y two great loves are physics and desert country," J. Robert Oppenheimer once told a friend. "It's a pity they can't be combined."

Yet those loves would be combined at Los Alamos, where the work of Project Y of the Manhattan Engineering District-the Manhattan Project-showed definitively that knowledge is power. Oppenheimer, a theoretical physicist, was the laboratory's first director. General Leslie R. Groves, who had just finished building the Pentagon, commanded the project for the military. The two were drawn to the remote site in northern New Mexico occupied by the Los Alamos Ranch School, an institution organized, historian Richard Rhodes writes in The Making of the Atomic Bomb, "to invigorate pale scions."

With the Ranch School evicted, Groves set about to invigorate pale scientists. As he described his charge, "We were faced with the necessity of importing a group of highly talented specialists, some of whom would be prima donnas, and of keeping them satisfied with their working and living conditions." That responsibility was a tall order at the time of the Manhattan Project-and so it remains today.

Browne: Los Alamos leader can "take the heat" Photo: Jack Kotz

The Los Alamos Nuclear Laboratory, familiarly known as LANL, covers more than forty-three square miles of mesas and canyons, of pine and juniper forests in the Jemez Mountains. It is spread out among fifty "technical areas," many of them shielded by barbed wire, chain-link fences, guards, and surveillance cameras. Its annual budget is $1.2 billion. It employs 6,800 University of California employees (the university operates the lab for the U.S. Department of Energy) along with "contractor personnel" numbering 2,800. About one-third of the technical staff members are physicists. One-fourth are engineers, one-sixth are chemists and materials scientists, and the rest work in mathematics and computer science, biological science, geoscience, and other disciplines.

Running it all from an office in "TA-3," the Main Technical Area, is the latest successor to the legacy of Groves and Oppenheimer, John Browne Ph.D. '69, whose tenure has so far spanned the past three years. Outgoing U.S. Secretary of Energy Bill Richardson says Browne "has withstood the test of brimstone and fire, quite literally. He has led his laboratory-really more of a city than a laboratory-through charges of espionage, security problems, and the worst fire in the history of Los Alamos. He has been a source of strength to his professional colleagues and his community, and a valued adviser to the Department of Energy."

Last spring, The New York Times offered this headline in profiling him: "Can This Guy Take the Heat?" And it answered the question: "It Sure Looks That Way."

here's not much heat in November's northern New Mexico atmosphere. A day of constant rain and thickening fog puts Los Alamos at a strange remove: You climb and climb up to 7,300 feet, heading toward no visible target, but with the vague sense of being swallowed up by the enveloping mountains. Then you come upon civilization in the high desert.

One of the signs of civilization, on a main street near a supermarket and a strip mall, is the Bradbury Science Museum, operated by LANL. The museum has an array of unusual artifacts: mock-ups of "Little Boy" and "Fat Man," the atomic bombs dropped on Hiroshima and Nagasaki; an exhibit asking "Does Los Alamos glow in the dark?" which encourages visitors to capture various Geiger-counter readings of a camera lens, a red Fiestaware plate, and a green, over-the-door "Exit" sign; the 1939 Einstein letter that urged President Roosevelt to pursue the military implications of the discovery of fission; a video that celebrates "The Town that Never Was"-that is, Los Alamos in wartime.

The most striking item on display is a piece of low technology, a comment book that invites "debate about the role and future of the lab." The book reveals an abiding fact about the Bomb: Just as it's presumed to have the power to be the destroyer of worlds, it has the power equally to define worldviews.

In a spirit of agonized ambivalence, one comment reads, "Even hindsight does not leave a clear or correct choice for the leaders who decided the use of the atomic bomb was necessary. We can not condemn that which occurred. We can only strive to ensure those fateful circumstances do not arise again." A woman writes affectionately of forty-four postwar years together with her husband. In wartime, he had been preparing to be shipped off to the Pacific theater. Today she says, "I probably have my children and grandchildren due to the atomic bomb being dropped on Japan."

