By Steve Coll
The Washington Post
Sunday, February 6, 2005; Page B01

At a conference on the future of al Qaeda sponsored by Los Alamos National Laboratory last month, I posed a dark question to 60 or so nuclear weapons scientists and specialists on terrorism and radical Islam: How many of them believed that the probability of a nuclear fission bomb attack on U.S. soil during the next several decades was negligible -- say, less than 5 percent?

At issue was the Big One -- a Hiroshima-or-larger explosion that could claim hundreds of thousands of American lives, as opposed to an easier-to-mount but less lethal radiological attack. Amid somber silence, three or four meek, iconoclastic hands went up. (More later on the minority optimists. They, too, deserve a hearing.)

This grim view, echoed in other quarters of the national security bureaucracy in recent months, can't be dismissed as Bush administration scaremongering. "There has been increasing interest by terrorists in acquiring nuclear weapons," Mohamed ElBaradei, the Egyptian director general of the International Atomic Energy Agency, the world's chief nuclear watchdog, said in a recent interview, excerpts of which were published in Outlook last Sunday. "I cannot say 100 percent that it hasn't happened" already, he added, almost as an afterthought.

Worried yet? Then you might agree that there is too little specific, rigorous, apolitical discussion of this threat available to the public. In an era when Americans know they have reason to be afraid -- yet seem at times to know more fear than reason -- even the unthinkable requires transparent debate. Here's a provocation, in service of the cause of inspiring such debate: In focusing all-out on nuclear aspirants such as Iran and North Korea, the United States may be distracting itself from an even graver problem.

A time machine traveler tuning in to the American discussion about nuclear proliferation early in 2005 might think the dial had been set to 1965 by mistake. Then as now, American arms control debate focused heavily on the fear that too many governments would go nuclear. The Bush administration recognizes that catastrophic terrorism has changed the context in which states own or seek to acquire nuclear weapons. Yet traditional nonproliferation thinking, focused on governments, still dominates U.S. policy. When President Bush mentioned nuclear dangers in his State of the Union address last week, he referred only to the problem of governments seeking weapons. That challenge remains urgent, but it does not explain the gloom at Los Alamos.

A startling number of U.S. nuclear and terrorism specialists I have talked with during the last year believe that the threat of a jihadi nuclear attack in the medium term is very serious. They recognize that as a technical and scientific matter, such an attack can be very difficult for private groups to pull off. They fear it anyway. They may have professional incentives to conjure the worst case, but I believe this to be their honest assessment.

At the center of their pessimism stands the unique figure of Osama bin Laden, still at large, still espousing his ideology of mass-casualty attacks against Americans, with a special emphasis on nuclear weapons -- an ideology that seems destined to outlive him.

Some of these analysts, confronting uncertainty, may lean toward pessimism because, with the stakes so high, they would rather be wrong than fail to anticipate a preventable attack.

Back in 1998, when he was still an obscure White House aide, Richard Clarke was accused of scaremongering about a little-known terrorist named Osama bin Laden in order to win budgetary funds from Congress.

"I would be delighted three or four years from now to say we've wasted money," he replied. "I'd much rather have that happen than have to explain to the Congress and the American people why we weren't ready, and why we let so many Americans die."

September 11 taught us that Chicken Little sometimes gets it right. But the failures to correctly assess Saddam Hussein's weapons of mass destruction showed that he sometimes gets it wrong.

Once again, the stakes are very high and once again, the adversary is hidden and dynamic. Among other difficulties, the al Qaeda near the heart of the current nuclear threat is not the same al Qaeda feared by Clarke seven years ago.

At its birth in 1988, al Qaeda was a poorly equipped summer camp for volunteer soldiers near Khost, Afghanistan. By the summer of 2001, it had a formal headquarters, management committees, a dozen or more training facilities, global recruiting centers, a few thousand sworn members and thousands of other followers.

