An Oct. 26 article on the Bush administration's efforts to halt nuclear proliferation incorrectly said that Greg Thielmann was the director of strategic proliferation and military affairs in the State Department's Bureau of Intelligence and Research until 2003. Thielmann left the position in 2002. (Published 10/27/04)

In the tumultuous first year after Sept. 11, 2001, President Bush confronted a deluge of classified threat reports about the spread of nuclear weapons technology to unfriendly hands.

An atomic black market, operating on three continents, was funneling bomb-making equipment to Libya -- and to customers unknown. Iran had made unexpected strides toward a weapon along a route concealed for more than a decade. North Korea, judged in June 2002 to be years away from domestic uranium enrichment, was discovered a month later to be on the brink of it. The National Intelligence Council assessed that there was "undetected smuggling" of "weapons-grade and weapons-usable nuclear materials" known to have been stolen in Russia on four occasions between 1992 and 1999. And two senior figures from Pakistan's nuclear establishment, who met with Osama bin Laden a month before the attacks on the World Trade Center and the Pentagon, were failing polygraph tests about the purpose of their trip.

No president before Bush faced such a diversity of nuclear dangers. Some threats came from hostile nations. Others were stateless: a business underworld that supplied the makings of a nuclear weapon, and a jihadist underworld that sought to buy one. The profusion of threats laid competing demands for Bush's attention in a climate of uncertainty and rapid change.

Like the "war on terrorism," which it often intersected, Bush's efforts against nuclear proliferation followed many paths.

Bush has struggled -- thus far without success -- to roll back significant nuclear advances in North Korea and Iran.

In the summer of 2002, both countries made or disclosed leaps toward self-sufficiency in manufacturing the principal ingredient of a nuclear weapon. Bush demanded that Pyongyang and Tehran reverse course, but his national security team could not agree on policies to induce or compel those governments to submit. The stalemate left three secret overtures from Tehran unanswered and a presidential directive on Iran unsigned after 31 months of drafting attempts.

A similar impasse over North Korea -- before and after the Pyongyang government removed enough plutonium from U.N. supervision to build five or six bombs -- left Bush's team with a policy that one frustrated participant called "no carrot, no stick and no talk." Administration officials acknowledge that North Korea and Iran have accelerated their nuclear progress but say the damage dates from decisions made by President Bill Clinton.

At the same time, further from public view, Bush worked to penetrate and close the first private marketplace of the atomic age: Abdul Qadeer Khan's Pakistan-based distribution network. Bush's partnership with British Prime Minister Tony Blair followed a trail of underground transactions to Libya and persuaded that country to abandon an ongoing nuclear weapons program, a signal success. After resisting British advice to intervene sooner, however, Bush discovered that the decision to "wait and watch" allowed the nuclear black market to fill significant purchase orders from North Korea. The investigation has since been stymied in Pakistan.

Bush also resolved to deny what he called "the world's most destructive weapons" to terrorists -- the proliferation front to which he has devoted the principal resources of his presidency. That resolve, and the strategy he devised to achieve it, brought him to war in Iraq against a source of weapons he did not find.

No other set of subjects divided Bush more sharply from his intelligence establishment. Although the CIA judged, wrongly, that Iraq had resumed efforts to build a nuclear device, U.S. intelligence agencies described other unfriendly states as far more advanced. Assessments throughout Bush's presidency, moreover, said the least likely route to a terrorist nuclear weapon was deliberate transfer by a state.

This examination of the record by The Washington Post explores the priorities Bush set, the beliefs he formed, the choices he made and the ones he left unmade when faced with deadlock among his advisers. It draws on interviews with U.S. participants in leading events and their counterparts from U.N. agencies and governments in Europe, Asia and the Middle East. Some of those interviewed shared portions of their notes and confidential records.

Undersecretary of State John R. Bolton was the only Bush administration official who agreed to speak on the record for this article. The administration made available two other political appointees for interviews on the condition that they not be identified. Officials who spoke without permission, many of them senior career analysts and policymakers, said their standing with the White House would be at risk if they were quoted by name.