The anti-Bomb partisans make their own strong-minded assault. "I have, for over twenty years, worked in the Women's Peace Movement in the U.K. to get rid of all nuclear weapons," goes a comment. "The U.S.A. is such a beautiful country. Is this the best you can do?" In the same spirit, Ed Grothus scrawls this message across a page: "One bomb is too many." Grothus, a local celebrity of sorts, is a former lab employee who now fashions himself a Socrates inspiring questioning of the nuclear culture. Then there are the mysterious statements -perhaps flippant, perhaps profound-like "Bombs rule!" Would that be a benevolent or malevolent rule? And, "Plutonium is forever." Indeed.

Whether or not bombs rule, Los Alamos rules as the government's prime nuclear-weapons research center. If it's no longer "The Town That Never Was," Los Alamos is a town like few others. It's a company town that grew up in World War II and now boasts a huge proportion of Ph.D.s. Even as it projects an aura of newness, it's surrounded by Pueblo Indians, whose presence can be traced back thousands of years, and by a sizable Hispanic population that dates back at least four centuries. One of the lab's critics, Greg Mello, who heads the Los Alamos Study Group, says the economic performance of the area "raises questions about the efficacy of nuclear pork in creating a sustainable society." While New Mexico ranks as having the most federal spending per-capita of any state, it has miserable indicators in areas like childhood poverty and educational achievement, he says. "Statehood feels like an experiment here that didn't quite catch. Our institutions are very weak, and so we are in a very real sense a nuclear colony."

Even as John Browne cites the record of National Merit Scholars produced by Los Alamos High School, he acknowledges the economic disparities that surround the lab. Santa Fe is the seat of state government and draws tourists with its vibrant arts scene; Taos is a prime skiing area; and LANL is the Ph.D. magnet. Beyond that, "the economy is basically a rural agrarian economy," according to Browne. He says a University of New Mexico study found that LANL accounts for 40 percent of the economy of northern New Mexico. About half of the LANL workforce lives outside Los Alamos, he says, and that demographic fact ties the lab to the region around it. And he mentions the Los Alamos National Laboratory Foundation, a nonprofit that focuses its resources on education regionally. Through their foundation, lab workers support scholarships for students, volunteer to wire schools for computer connections, and contribute teaching time.

Browne says the character of the area has infused his thinking. "For example, the Indians have a lot of expressions where they look beyond their own generation or even their children to generations far into the future." That far-afield view creates a sense of environmental stewardship, he says. And he wants the lab to be a good neighbor, concerned not just with controlling hazardous products of its work but also with "sitting down face-to face with people and listening to them talk about their issues." One close observer of LANL is George Keyworth Ph.D. '68, who joined Los Alamos right after graduate school. He says Browne has a set of "rare attributes" that serve him well in "setting direction for the world's greatest laboratory." According to Keyworth, "John knows a good piece of experimental research when he sees it; he can recognize it instinctively. And he has very good judgment, very good taste in people. He didn't get the job because he's a bureaucrat. He's a first-class scientist respected by other first-class scientists. But in dealing with a couple of real crises, he has been absolutely extraordinary."

Keyworth came to know Browne when they were working toward their Ph.D.s. While a graduate student at Duke, Browne-who as a physics major at Drexel University had ranked first in his class-was a standout. Keyworth says, "I always thought he was a guy with a steady hand. Graduate students tend to be creative and dedicated, but they're not always a mature and responsible lot. Among his peers, John was the most mature and the most responsible." Now working nearby as a consultant, Keyworth became head of the physics division at Los Alamos in 1977. In 1979, he persuaded Browne to join Los Alamos as head of a nuclear physics research group. In 1981, when be became science adviser to President Reagan, Keyworth supported Browne to be his successor as physics division leader.

Control central: the Neutron Source Center, which Browne headed before becoming LANL director Photo: Jack Kotz

Browne, before he was tapped as lab director, headed the Los Alamos Neutron Source Center (LANSCE). LANSCE is an 800-million-electron-volt proton accelerator that produces neutrons for research in materials science, nuclear physics, and biology. It draws hundreds of researchers, faculty and students alike, from U.S. universities.