Today al Qaeda is no longer much of an organization, if it can be called one at all. Its headquarters have been destroyed, its leadership is scattered or dead or in jail. Osama bin Laden remains the chairman of the board, increasingly a Donald Trump-like figure -- highly visible, very talkative, preoccupied by multiple wives, but not very effective at running things day-to-day.

He is an unusual terrorist leader in that he has produced a broad and sustained body of interviews, pamphlet essays and videotaped speeches, even after going into hiding. In these lie the jihadi nuclear doctrine, in plain sight.

Since the late 1980s and certainly since 1991, bin Laden has seen the United States as the principal invader of the Muslim world because of its support for the Saudi royal family, Israel and other Middle Eastern governments he labels apostate. In often tedious debates with comrades during the 1990s, he has argued that only by attacking distant America could al Qaeda hope to mortally wound the Middle East's frontline authoritarian governments.

His inspiration, repeatedly cited in his writings and interviews, is the American atomic bombing of Hiroshima and Nagasaki, which he says shocked Japan's fading imperial government into a surrender it might not otherwise have contemplated. Bin Laden has said several times that he is seeking to acquire and use nuclear weapons not only because it is God's will, but because he wants to do to American foreign policy what the United States did to Japanese imperial surrender policy.

Listening to him on tape after tape, it is difficult to doubt bin Laden's intent. There is evidence that he and his allies have experimented with chemical and biological weapons, typically low-level toxins. But in public, bin Laden talks mainly about nuclear bombs.

As far as is known, he and his followers lack the capability to carry out a significant attack. Given the pressure he is currently under, it is difficult to imagine how bin Laden himself will ever reacquire the space he would need to carry out or closely supervise such a complicated attack himself.

Yet as long as he is at large, he will at a minimum seek to inspire others to act on his behalf. He has already helped to radicalize several individual scientists associated with Pakistan's nuclear program. And by now bin Laden's rationale for attacking the far enemy with massive force has been globally distributed, on satellite television and across the Internet.

But wait, you may say: There hasn't been an attack of any kind on U.S. soil since Sept. 11., 2001. There are probably multiple explanations for this fact: a lack of effective al Qaeda cells in place; U.S.-led disruption efforts; and bin Laden's inability so far to inspire any significant following in the United States. But many al Qaeda watchers also believe that bin Laden or his followers may be husbanding their resources, planning and waiting until they can carry off an attack big enough to match or exceed the last.

What is the specific character of the threat as it may unfold over several decades?

Imagine the faculty lounge in the theoretical physics, metallurgy and advanced chemistry departments of an underfunded university in Islamabad or Rabat or Riyadh or Jakarta. The year is 2015. Into the room walk a group of colleagues -- seven or eight talented scientists, some religiously devout, all increasingly angry about events abroad. At night, between sporadic electricity outages, they watch satellite television and chat in cyberspace, absorbing an increasingly radical, even murderous outlook toward the United States. By day, as they sip coffee and smoke furtively in each other's company, these scientists spontaneously form a bond, and from that bond emerges a resolve to act -- by launching a nuclear or biological attack on American soil.

Unlike states, which so far have proved deterrable by the threat of retaliation even when led by madmen, this faculty cell may be utterly indifferent to and beyond the reach of the traditional mechanisms of nuclear deterrence.

This scenario of radicalization tracks the narratives preceding half a dozen recent conventional al Qaeda attacks, including the Madrid bombings last March and the suicide bombing in Casablanca in 2003. As terrorism analyst Marc Sageman has documented, the Madrid conspiracy highlights an emerging problem of spontaneous cell generation, incubated by al Qaeda ideology. The conspiracy involved independent, fluid group decision-making fueled by mixed motives, including religious idealism, criminality and greed.

The cells that carried out the Madrid and Casablanca attacks did not contain talented scientists. But the notion of a semi-independent cell of self-aggrandizing Islamist scientists is, unfortunately, not invented. The faculty lounge cell is just an extrapolation of the story of A.Q. Khan,the founder of Pakistan's nuclear program, who sold secrets to global customers for profit.

From where might such undeterrable jihadi nuclear cells emerge during the next several decades?

