THE TERRORIST.

Among those quietly celebrating the death of Abu Musab al-Zarqawi last week, no doubt, were Osama bin Laden and Ayman al-Zawahiri, the leaders of Al Qaeda, who have watched their nominal ally wreck the standing of their organization among Muslims around the world. After Zarqawi began his bloody operations in Iraq, in 2003, support for suicide bombings--the signature of Al Qaeda since the destruction of the American embassies in East Africa, in 1998--plummeted in Islamic countries. Muslims surveyed in the 2005 Pew Global Attitudes Project reported in substantial numbers that Islamic extremism was a threat to their own countries. Jordan, Zarqawi's homeland, seemed to be the exception. Then Zarqawi sent suicide bombers to three hotels in downtown Amman, killing sixty people, including prominent Jordanians and Palestinians, many of whom were celebrating a wedding. The next day, tens of thousands of Jordanians poured into the streets to denounce Al Qaeda.

Zarqawi was the herald of a new generation of terrorists whose roots were in street crime, not in Islamic militancy. A former thief and sex offender, he memorized the Koran while he was in prison, and began issuing fatwas and calling himself "sheikh." "There's certainly been a downgrading of ideological purity," Niall Brennan, a special agent on the joint terrorism task force in the New York office of the F.B.I., told me on the morning that Zarqawi's death was announced. "The next generation is in many respects less disciplined and doesn't have the same respect for command and control." Bin Laden, despite his own appetite for slaughter, disdained Zarqawi's rough manners, prison tattoos, and unruly independence. But after the American invasion of Afghanistan Al Qaeda's founders were immobilized, reduced to making occasional videotapes designed to rouse aspiring jihadis and berate Western leaders. Deprived of the managerial oversight of bin Laden, an international businessman, Al Qaeda began to shape itself around Zarqawi's organizational experience, which is to say that it turned into a gang. This was a model easily replicated by would-be jihadis--as in Madrid, London, Toronto--wherever alienated young Muslims yearned for destruction.

Ayman al-Zawahiri, an Egyptian and the No. 2 man in Al Qaeda, was always closer to Zarqawi than bin Laden was. In 2000, Al Qaeda's Egyptian security chief, Saif al-Adl, helped Zarqawi establish a camp in Afghanistan, near the Iranian border. Young fighters from Jordan, Palestine, Syria, and Lebanon--the area historically called the Sham--gravitated to the camp and formed the Army of the Sham. Although Zarqawi was not yet a member of Al Qaeda, he remained under the protection of the Egyptians. According to Iraq's former interim Prime Minister Iyad Allawi, who claims that he discovered the information in the archives of the Iraqi secret service, Zarqawi travelled to Iraq in 1999, around the same time as Zawahiri. Saddam Hussein was courting Al Qaeda at the time. Inspired, perhaps, by Iran's relationship with Hezbollah, he may have believed that he could use terrorists to conduct his foreign policy without undermining his rule. Contrary to Secretary of State Colin Powell's assertion before the U.N. Security Council, in February, 2003, that Zarqawi provided the link to Al Qaeda in Iraq, bin Laden and Zawahiri spurned Saddam's overtures.

After Saddam was overthrown, Zarqawi installed himself as the leader of the Sunni insurgency in Iraq. His ability to act was an affront to the founders in hiding, who were no longer able to control their own organization. Although Al Qaeda was an exclusively Sunni association, neither bin Laden nor Zawahiri had ever authorized an attack on Shiites. One of Zarqawi's first actions, in August, 2003, was to send his father-in-law on a suicide mission to the Imam Ali Mosque, killing nearly a ...