For a year after earning his Ph.D., Browne taught physics at Duke. He said he might have persisted in university teaching, but the profession was "just bone-dry" in terms of opportunities. He taught introductory physics to students, many of them pre-meds, and induced many of them to come to optional sessions where he'd tackle problem sets. "I always felt I was good at explaining how to solve problems," he says. It's a knack that has served him well.

Between Duke and Los Alamos, Browne was part of the experimental physics division at another national lab, California's Lawrence Livermore, where his job interview was with Edward Teller. Teller, one of the designers of the original atomic bomb and a refugee from Hitler's Germany, once told historian Richard Rhodes that deflecting his attention from pure physics to weapons work "was not an easy matter. And for quite a time I did not make up my mind." He wanted to know if Browne would consider, in the future, straddling the lines between pure research and weapons-related problems. "Frankly, I started to give him a circuitous answer," Browne recalls. "And he basically came back and said, 'No, this is a really simple question: Either you will or you won't.

If you don't want to, that's fine, but I think you ought to go do something somewhere else. If you're willing to, then we need you, because we need people who can walk in both worlds.' So I said, 'Yes, I can do it.' And he said, 'Well, the day will come when I'll ask you to help.' "And sure enough, about two years after I joined Lawrence Livermore, he called me and said, 'Come to my office immediately, I have a problem.' Well, I got there, and there were ten other young people. There was an interesting defense problem, a very, very important one. And he said to me, 'I know you know something about this problem. Go to the blackboard and tell us all what you know.'"

In Browne's view, the culture of the lab is still shaped by a core principle articulated by Oppenheimer-that peace is best assured through the deterrent power of nuclear weapons. "The mission that we have for the country is to enhance global security," he says. "And I use those words carefully, global security. First of all, nuclear weapons were created during World War II to meet a particular challenge. During the Cold War, nuclear deterrence played a strong role in all of our interactions with the Soviet Union. Now we're past the Cold War. And one of the questions that the country is having to work through, and the rest of the world is having to work through, is whether there is a role for nuclear weapons to deter global conflict. When you no longer have this bipolar world, the U.S. and the Soviet Union, is there a credible role for nuclear weapons?

"I think if you did a poll, almost everyone here would favor arms reductions, if they're done in a balanced and intelligent way. Regardless of the number of nuclear weapons, we have a responsibility to make sure they are safe and reliable. Because the reliability is part of the nuclear deterrent. If your enemy believes your weapons aren't reliable, they're no longer a deterrent."

n this gray day in New Mexico, Browne is dressed casually in a white turtleneck shirt. He's universally described as generous and affable-even by a contract worker, randomly encountered, who is targeting the lab for a lawsuit but who speaks of its director in admiring terms. Hardly the cloistered administrator, he revels in the exuberant outdoor routine characteristic of northern New Mexico's residents: His repertoire includes skiing, jogging, mountain biking, hiking, and playing tennis.

To reach Browne's office, with the accompaniment of an official escort, you go through a security check at a guard's station that displays a sign reading "Think Security." In the light of the notorious Wen Ho Lee case, that sign can be considered a show of either institutional alertness or institutional irony.

In September, Lee, a former Los Alamos scientist, pleaded guilty to a single felony count of mishandling classified data; he had been indicted on fifty-nine counts. He was then released, after having spent nine months in solitary confinement. Reportedly, he had copied some 800 megabytes of nuclear information, the equivalent of more than 400,000 pages. A federal judge in Albuquerque said the federal government's actions in the matter had embarrassed the nation. One commentator called it a case that had gone from the pursuit of "the spy of the century" to "the incredible shrinking prosecution."

