It’s a bit discomfiting to think of a human death as cause for glee, but if there’s an exception to be made, the killing of Abu Musab al-Zarqawi is on the short list.

After all, it was al-Zarqawi’s own ruthless disregard for others’ lives that invited the retaliation that took him out Wednesday in the form of a couple of 500-pound bombs, delivered with laser-guided precision on the not-so-safe house where the al-Qaida leader had gathered with seven henchmen.

As the head of al-Qaida in Iraq, al-Zarqawi was behind the most egregious acts of terrorism to plague the country. He was a promoter as well as a participant in televised beheadings and other odious examples of gratuitous violence. He orchestrated the November 2005 suicide bombings that claimed 56 lives and injured a hundred more in his native Jordan. He openly and defiantly promised to manufacture a civil war in Iraq where the fragile hope for peace and stability hinges on creation of an effective government.

Al-Zarqawi was no mere belligerent in a politically motivated war. His killings were calculated to outrage, shock and terrify. He chose victims whose very innocence fueled a message that there could be no neutral ground in his sectarian showdown.

It’s the nature of war that combatants kill one another. But it isn’t just that al-Zarqawi was killed that gives rise to and explains the joyful reactions described by columnist Trudy Rubin on this page, it’s the fact that he personally was removed as a peril to Iraqis and their peace of mind. Like Saddam Hussein in captivity, al-Zarqawi in the grave is now an empty threat. He won’t return.

Not that abundant threats don’t remain. American and coalition officials universally are acknowledging that al-Zarqawi’s death won’t curb the insurgency. It may well intensify it, as happened in the wake of Saddam’s capture in December 2003.

In time, an ideological heir will seize command of the fanaticism that al-Zarqawi exploited. As insurgents have declared in the past, their loyalty isn’t to an individual leader, it’s to their country and their own twisted interpretation of Islam. A leader who can tap into that allegiance may pick up where al-Zarqawi left off.

To the credit of President Bush and others in his administration, no one is overpromising the significance of Wednesday’s developments. Like the capture of Saddam, the death of al-Zarqawi has been described as having mostly symbolic value. Insurgency and anti-Americanism will persist in Iraq and many other parts of the Middle East, and the larger challenges that confronted the country Tuesday are still waiting for effective solutions.

Even if the death of a vicious killer near Baghdad has minimal political or military effect on the conflict in Iraq, it appeals at a visceral level to a universal craving for justice. Al-Zarqawi got what he deserved, occupants of the civilized world will say, and the $25 million bounty on his head was a sound investment.