Bolton described Libya's nuclear disarmament and the exposure of Khan's black market as highlights of the Bush record, and said North Korea and Iran might be further along if not for the administration's tough stand.

"The question is not, 'Is the status of the pursuit of nuclear weapons more advanced?' " he said. "The question is, 'What would have happened and how much worse would it have been if we hadn't pursued a more aggressive policy?' "

'A Right to Disagree'

Soon after Bush took office, three dozen analysts from around the government gathered for a full-day conference in Chantilly to sift top-secret, compartmented intelligence. If al Qaeda obtained a nuclear weapon, they asked, where would it come from?

Defining that threat, and its source, would top the list of urgent assignments for U.S. intelligence after Sept. 11.

"We thought the highest probability of their getting anything would be to buy a weapon full up" from corrupt or ideologically allied insiders in the chain of custody in a nuclear weapons state, said Richard A. Clarke, who organized the intelligence summit as Bush's national coordinator for counterterrorism. "We assumed the place most likely to supply that would be the former Soviet Union. They had more weapons, and there were more people involved in guarding them, compared to a fairly limited number of weapons in Pakistan that were fairly well accounted for."

Russia's risk factors were widespread corruption, a Chechen insurgency linked to radical Islamists elsewhere, and what Graham Allison, an assistant secretary of defense under Clinton, has called the "Willie Sutton Principle." In a recent book, "Nuclear Terrorism," Allison wrote, "When asked why he robbed banks, Sutton answered: 'Because that's where the money is.' " The logic of deterrence offered two strong reasons, U.S. intelligence judged, to doubt any government would deliberately transfer such a weapon. For one, al Qaeda might turn the bomb against its source. For another, the isotopic signature of a nuclear device can be traced to its country of manufacture, exposing that nation to catastrophic retaliation.

Al Qaeda's behavior suggested it had done much the same market survey. In 1998, in one of several similar cases, Israeli intelligence reported that bin Laden paid more than 2 million pounds to a middleman in Kazakhstan who promised to deliver a stolen warhead -- though there is no evidence that delivery took place.

A National Intelligence Estimate on nontraditional threats, completed long after Bush had committed himself to war in Iraq, reprised earlier judgments. Black-market sales from "the former Soviet Union, Pakistan -- those were the highest risks," said Richard A. Falkenrath, a former White House official who co-wrote Bush's classified May 2002 strategy "Combating Proliferation of Weapons of Mass Destruction."

Bush took a different view. In the State of the Union address of Jan. 29, 2002, the president declared he would keep "the world's most destructive weapons" from al Qaeda and its allies by keeping those weapons from evil governments. Much later -- after applying that doctrine in Iraq -- he told a campaign audience in Pennsylvania, "We had to take a hard look at every place where terrorists might get those weapons and one regime stood out: the dictatorship of Saddam Hussein."

"It was our job to identify the threat as we saw it," said Greg Thielmann, who was director of strategic proliferation and military affairs at the State Department's Bureau of Intelligence and Research until 2003. The White House, he said, "has a right to disagree."

In Pakistan: Musharraf or Khan

On March 27, 2001, Pakistani President Pervez Musharraf threw a banquet for Abdul Qadeer Khan.

A German-trained metallurgist, Khan had led Pakistan's nuclear weapons program from its infancy. Musharraf's celebration marked Khan's unexpected retirement.

By then, Musharraf had good reason to know Khan was leading a secret life. The U.S. government, very carefully, had told him so.

A combined British-American intelligence inquiry into Khan, among the most closely held secrets of the Bush administration's first year, was progressively surpassing its worst fears. What London and Washington had struck upon -- beginning in Clinton's final year -- was a danger not seen before: a global private marketplace in the makings of a nuclear bomb.

By the time Bush arrived in office, according to a recent British government report, the CIA and Britain's Secret Intelligence Service knew that "Khan was at the center of an international proliferation network" supplying uranium equipment "to at least one customer in the Middle East, thought to be Libya." Khan not only dealt in designs but also had begun mass production of components.