The Wen Ho Lee case grew out of a context of security scares. A congressional report released in the spring of 1999 declared that China "has stolen design information on the United States' most advanced thermonuclear weapons," that China's developing nuclear arsenal "will exploit elements of stolen U.S. design information," and that Chinese penetration of national weapons laboratories-Los Alamos prominently included-"spans at least the past several decades and almost certainly continues today." It charged that "counterintelligence programs at the national weapons laboratories today fail to meet even minimal standards." The report came from a committee in the House of Representatives chaired by California Republican Christopher Cox. Cox's committee had been investigating whether contributions to the 1996 Clinton reelection campaign played a role in helping sensitive satellite technology find its way to China.

In June 1999, a second report was issued, and it struck a similarly critical tone. Originating in the President's Foreign Intelligence Advisory Board, which is chaired by former Senator Warren Rudman, it was titled "Science at Its Best, Security at Its Worst." The report found in the Department of Energy and the weapons laboratories "a deeply rooted culture of low regard for and, at times, hostility to security issues." Its "bottom line" conclusion was that the national laboratories represent "the best of America's scientific talent and achievement," but that they have been responsible for "the worst security record on secrecy" known to panel members. "Organizational disarray, managerial neglect, and a culture of arrogance-both at DOE headquarters and the labs themselves-conspired to create an espionage scandal waiting to happen."

Journalistic exuberance fed the fears. Extensively citing the Energy Department's director of intelligence, whose views evidently had shaped the Cox committee findings, The New York Times ran a front-page report. Its provocative headline declared that "China Stole Nuclear Secrets for Bombs, U.S. Aides Say." The article alleged that China had made "a leap in the development of nuclear weapons: the miniaturization of its bombs--accelerated by the theft of American nuclear secrets from Los Alamos."

Supposedly, China had acquired data on a highly advanced warhead design called the W-88, a miniaturized warhead originally developed at Los Alamos. But in a lengthy, somewhat self-critical editorial analysis this fall, The Times acknowledged that "classified information on the critical American W-88 warhead existed in 546 government and industry offices other than Los Alamos." The editors went on to admit that the newspaper had "too quickly accepted the government's theory that espionage was the main reason for Chinese nuclear advances."

Browne says the harsh verdicts on the lab's security-mindedness weren't fair. "Did we have issues that we need to fix? Sure, that's true. There were some weaknesses. But does it mean the entire institution is corrupt as a result of one event? You have to put it in the context of fifty-plus years of existence." Much of the criticism, he points out, targets the Department of Energy's confusing organizational structure. The issue of Chinese missile technology, as he puts it delicately, "is a little bit challenging for me to talk about in an open sense." He does speculate that China would like to have more advanced missile technology, and so be able to strengthen its deterrent. But he's circumspect about possible penetration of the national labs: "I think it's an open question as to whether any espionage occurred."

A report in a summer 1999 issue of The Nation earned its own provocative headline: "The Spy Who Wasn't." According to the magazine, there is "little evidence to suggest the Chinese have acquired the know-how necessary to construct the W-88," and "there are solid reasons to believe they haven't. The most important is that they haven't built one." China's aging arsenal of some two dozen single-warhead, liquid-fueled ICBMs, compared with an 8,000-warhead U.S. arsenal, "closely resembles U.S. warhead technology from the Fifties," The Nation said.

For his part, Browne says that China's moving to a modern nuclear stockpile akin to that of the United States "is not in the cards." Browne, who says he never knew Lee personally, says, "I don't think any of us understand why he did what he did." But he adds that it's too easy to presume that the copied files were available through open sources. "All the words in the dictionary are unclassified. It's how you assemble them into a story that determines whether the story is classified. If you take that analogy over to Dr. Lee, I would say, my personal opinion is that Dr. Lee's actions were very serious." He takes a long pause. "I've tried to be pretty clear in my statements in the past that clearly, in my personal opinion, what he did was one of the worst security violations in Los Alamos' history."

Motivations aside, Lee's treatment by federal authorities troubled many at LANL, Browne says. "What you would find if you'd talk to a lot of laboratory scientists is that they didn't know the details of what his security transgressions were. But regardless of what they were, a lot of them felt that the treatment didn't fit, that it was too harsh. They would say he should have been fired, and he was fired. But does that mean he should have been put in solitary confinement and in shackles?"