The movement bin Laden now seeks to inspire draws from at least two channels. One is the spontaneous identification of individual Muslims with his cause -- self-declared affiliations by jihadis acting essentially on their own. These are often alienated, transnational migrants in the pattern of Ramzi Yousef, architect of the 1993 World Trade Center bombing, who was born in Pakistan, raised in Kuwait, educated in Britain, trained in Afghanistan and inspired by targets in New York.

The jihadi movement also draws from more conventional guerrilla movements, especially a loose coalition of jihadi-infected insurgencies from Southeast Asia to north Africa. Some of these groups seek national status in separatist causes.

Like government leaders throughout the atomic age, they may be reluctant to jeopardize their territory and political claims by involving themselves in a spectacular attack on the United States -- just as Hamas, for example, has been reluctant to target Americans even while endorsing much of bin Laden's creed. Yet in the long run, infected by Osama's ideology, some of these guerrilla groups may be difficult to deter.

In Pakistan today, some Islamist insurgents, such as those in the frontier territory where bin Laden is presumed to be hiding, receive almost-state sponsorship or failed-state sponsorship. Individual officials or sections of a corrupt bureaucracy join with these radicals for a variety of reasons -- cash payoffs, ideology, venality, or a blend of all three. These fluid relationships threaten to render irrelevant the traditional postures of nuclear deterrence, in which governments frighten other governments into nuclear restraint, usually by credible threats of massive retaliation.

President Bush's pledge after 9/11 to make "no distinction between the terrorists who committed these acts and those who harbor them" does not seem likely to intimidate a future jihadi nuclear cell. If it had been discovered that the A.Q. Khan network intended to carry out a direct attack on the United States, who in its ranks would be deterred by Bush's threat? The government of Pakistan, which today claims it did not know what Khan was doing? Khan himself, who seems to have been in it for money and glory? His business partners in Malaysia and Dubai, with no political assets to defend?

So it's not hard to play Chicken Little. The next question is: What to do?

A sustained campaign to contain the jihadi nuclear threat might draw on diverse approaches. More aggressive efforts to secure nuclear materials, a reformulation of deterrence strategy to address gray networks, and a broad reduction in the sources of jihadi radicalization would be places to start. National laboratories such as Los Alamos helped identify Soviet nuclear weapons scientists after the collapse of communism; they are needed now in the Middle East. Helpful above all would be to elevate all these issues to the prominence accorded Iran and North Korea.

Fear not: I haven't forgotten about those Los Alamos optimists, the ones who raised their hands to say that the chance of any nuclear fission attack on U.S. soil during the next few decades was less than 5 percent. Why are they hopeful?

They, too, do not doubt bin Laden's intent, but they question the tradecraft of his most committed followers. They read the history of terrorism in the atomic age and see no case where a nuclear cell has come as close to launching as governments repeatedly have done. They suspect jihadism has hit its high-water mark, that it is in decline even if we cannot see it clearly yet. They point out that too much focus on worst-case WMD scenarios may blind us to al Qaeda's potential to carry out catastrophic attacks by conventional means -- a problem that plagued American analysis of bin Laden in the run-up to 9/11.

And a few of the optimists joked about the greatest deterrent of all: The requirement, in the faculty lounge cell scenario, that half a dozen tenured, ornery and egotistical physicists cooperate with each other on a demanding project. ("Yeah -- but what about the graduate students?" one professor in our group quipped. "They're dangerous!") It's cheering to place one's faith with these optimists, to stop worrying and ignore the jihadi bomb. But it might be safer, and more reassuring, if the pessimists involved in our defense had some running room to chase the new enemies they see inexorably rising.

Author's e-mail: colls@washpost.com

Steve Coll, The Post's managing editor from 1998 to 2004 and now an associate editor, has written about nuclear proliferation issues for more than a decade. He is the author of "Ghost Wars: The Secret History of the CIA, Afghanistan, and Bin Laden, From the Soviet Invasion to September 10, 2001," published in paperback last month.