The U.S. government had a dilemma. The picture was alarming, incomplete and dependent on sensitive intelligence sources. And the man at the center of suspicion had a stature in Pakistan that easily exceeded Musharraf's.

The Bush administration sent envoys to Islamabad with deliberately opaque words of warning. Something was amiss at Khan Research Laboratories, they said, and its secrets were being marketed abroad. One official said Assistant Secretary of State Robert Einhorn told the three-star general overseeing Pakistan's strategic nuclear force: "Either you are not on top of this or you are complicit. Either one is disturbing."

U.S. officials did not mention Khan by name. They feared a confrontation that could break Musharraf's grip on power and, in the worst-case scenario, Thielmann said, bring about a "fundamentalist government in Pakistan that had nuclear weapons."

According to a senior Pakistani adviser, Khan's retirement banquet was Musharraf's attempt to satisfy Washington. "In order not to raise suspicions" at home, the official said, Musharraf retired another top official the same night.

The Bush administration, one U.S. policymaker said, welcomed Musharraf's decision to close the spigot on his nuclear technology. "At least," the policymaker said, "that's what we hoped it was."

It did not turn out that way. Khan changed titles but kept access to his labs. His global sales flourished.

By the second half of 2001, "the British government was certainly getting nervous that A.Q. Khan was continuing to supply stuff that might not be detected before we intervened to close it down," said a high-ranking British official with access to contemporary intelligence reports.

Most alarming was this: The CIA and British intelligence saw that Khan had more than one customer, but they could identify only Libya.

After the Sept. 11 attacks, Bush demanded a change in Pakistan's relationship with the Taliban and al Qaeda. Deputy Secretary of State Richard L. Armitage was preparing a list of "non-negotiable" demands for Pakistan's military intelligence chief, Mahmud Ahmed. The administration briefly debated: Should Khan be on the list?

Feroz Hassan Khan, who was then a director in the army's strategic plans division, said in an interview that "there would have been a positive response" if Armitage had used that moment to demand action against the nuclear black market. But Bush's national security team believed the United States could push Musharraf no harder.

Six weeks later, then-CIA Director George J. Tenet brought Bush news that a participant in the meeting described as sending the president "through the roof": Two Pakistani nuclear scientists, Sultan Bashiruddin Mahmood and Chaudhary Abdul Majid, had met with bin Laden in Afghanistan that summer. Tenet did not know whether they had a connection to Abdul Qadeer Khan -- much later, officials said, it grew clear they did not -- but he rushed to Islamabad to demand U.S. access to their questioning.

Still, Tenet held his silence on Khan. Conversations with U.S. officials were so elliptical at the time, a high-ranking Pakistani official said, that "we wondered if maybe the real American motive here was to just learn more about our [nuclear] capabilities." He added, "We weren't going to give them any kind of information on that."

March 2002 brought the first intelligence assessments that Khan had moved his base outside Pakistan, that he controlled the business through associates in Dubai and had "established his own production facilities, in Malaysia," according to a British government accounting. The same British report, by the Butler Committee, said the Joint Intelligence Committee reported new concerns in July 2002 that Khan might be selling the means "to build nuclear warheads."

Blair's government argued with increasing vigor, officials of both countries said, that it was time to confront Pakistan about Khan and stop the operation of his network.

"We disagreed," said a senior U.S. policymaker, who would not permit quotation by name on the dispute between allies. Moving immediately, he said, would have closed opportunities for covert surveillance.

Khan continued moving freely abroad, evading nominal restrictions. On a trip to Beijing, one senior Pakistani diplomat said, Chinese authorities "took me aside, said they knew it would be embarrassing, but A.Q. Khan was in China and bribing people, and they wanted him out." The diplomat said Pakistan confiscated a false passport, but Khan kept traveling.

"They made no attempt to get a handle on his activities abroad," said John Wolf, who was Bush's assistant secretary of state for nonproliferation until June.

Bolton said Bush's advisers "were continually engaged in a trade-off" between stopping the sales of nuclear technology and learning enough about them "so that when we did move we brought down what we could."