A sign of the morale-boosting challenges that LANL faces came with a talk at Duke this fall. The speaker was L. Ling-chi Wang, director of Asian-American Studies at the University of California at Berkeley. "The only reason why he was subjected to nine months of Gestapo-type investigations by the FBI and CIA," he said of Lee, "the only reason why he was placed in solitary confinement for nine months without a trial, was solely on account of his race." Lee, in his words, had become "a classic victim of racial profiling, convenient scapegoating, and selective prosecution." Wang called the indictment a "political decision" that produced a "political kidnapping"; the intent, he said, was to insulate Democrats from the partisan findings of the Cox committee about supposed Chinese espionage and security lapses. He suggested that Asian Americans might want to boycott job opportunities at the national labs, including Los Alamos.

Back at LANL, Asian-American scientists were "very concerned" about a possible "backlash toward them by the U.S. government," Browne says. The case brought into high relief concerns about discrimination on the basis of ethnicity and "glass ceilings," especially regarding promotion into management. He's had meetings with the concerned colleagues, and has brought in outside speakers on the subjects of diversity and racial profiling. "It's only recently that I can see some beginnings of a turnaround of morale," he says.

"The real issue that affects morale is the question, Does the government trust the scientists anymore at this laboratory? And vice-versa: Do our scientists trust the government to treat them fairly? If someone makes a mistake, they expect to have some penalty for the mistake. They don't expect to be jailed and shackled for a mistake. The fear in a lot of people's minds who work with classified matter is, 'If I make a mistake, I'm going to be handed my head.' We have to rebuild that trust, in both directions. The government can do as much damage to national security by overreacting to events as they can going the other direction and ignoring serious security problems. Achieving that right balance is critical for national security, and not just at Los Alamos."

That delicate balance may be thrown off by the use of polygraphs mandated by the Department of Energy. Lab scientists see the sense of polygraphing as a follow-up to suspicious activities, Browne says. "What they object to is the use of polygraphs as a screening tool for loyalty." The CIA's Aldrich Ames-convicted of espionage, unlike Wen Ho Lee-managed to fool the technology. The National Academy of Sciences studied the polygraph, and the findings were "certainly not a ringing endorsement of polygraphs, particularly for screening a large number of people," he says. "I've taken a polygraph; I said I'd be the first one in the lab. And it is an uncomfortable situation, because you're wired up to a serious of monitors looking at very sensitive emotional factors. Even the experts who are strongly supportive of the polygraph will tell you that it is not a lie detector," but rather an indicator of physiological reactions like changes in blood pressures or breathing rates.

"The question that our scientists ask, which I think is a very legitimate question, is if you can't resolve my physiological responses, will you destroy my twenty- or thirty-year career? The answer from the people in the security world is that those results alone aren't enough to pull someone's security clearance. And it's back to the same issue: Why don't people trust us?"

Mutual trust wasn't promoted by last spring's less sweeping security scandal-the misplacement of two computer hard drives. Reportedly, those hard drives contained data used by the government's Nuclear Emergency Search Team, or NEST, which is responsible for finding and disabling any nuclear bomb that might be planted on American soil. They later reappeared, mysteriously, behind a copying machine at the laboratory.

Browne points out that LANL manages some six million classified documents. With the end of the Cold War, he says, the government relaxed its rules on tracking documents by tagging them with bar codes. At the same time, as the task of creating and storing documents shifted to desktop computers, central computer systems, and centralized control, came to lose their hold. The result, he says, was a lessening of accountability across the government. Now, the bar-coding regimen has returned.

ANL's morale issues transcend the recent security controversies. Browne says the amount of pure research supported at the lab is too little. Traditionally, he says, something like 20 percent of the lab's work was devoted to "advanced, really advanced research, looking five to fifteen years out." Now the figure is closer to 10 percent -a reflection of "the government's near-sightedness with respect to being driven by near-term agendas." Pure research, of course, can find its way into applications. He gives an example of a LANL project on encryption. The project employs quantum mechanics and signal processing to determine if encoded information is being intercepted. "That's a fundamental physics idea that only comes by having really bright people at our laboratory who are at the forefront. And yet the impact both on national security and on the economy could be tremendous."

