As the story goes, Osama bin Laden offered criminals in Chechnya $30 million and two tons of opium in return for 20 Russian nuclear warheads.
The chilling account, contained in a 1999 Arab-language news report, may be apocryphal. But what is certain is that for most of the 1990s, Mr. bin Laden has been trying to get materials to make a nuclear bomb. Acquiring weapons of mass destruction, he has said, is a "religious duty" necessary "to terrorize the enemies of God." Some of his associates (now in prison or witness-protection programs) have recounted efforts to obtain weapons-grade uranium or plutonium.
Today, as the United States bombs terrorist sites and other targets in Afghanistan, the prospect of a nuclear terrorist attack looms larger as a domestic security concern. The likelihood of such an attack, government officials and experts say, may be small - but the possible consequences are too horrific to ignore.
Among the major concerns:
The political instability of Pakistan, a nuclear power in the region that - more so than Russia and former Soviet states - could be Mr. bin Laden's source of nuclear materials. The Pakistani intelligence service used to work closely with Afghanistan's ruling Taliban regime, and many in Pakistan (including, perhaps, military and intelligence sources) support the Taliban and bin Laden. Last week, Pakistan detained for questioning two of its former senior nuclear-weapons scientists - men who have expressed sympathy with the Taliban cause.
Knowledge that with relatively little radioactive material - even low-level waste from a power plant or medical facility - terrorists could construct a "dirty bomb" using simple explosives rather than the more sophisticated and difficult-to-build nuclear weapons. Such devices, hidden in a truck or ship-borne cargo container, could inflict considerable casualties followed by widespread radiation poisoning.
Vulnerability of 10 major nuclear-weapons plants in the US, several of which are near major cities. In mock attacks, the "terrorists" were able to acquire weapons-grade nuclear materials or otherwise achieve their goals in more than half the cases.
In the face of such threats, the US is considering several options.
These include strengthening nuclear-nonproliferation treaties, increasing security at US nuclear-weapons facilities, and buying Russia's leftover nuclear materials. More immediately, some experts suggest preparing US Special Operations Forces to unilaterally disable or seize Pakistan's nuclear weapons. (In the New Yorker magazine this week, investigative reporter Seymour Hersh writes that US military and intelligence agents are training with an Israeli special-operations unit for such a mission.)
In addition, several US lawmakers have said America should be prepared to use its tactical nuclear weapons to prevent or respond to another domestic terrorist attack. Defense Secretary Donald Rumsfeld - repeating long-standing US military doctrine - has not ruled that out.
While the former Soviet Union has been a top concern - officials there can't account for all nuclear-weapons items, and many now-jobless nuclear scientists may be susceptible to bribery - much of the focus is now on Pakistan.
"Pakistan's military government is walking a tightrope between pressure from the Bush administration on one side and anti-American Islamic militants on the other," says Bruce Blair, president of the Center for Defense Information here. "Growing street opposition from the latter could certainly destabilize or even topple the regime, and in the midst of such dissolution, the weakening of nuclear security would inevitably occur."
"The ranks of government and military personnel are also fairly riddled with sympathizers of the radical Islamic faction, posing a distinct risk of insiders colluding to spirit away a bomb or two for bin Laden and other terrorists," says Dr. Blair, a former US Air Force nuclear-missile launch control officer.
Intelligence sources believe that Pakistan has enough plutonium and weapons-grade enriched uranium to make 30 to 50 nuclear bombs or warheads.
"Whether or not all of Pakistan's nuclear explosive material has been converted to nuclear weapons is unknown, leaving the possibility that many kilograms of bulk material may be poorly protected," warns the Institute for Science and International Security. "Security forces at storage sites may be unable to thwart a determined attack by extremist groups allied with bin Laden or the Taliban, particularly if even a small number of guards are sympathetic to the Islamic fundamentalist cause. In the extreme case - should extremists take over the Pakistani government - control over Pakistan's nuclear explosive materials and weapons could be lost irretrievably."
Testimony in the trial of men charged with the 1998 attacks on US embassies in Kenya and Tanzania revealed that bin Laden associates in Sudan may have tried to obtain uranium for a radiological weapon - material that may have originated in South Africa.
Meanwhile, concern for the safety of US nuclear-weapons plants is mounting. A recent report by the Project on Government Oversight warned of "serious security flaws at nuclear- weapons facilities around the country." "When our security efforts do not protect our weapons-grade nuclear materials against over half the mock terrorist attacks, it is well past time for a reassessment," says Danielle Brian of the watchdog group.
Rep. Christopher Shays (R) of Connecticut, chairman of the House National Security Subcommittee, is planning to investigate. "In this critical environment," he says, "it is important for the Department of Energy [which oversees the US nuclear-weapons program] to assure the integrity of basic security measures for the protection of nuclear-weapon facilities ... against both internal and external threats."