"It was a 51-49 call every day we were going through this," he said.

Deliveries to North Korea

As London and Washington tried to keep watch in 2001 and 2002, important parts of the black-market network escaped their view. During that period, authoritative sources in both capitals said, Khan's operation delivered tens of thousands of gas centrifuge parts that brought North Korea to the threshold of unlimited bomb production.

It was that unhappy discovery, made in two stages in July and September 2002, that forced North Korea back onto Bush's agenda when he was trying to keep the world's focus on Iraq.

Until then, North Korea was believed to be a nuclear power with "one or possibly two" weapons and no immediate route to more, according to declassified CIA reports. Its existing arsenal had been built with plutonium from a nuclear power plant. In 1994, Clinton neared the brink of war to prevent North Korea from extracting more plutonium from spent reactor fuel. Instead North Korea agreed to shut down its reactors and leave the spent fuel -- enough for five or six bombs -- under U.N. seal, in return for energy and food aid from the United States, South Korea and Japan.

U.S. intelligence agencies knew North Korea was working to circumvent that agreement by acquiring technology to enrich uranium, the alternative ingredient for a bomb. But as recently as June 2002, a National Intelligence Estimate judged it would be three years or more before the Pyongyang government could assemble gas centrifuges in a small test cascade.

By September, U.S. officials said, the CIA reached the dismaying conclusion that a "production-scale" centrifuge facility was nearly complete. "It was much more advanced then anyone expected," said a White House official who followed the subject closely.

With a supply of enriched uranium, Pyongyang would not need plutonium to build bombs. The CIA's best estimate, Bush administration officials said, was that North Korea could add two weapons to its arsenal each year.

On Oct. 5, 2002, Assistant Secretary of State James A. Kelly returned from a hastily arranged trip to Pyongyang with stunning news. When he confronted the North Koreans about U.S. suspicions, they responded by belligerently acknowledging his claims.

The Bush administration dispatched Kelly to brief allied ambassadors. One of them asked whether Bush would seek U.N. Security Council attention for Pyongyang. Kelly replied, according to a diplomat who was present, "The Security Council is for Iraq." Kelly said through a spokesman he does not remember the remark.

Inheriting 'a Train Wreck'

Behind the scenes, most of the president's national security team saw Kelly's news as confirmation that Bush "inherited a train wreck" from Clinton, said a policymaker who has watched both administrations. They resolved to stop "paying the North Koreans just to show up at meetings," and Bush halted U.S. contributions of food and fuel aid under the Clinton agreement.

"Having been burned once," Falkenrath said, Bush's advisers refused to "start talking about benefits, carrots" for North Korea in exchange for further promises. "They say insanity is to just repeat the same behavior and expect a different outcome," he said.

The president's advisers agreed that North Korea must halt its uranium program but could not agree on steps to compel -- or provide incentives for -- Pyongyang's compliance. For the next six months -- a consuming period from the run-up to war in Iraq to the fall of Baghdad -- Bush largely set North Korea aside. His administration took no further action save to organize ongoing six-nation talks that began in August 2003.

In the same period, North Korea broke the seals on its stored plutonium, expelled U.N. inspectors, restarted its Yongbyon reactor and withdrew from the nuclear Nonproliferation Treaty.

"We had a choice and we played it tough, and so did they, and now we're stuck," said a senior intelligence official.

Bolton defended the record.

"This is quibbling, to say they had two plutonium-based weapons and now they have seven," Bolton replied. "The uranium enrichment capability gives them the ability to produce an unlimited number." That program, he said, began when Clinton sought to normalize relations with North Korea and Madeleine K. Albright, his secretary of state, was "dancing in Pyongyang and watching parades."

Purchases in Iran

The summer of 2002, the season of North Korea's burgeoning threat, brought a parallel development in Iran. There, too, a hidden uranium enrichment program was unveiled. Iran's purchases, however, did not begin on Bush's watch. They began on President Ronald Reagan's, in 1987.