For years, about three-quarters of LANL's budget has been earmarked for defense. Browne says over the next decade, it's likely that the lab will see at least a slight shift toward civilian research. But defense work can inform the civilian sector, he says. He talks about a study into how pathogens spread through a society-engaging both a "national-security issue" and "a fundamental scientific problem, perhaps involving DNA sequencing and computational modeling." He also mentions a sophisticated transportation simulation that models not just traffic patterns, but also the behavior of drivers in particular circumstances. It's an outgrowth of a project that models the movement of military equipment on the battlefield.

Critics question the caliber of LANL's research program. The Los Alamos Study Group's Greg Mello says the lab has "fallen behind its university peers in the quality of the science that happens there." In more nuanced terms, Duke historian Alex Roland Ph.D. '74 says that universities reward scientists with the most prestige, and industry rewards them with the most money. There are qualifications to such a formula, he adds, depending on fields of investigation, a particular research agenda, and the availability of equipment. And he says the national laboratories have given rise to "very distinguished work." But the perception, "however unfair, is that they are the least distinguished in the hierarchy."

Browne has a different point of view: "Los Alamos scientists and engineers are very active in publishing the results of their research, as evidenced by the number of publications per year and citation indices." He says LANL employees are members of the National Academies of Sciences and Engineering. They are active in such professional organizations as the American Physical Society and the American Chemical Society, as well as the American Association for the Advancement of Science and the American Academy of Arts and Sciences. And many have been elected "Fellows" of those organizations. One Nobel Laureate, Fred Reines, discoverer of the neutrino, did his seminal work at the lab, Browne says. "Remember that the tradition of Los Alamos is built on Oppenheimer, Fermi, Teller, von Neumann, Szilard, and so forth, and so excellence in science is paramount in our culture."

Beyond security and recruitment worries, Browne has had to be concerned about excellence in crisis management. What he calls his most severe trial by fire began in early May as a prescribed burn in the Bandelier National Monument, just south of Los Alamos. Within a couple of days, winds had pushed the fire out of control; it jumped into Los Alamos Canyon, forcing the evacuation of about 18,000 residents of Los Alamos and nearby White Rock, where Browne lives. The fire shut down the lab for two weeks. Of the more than 400 homes destroyed, many belonged to lab employees. Browne says the community was fortunate that there was no loss of life. He has praise for the heroics of local firefighters and those brought in from elsewhere, for the "outpouring of support" locally, as well as for financial-recovery assistance from the federal government and the University of California. The university, he notes, brought in victims of the Oakland Hills fire of several years ago. They counseled Los Alamos' fire victims about the process they could expect to go through. The lab itself had wrestled with wildfires dating back to 1977 and as recently as 1995. It had worked to clear brush from some of its property, and had gone through relevant training exercises. "So we actually felt prepared for the emergency," Browne says. Still, he acknowledges, "we were concerned."

"At one point, the winds were fifty miles an hour, and the fire was burning really close to some of our nuclear-materials facilities. All the material was locked down in ways that it was not immediately threatened by the fire; there were several layers of fire resistance. The fire department did an incredible job of defending all of our buildings. If one of those buildings had burned to the ground, it would have been a serious event." While the fire touched 30 percent of the lab's forty-three square miles of property, none of the lab's permanent buildings was damaged.

