When Abu Mussab al-Zarqawi did time in a Jordanian prison during the 1990s, he spent a lot of long days reading the Qur'an, but no one much respected him for his faith. He was a fighter, and that’s what made him a leader in the cellblock. “He became very popular by being aggressive with the police and defending his people,” says Abdullah Aburumman, a dissident journalist who was in prison with him. Zarqawi was a hoodlum who liked confrontation, combat—and killing. Over the last few years, he consciously built his fame as a terrorist leader in Iraq by cutting off the heads of his hostages in videotaped executions.

Yesterday, this monster who lived by the sword died by an airstrike north of Baghdad. The Iraqi and American governments are, clearly, gleeful, and there’s no question this is a milestone in the war. But, as U.S. and Iraqi officials were quick to say, it won’t end the insurgency, and a look at Zarqawi’s many roles in the Iraqi tragedy suggest his demise may have side effects that are very difficult to predict.

For starters, the best-known face of the enemy in Iraq is now gone. The Bush administration started making Zarqawi a poster boy for terrorism before the U.S.-led invasion in 2003. Eventually, Washington put a $25 million price on his head, elevating him to the status of the world’s most wanted men. He was supposed to be a link between Saddam Hussein and Osama bin Laden, or at least he could be made to seem one.

Yet the more we’ve learned about Zarqawi, the clearer it’s become that he was in the terrorist game for himself. Born Ahmad Fadeel Nazzar al-Khalayleh in the dead-end Jordanian town of Zarqa, he came from a poor but respected family. As a young man, in a society where honor is everything, he repeatedly shamed his parents and his tribe with his reputation as a small-time thug and a fall-down drunk. In the late 1980s, Zarqawi rediscovered his faith, mainly as a source of discipline and a credo for violence. He made his way to Afghanistan, but the holy war against the Russians had given way to sectarian, cynical fights among warlords.

From those early days in Afghanistan, Zarqawi had a distant, sometimes hostile relationship with Osama bin Laden and Al Qaeda ideologue Ayman al-Zawahiri. They did not send Zarqawi to Iraq. He went on his own to link up with a group of radical Islamists in the rough mountains of the Kurdish north, outside Saddam’s control. Zarqawi then developed networks to bring jihadists from Europe and Muslim countries to fight the Americans during the invasion and, more significantly, afterward.

Correspondence from Zarqawi captured over the last three years suggests he was looking for approval from Al Qaeda—or, more precisely, insisting on his appointment as “emir” or “prince” of the organization in Iraq. Bin Laden gave his benediction reluctantly. As recently as last year, bin Laden’s deputy, Zawahiri, warned Zarqawi that his gruesome killings were costing him vital support among the Iraqi people.

On the battlefield, Zarqawi had relatively few fighters. U.S. intelligence has generally credited him with command over only a small fraction of the active insurgents. But what he lacked in numbers, he made up with a sense of spectacle. By late 2004, he had turned suicide bombing into a kind of fatal tourist trade for foreign Muslims who came to Iraq for a quick trip to Paradise. The videotaped beheadings of foreign hostages spread Zarqawi’s infamy far and wide on the Internet. By targeting Shia shrines for horrific bombings, he consciously set out to instigate the sectarian slaughter between Sunnis and Shias that now has gruesome momentum of its own.

Yet the Jordanian’s infamy did not sit well with many Iraqis fighting what they saw as a fundamentally nationalist battle against foreign occupation. Their war is also deadly—they are responsible for the countless attacks on U.S. and Iraqi troops using IEDs (improvised explosive devices). They identify themselves as Sunnis, and their fight does have religious overtones. But they are not nihilists. Their objective, unlike Zarqawi’s, is not endless war and martyrdom leading to a utopian “caliphate” based on historical fantasies.

By the fall of 2004, a lot of Iraqi nationalists were uncomfortable with Zarqawi and wanted to distance themselves from him, or get rid of him. By last year, in some Sunni areas, local tribal leaders made war on Zarqawi’s fighters. But his violence was useful when it targeted U.S. forces, and if he managed to gain some grudging respect, he also became an object of fear, even within the insurgency. Zarqawi was the whip of the rebellion, intimidating tribal sheiks, making sure they did not compromise with the Americans. With Zarqawi gone, it's not clear that anyone else in his organization will be able to play that role.

Conceivably, the effect will be to weaken the insurgency as a whole. But it’s also possible that the homegrown Iraqi rebels, now free of Zarqawi’s evil image, may actually grow in political power and military strength. Following the classic pattern established by many other guerrilla groups in history, they may work through "peaceful" front organizations that actually take part in the Parliament, while also continuing to attack in the field. “Fight and talk" is often a successful strategy for guerrillas looking to assure their people's rights. Zarqawi made talking almost impossible.

With the Jordanian terrorist now out of the way, the Bush administration may be forced to recognize that there are other faces in the opposition, potentially equally dangerous to Washington’s grand designs but politically smarter and less easy to caricature. They, too, will have to be taken into account.