Einhorn, assistant secretary of state for nonproliferation under Clinton and through most of Bush's first year, said in an interview that "we were sniffing on the wrong trail through much of the '90s." Iran misdirected attention to a controversial reactor at Bushehr, when its more dangerous purchases of centrifuge equipment were going to a village called Natanz. Later, in 2003, the International Atomic Energy Agency would discover that Iran's supplier was Khan.

On Aug. 14, 2002, an exiled Iranian opposition group held a news conference in Washington to disclose the Natanz plant.

"The firepower of the U.S. government was directed at -- we were getting ready to go to war," said Falkenrath, who was senior director for proliferation strategy on the National Security Council staff and deputy White House homeland security adviser before leaving government in the spring. "There was stuff going on with Iran and North Korea" in interagency discussions, he said, "but it wasn't as intense as what was happening in Iraq."

In the Oval Office on Oct. 30, 2002, IAEA Director General Mohamed ElBaradei told Bush he had spoken to Iranian leaders and believed they could still be dissuaded from enriching uranium. According to sources with access to written accounts of their meeting, ElBaradei said Iran wanted to talk and offered to help open a quiet channel. Bush demurred.

The president's advisers were at a stalemate on what to do about Iran. One senior participant in the interagency debate, whose shorthand description matched that of many others, said the Defense Department and Vice President Cheney's office "tended toward a 'regime change' view of Iran," while State said "regime change is nice if you can get it at an acceptable price, but you can't."

That argument had begun nine months earlier, when deputy national security adviser Stephen J. Hadley asked the CIA to assess, among other things, the stability of the Iranian government. The agency's report said Iran was evolving toward democracy and that U.S. attempts to undermine the mullahs would cement them in power. Participants in the debate said Deputy Defense Secretary Paul D. Wolfowitz dismissed the report as "one man's opinion."

In a bid for consensus, Hadley supervised preparation of a national security presidential directive to guide Iran policy. Two officials who read the draft said it contained no more than a sentence on nuclear weapons -- calling for U.S. efforts to delay, disrupt and deter Iran's acquisition. Defense officials tried to insert more muscular language, participants said, and Secretary of State Colin L. Powell's representatives proposed incentives -- such as U.S. agreement to Iran's entry into the World Trade Organization -- if Iran changed its behavior in ways that could be verified.

Mutual vetoes by competing camps left those changes unmade and the document unsigned as Bush completes his term.

Twice more after ElBaradei's visit, Tehran signaled interest in discussing its nuclear program. Swiss Ambassador Tim Guldimann arrived in Washington carrying an plan he had discussed with Mohammad Sadegh Kharazi, a nephew of Iranian Foreign Minister Kamal Kharazi and Iran's ambassador to France. The agenda laid out the framework of a "grand bargain." The administration brushed it aside. "We're not interested in any grand bargain," Bolton said.

To avoid "misunderstanding and potential conflict," one official said, the Bush administration did permit secret talks as it prepared to launch two wars on Iran's border. Periodically over 18 months, the two sides discussed their mutual interests in Afghanistan and Iraq. But "instructions were clear" to the U.S. negotiators, a Bush administration policymaker said: "Don't bring up the nukes."

Libya's 'Surrender'

One year later, another Bush administration official met a cargo ship arriving from Tripoli. Robert G. Joseph, senior director for proliferation strategy on the NSC staff, watched pier side as stevedores unloaded 500 tons of technology from the M/V Industrial Challenger and dispatched the contents to the Oak Ridge National Laboratory in Tennessee.

It was Libya's entire nuclear weapons program, bought over a decade for $100 million and change from Khan. On Dec. 19, three months before, Libya had become the first country since 1995 to pull up a nuclear program by its roots -- a striking accomplishment for Bush and Blair.

Explaining that success has become the subject of sharp debate within the administration. Advocates of a hard-line approach to Iran and North Korea argue that Libya's example proves their case. They said isolation, relentless pressure and the U.S. invasion of Baghdad compelled Libyan leader Moammar Gaddafi to give up his program -- and that the United States promised nothing in return. Bush and Cheney, on the campaign trail, adhere to that story line.

