military casualties in Iraq and Afghanistan have been from improvised explosive devices, the Army Times reported last year. Many of them, like the Times Square device, are activated by or packed in vehicles; several of al-Qaeda's most devastating attacks since 2001 -- such as bombings that killed 202 people, mainly tourists, in Bali in 2002 -- involved such devices.

Terrorist tactics spread by virtue of success. Consider the number of airline hijackings in the 1960s and 1970s. These days, vehicle-borne IEDs are suited to urban spaces, in which cars are commonplace and inconspicuous and dense populations mean relatively high numbers of casualties. These points would not be lost on jihadist leaders and aspiring acolytes, who tend to be students of their craft.

Even if we don't yet know who was behind this attempt -- though U.S. officials have deemed it terrorist activity, and a key leader of the Taliban in Pakistan has claimed credit -- we do know that al-Qaeda is pragmatic and adaptive. However precious al-Qaeda may deem the "stun value" of the next big attack on America, the effectiveness of U.S. actions to thwart such an incident was eventually likely to compel it to downgrade expectations. Now, perhaps, al-Qaeda has. The attempted Christmas bombing on a U.S. airliner was certainly a less complex and ambitious operation than Sept. 11 -- or, for that matter, the 2004 Madrid attacks, the 2005 London subway bombings or the 2006 Heathrow plot. Even if the core group has not given up on the grand apocalyptic attack, anti-terrorist activity in Pakistan has compelled it to devolve operational authority to regional affiliates and homegrown terrorist aspirants who are free -- if not encouraged -- to use less operationally demanding methods. And this sort of urban warfare was long ago introduced and developed in places such as Belfast and Bilbao, then refined and expanded in Iraq and Afghanistan, with the advent of explosively formed penetrators (EFPs) and "sticky bombs," which are smaller and more precise than car bombs and may be harder to detect.

It would be a mistake for al-Qaeda's targets to regard that tactical adjustment as any kind of victory. Old techniques such as car and bus bombs, though not as massively lethal as the new ones -- such as turning a hijacked airplane into a guided missile, or detonating a "dirty bomb" or even a small atomic device -- would signify mainly that jihadists are starting to consider more frequent terrorist attacks that are far easier to execute and get away with. This kind of approach won favor with Northern Ireland's Provisional Irish Republican Army in its drive to unite Ireland, and with the Basque separatist group Euskadi ta Askatasuna (ETA) in Spain. These groups, which evolved into highly capable and professional organizations, challenged civil order and palsied society for decades, claiming roughly 2,200 and 1,000 lives, respectively.

A sustained urban terrorism campaign could disrupt American society as profoundly as the Sept. 11 attacks -- if not more so. As the British and Spanish security forces learned, there is a delicate balance between vigilance and panic, resilience and over-preparedness, vigorous law enforcement and a police state. Since 2001, the New York Police Department has struck that balance admirably. As Mayor Michael Bloomberg noted this weekend, New Yorkers were lucky the bomb malfunctioned. But it is not just the NYPD that may have to adjust to a new set of threats. Fortunately, we have European experience and wisdom to draw on.

Steven Simon, a senior fellow at the Council on Foreign Relations and Jonathan Stevenson, a professor of strategic studies at the U.S. Naval War College.