In assessments of the Bush presidency, the failure to bring Osama bin Laden to justice should be noted as a significant disappointment. On the bright side, al-Qaeda has been prevented from mounting any significant attacks on the U.S. homeland. In that respect the most important objective of the antiterrorism strategy has been met. But Bush leaves office with a lingering sense of incompleteness, having not achieved the one thing that would have enabled him to use the word “victory” in the War on Terror without caveat.

What would most of the last eight years have been like without bin Laden? He defined the Bush years more than any individual except the president himself. His actions enabled sweeping use of presidential war powers, and brought about significant government reorganizations in the realms of defense, intelligence, and homeland security. It is unlikely that most of these changes will be undone by Bush’s successor, with a few high-profile exceptions.

But while the United States was busy executing an unprecedented and largely successful war on global terror networks, it could not manage to erase the most visible manifestation of terrorist violence. There is an awful symmetry of the failure to apprehend bin Laden with the glacially slow rebuilding effort on the site of the former World Trade Center towers. In the years after 9/11 the U.S. experienced the greatest building boom in its history, and could not complete a fitting structure on some of the most valuable real estate in the world. The Freedom Tower could have been a mark of our pride and resilience in the face of adversity, and probably will be someday, but the ribbon cutting will fall to President Obama or his successor if the 2013 estimated completion date holds.

Almost exactly four years ago I visited this subject in an article titled “No Substitute for Victory.” I still believe it, but barring the unexpected it will not be Bush who enjoys the laurels, if there are any. In that article I noted the way that the failure to capture or kill bin Laden was being rationalized. Former CIA number-three man A. B. “Buzzy” Krongard believed if bin Laden were removed from the picture a destabilized al-Qaeda would lash out at us-as though the terrorists weren’t trying their best to do so every single day already. Steve Simon of the RAND Corporation, head of the Transnational Threat Office of the National Security Council under Bill Clinton, reasoned that it would be best not to take down bin Laden because “killed, he will be a martyr, maybe even more powerful.” Why a living bin Laden, the man who is responsible for the deaths of almost 3,000 Americans and others on a single day, is a less powerful, less potent symbol than a dead bin Laden is anybody’s guess. Let’s not overthink this. Which looks more powerful symbolically-the mightiest country in the world that cannot find a single person, or the terrorist mastermind who has evaded justice for over seven years? Who gets the opportunity to plot his own dramatic comeback-the live terrorist or the dead one?

But the Bush administration consistently downplayed the importance of taking out bin Laden. Now Barack Obama is using almost identical language to describe his objectives in the war against al-Qaeda. “Bin Laden and al-Qaeda are our number one threat when it comes to American security,” he said. And containing their activities is good enough. Whether bin Laden “is technically alive or not” is not so important, though Obama said his “preference obviously would be to capture or kill him.” This position is perfect bin Laden triangulation. There is no way to say that Obama will have failed if bin Laden remains “technically alive,” yet he still gets credit if Osama winds up technically dead.

It is of course possible that bin Laden is dead already. The recent tapes could be a mix of old material with a bin Laden imitator supplying commentary on recent events. A strangely choppy video released in September 2007 featured someone who did not quite resemble bin Laden, or perhaps it was him with a false beard. Bin Laden did not make an appearance for the most recent 9/11 anniversary, or for the most recent election. Meanwhile his No. 2, Ayman al-Zawahiri, shows up frequently on videos and on tape. In his latest, Zawahiri praises “our fighting sheikh Osama bin Laden (may Allah protect him).” Sure, he could be doing that just to make us think bin Laden is alive, to deny us the satisfaction, but I doubt it.

Bin Laden may be lying lower than usual because of the long-overdue stepped-up use of armed drones over Pakistan. Also, no one has attempted publicly to claim leadership of his movement, which would surely happen if he were gone. Extremist groups abhor a vacuum, and the leadership of al-Qaeda is a plum position. There were some interesting signals that such a struggle started in the fall of 2002, but order was quickly restored

. This was also when Iran began to provide protective custody (they call it house arrest) to numerous al-Qaeda leaders. There is tremendous disagreement in the U.S. intelligence community over what Iran’s role in all this has been, and it is something we will probably have to wait a long time to learn.

Maybe Osama will be the Nana Sahib of the 21st century, a figure whose fate remains a mystery, who will be sighted periodically but never conclusively, whose significance will fade as larger issues take the world stage, until the march of time forces the conclusion that he has expired, unheralded, in some dark corner of his underworld. A pathetic whimper for the man who entered our lives with a bang. There is justice in that, of a sort. But not the type that satisfies, not with the finality, the certainty that we should be able to expect.

Meanwhile Osama bin Laden is left with if not the last laugh then at least one of the best. He outlasted President Bush. Our officialdom dismisses this as insignificant. Bin Laden may live, they reason, but he is marginalized, ineffective, and unable to show his face. Yet bin Laden remains a source of legitimacy, strength, and spirit for those who follow him, or would aspire to be like him. He is if nothing else the one who got away with mass murder. This fact should be hateful to us. His demise should not be a “preference” of our leaders but a hard and unyielding objective. It is the nature of a war on terrorism that there is no reasonable way to mark its end, no surrender document, no capital to occupy. But since we can bring bin Laden to justice, we must. It will not end terrorism, it will not make us safe. But it will satisfy our need for completeness, for closure. Taking down bin Laden will, if only for a moment, quicken the pulse, lighten the step, and moisten the eyes of every American. Assuming we can get the job done.

— NRO contributor James S. Robbins is senior fellow in national-security affairs at the American Foreign Policy Council, and author of Last in Their Class: Custer, Pickett and the Goats of West Point.