Their account begins in March 2003, when Gaddafi's son approached British authorities just before U.S. bombing began in Baghdad, and ends in December, when Gaddafi cut a final deal just after Hussein was pulled from a shallow bunker by U.S. forces.

"There were a lot of things that were clearly operating but to say the deployment of hundreds of thousands of U.S. forces had no impact is silly," a proponent of that analysis said.

Other accounts embrace a wider span of time. Libya suffered crushing economic sanctions in 1992, after the 1988 destruction of Pan Am 103 over Lockerbie, Scotland. Gradual cooperation with U.S. and British investigators in the 1990s suspended the U.N. sanctions. Gaddafi renewed diplomatic relations with London and sought to do so with Washington. Beginning in the summer of 2002, Gaddafi sent intelligence officers to discuss his weapons programs with British intelligence. In March 2003, his son Saif joined the negotiations, and the CIA after that.

Those talks got a final push on Oct. 4, 2003, after investigators received a tip about a German-registered ship bound for Tripoli, the BBC China, with a cargo of thousands of centrifuge components. Authorities diverted the ship to the Italian port of Taranto, they confronted Gaddafi's government and, within days, the Libyan leader allowed British and U.S. experts into Libya.

Flynt Leverett, then director for Middle East affairs on the NSC staff -- now a Brookings Institution fellow who has advised the presidential campaign of Sen. John F. Kerry (D-Mass.) -- said U.S. and British officials offered Libya an "explicit quid pro quo." If Libya relinquished its weapons programs, the United States would lift its sanctions and allow the U.N. sanctions permanently to lapse. That would open the door to lucrative oil deals for both countries. Saif Gaddafi has said in published interviews that his father also received assurances that the United States and Britain would not interfere with his continuation in office.

Bush administration hard-liners, who oppose any such incentives for Iran or North Korea, deny that negotiation was involved.

"It's 'engagement' like we engaged the Japanese on the deck of the Missouri in Tokyo Bay in 1945," said one influential advocate of that view, who declined to be quoted by name. "The only engagement with Libya was the terms of its surrender."

Unanswered Questions

Iran was Khan's first customer, North Korea his second and Libya his undoing. What troubles U.S. and British officials today is the evidence of a fourth customer yet unknown.

One key clue is a ship that never arrived. Not long before Libya's disarmament, scientists in Tripoli placed an order for additional centrifuge parts. Because Khan's network operated through intermediaries, the Libyans do not know who was going to make the components, or where. Investigators in Washington, London and Vienna said they have been unable to learn.

A more disturbing unknown is the source of Libya's small cache of highly enriched uranium.

Most troubling are orders, invoices and manifests found in Khan's overseas records describing shipments that cannot be accounted for by known customers. U.S. and IAEA investigators have several suspects for a "fourth customer" -- officials named Syria, Egypt, Sudan, Saudi Arabia and Kuwait in approximate order of interest -- but no substantial evidence has surfaced.

The Khan network, in many ways, "is al Qaeda all over again," said one U.S. investigator. Bush said in a Sept. 30 debate with Kerry that "the A.Q. Khan network has been brought to justice." The investigator asked, "Does it matter if we get the leadership? Are the cells, manufacturers and middlemen independent? Do we really know who they are? Hard to believe this is the only one out there."

Since his televised confession on Feb. 4 -- and immediate pardon -- Khan has been held in conditions that Pakistani officials liken to "house arrest." Pakistani intelligence agents accept written questions from U.S. or U.N. investigators. They send replies at their discretion. Information obtained elsewhere, Wolf said, makes clear that Khan "is being less than fully candid."

"Khan knows too much about Pakistan's program" for Musharraf to permit unrestricted questioning, said Feroz Khan, a former nuclear adviser to the Pakistani president. "Also, he is a man of tremendous organizing ability and you never know, his services may be required again some day."

The night of Abdul Qadeer Khan's confession, Musharraf summoned editors from all over Pakistan to Islamabad. Speaking in Urdu for a domestic audience, he complained bitterly that "Muslim brothers" in Libya "didn't even ask us before giving us away," according to a translation of the transcript made for The Post.

Facing Musharraf from a semicircle of colleagues, one editor asked whether Pakistan would submit to outside demands -- for compliance with the Nonproliferation Treaty, for U.N. inspectors to see Khan's records and for an impartial inquiry into the army's alleged complicity with Khan.

"Negative to all three of them," Musharraf replied. "We will do no such thing."

Stockpiles in Russia, Pakistan

Libya's disarmament, Khan's exposure and the ongoing war in Iraq -- signature events in Bush's nuclear record -- do not address what intelligence agencies describe as the major source of terrorist risk: "the vulnerability of Russian WMD materials and technology to theft or diversion," as Tenet put it last year.

Half the world's stockpile of plutonium and highly enriched uranium is in Russia. About 600 metric tons are warehoused in some form. Of that quantity, the Department of Energy reported at the end of 2003 that 22 percent is satisfactorily secured with U.S. technical and financial assistance. The department predicted that such "comprehensive" upgrades would cover 26 percent of the stockpile by the end of this year.

Extrapolating from those figures in his first debate with Bush, Kerry said it would take 13 years to secure Russia's bomb ingredients at the current pace.

"The big gorilla in the basement is the material from Russia and Pakistan," said Robert L. Gallucci, dean of the Georgetown School of Foreign Service and a classified consultant to the CIA and Energy Department laboratories. "This is the principal, major national security threat to the United States in the next decade or more. I don't know what's in second place."

Securing the materials is laborious, expensive and dangerous work. Bush decided to let two of the major programs lapse because Russia declined to accept a change in the agreement that would shield U.S. firms from liability for worker safety.

Sen. Pete V. Domenici (R-N.M.), who asked to testify before the Senate Foreign Relations Committee on June 15, noted Bush's emphasis on the "immense threat" of nuclear terrorism and said acidly, "I wonder if he has been advised that liability -- that the liability issue is preventing destruction of enough plutonium for about 10,000 weapons?"

The Bush administration speaks with many voices about securing global stockpiles of nuclear materials. Some of the loudest are skeptical.

"I don't believe that at this point, or for some number of years, there's been a significant risk of a Russian nuclear weapon getting into terrorist hands," Bolton said. "I say that in part because of all the money we've spent . . . but also because the Russians themselves are completely aware that the most likely consequence of losing control of one of their own nuclear weapons is that it will be used in Russia."

Bush has spoken in favor of "cooperative threat reduction programs" funded under 1991 legislation sponsored by Sen. Richard G. Lugar (R-Ind.) and then-Sen. Sam Nunn (D-Ga.). He has also sought to reduce their budgets. His 2005 budget request would cut the Defense Department's efforts to secure foreign nuclear stockpiles by $41 million, or 9 percent. On the other hand, Bush has added substantially to budgets that pay for "decommissioning" old U.S. nuclear weapons. That appears to account for his assertion in the debate with Kerry that he increased spending on nuclear cleanup programs by 35 percent.

Gallucci, who held arms control posts under presidents from Gerald Ford to Clinton, said he finds himself "on the edge of saying really shocking things."

"If tomorrow morning we lost a city, who of us could have said we didn't know how this could happen?" he said. "I haven't felt like this in all the years I've been in government or the nine since I've been [out]. I am -- I don't want to say scared, because that's not what I want to project, but I am deeply concerned for my family and for all Americans."

Researcher Robert Thomason contributed to this report.

In 2002, President Bush vowed to keep the "most destructive weapons" from al Qaeda. John R. Bolton hails Libyan disarmament.Pakistan's Pervez Musharraf, right, forced nuclear scientist Abdul Qadeer Khan to step down.In 2002, James A. Kelly relayed news that North Koreans acknowledged that they could expand their nuclear program.

Iran's facility in Natanz, seen in a satellite image, was the site where much centrifuge equipment was headed. A Pakistani was the supplier.On the campaign trail, Bush has pointed to his administration's work pressuring Libya to give up its weapons program.Libya's dismantled equipment was sent in part to Tennessee, where Pat Galardo stands guard.