"You're dealing with forces of nature that you really can't control," Browne says. "I've never really seen a wildfire up close like that. It's very frightening to see a tree explode and to see flames leap a mile away and to catch something on fire a mile away. It's very hard to stop that kind of fire once it gets going, when you have fifty-mile-an-hour winds. A hundred-foot wall of flame is a pretty impressive thing to see. It's very

One consequence of the fire was concern that radiation levels would go up. The lab's own monitoring equipment, plus sampling by state and federal environmental officials, found "no serious issues of radiation leaving the laboratory site," Browne says. A slight increase in radiation levels, he says, can be attributed to burning trees: A fire releases trapped radiation deposits, whether from naturally occurring cosmic rays or from nuclear testing in the Fifties.

ome of the security-oriented examinations of the lab have questioned another legacy of the earliest nuclear work- the fact that LANL is run for the Department of Energy by the University of California. Such a dual structure invites a clash of cultures, critics say. Browne, though, sees the academic affiliation as a mark of scientific credibility. The university link "also provides intellectual freedom for our scientists to speak out on technical matters even if they disagree with U.S. 'official' positions," he says. Those scientists, and others, have had a lot to say about "Stockpile Stewardship," the label attached to the program for keeping nuclear weapons safe and reliable. Stockpile Stewardship is at the heart of the lab's post-Cold War mission.

The United States has not designed or produced a new nuclear weapon in well over a decade, and it has been mothballing or retiring much of the capability to do so. The last nuclear explosion in the United States was triggered at the Nevada Test Site in 1992. As an article in Government Executive put it, strategic thinkers now have to wrestle with a fundamental question: "Can the United States really maintain a credible and safe nuclear deterrent without the benefit of new designs, weapons production, or nuclear testing?"

"The answer is, 'yes,'" Browne responds. "But it's a really challenging scientific problem. Our stockpile was designed basically to turn over every ten or fifteen years. We now have weapons in the stockpile that are twenty-five or thirty-five years old. And as the weapons age, the materials that they're made of age. What does that mean for the performance of nuclear weapons?" Employing an image popular with nuclear experts, Browne compares an aging nuclear weapon, with its radioactive materials, high explosives, and metal components, to a car that sits in the sun for years. Over time, the dashboard will crack and the upholstery will become brittle. But it's hard to figure out when cosmetic concerns point to a dangerous chain of events.

Some are skeptical of testing by simulation, saying it runs counter to a scientific method that moves from hypothesis to experiment. An article in Mechanical Engineering notes that weapons scientists are having to rely on "huge computers and advanced visualization software to test virtual models of a size that could barely be imagined only a few years ago." But it quotes a LANL physicist as observing, "The real fear in any complicated calculation is that everything runs well on the computer, the results look reasonable, and the answer is wrong." Another scientist, cited in Government Executive, compares the simulation requirements to the moon shot, "because we're requiring increases in computing speed which have never been seen since the invention of the microprocessor."

In late November, a New York Times article quoted several skeptical scientists at Los Alamos. A senior designer of nuclear weaponry declared that a stewardship program with no testing is "a religious exercise, not science." The article noted that in an annual "certification" process, Browne has to make an official pronouncement on the aging stockpile. He continues to certify it as safe and reliable.

Browne says scientists regularly cut up old nuclear weapons to evaluate what's going on inside. And while physical tests may have a scientific allure, he says, "You have to remember that the United States has a thousand nuclear tests behind it. The data are still there to compare your computational models against. On top of that, we're doing sophisticated experiments that are meant to validate those models. And by the way, tests don't always give you every last piece of information: It's complicated to do them, they're very expensive, and you've got to get all the information in a fraction of a microsecond."

LANL's post-Cold War role extends to nuclear nonproliferation efforts. The lab builds advanced sensors that can detect nuclear efforts, and provides technology to help Russia guard against nuclear thefts. It trains the International Atomic Energy inspectors who guard against the diversion of nuclear material to military purposes.

It also does some research for ballistic missile defense, including mechanisms to destroy incoming warheads and sensors to detect the warheads in space. One analyst, Duke's Alex Roland, calls the project a "boondoggle" that wouldn't work, that would inspire other nations to build up their nuclear arsenals in order to overcome it, and that would only address the "least likely attack" against the United States. Browne says, "If a ballistic missile defense system is 30 percent effective, the offense overwhelms it. If the ballistic missile defense system is 90 percent effective, then it becomes a much different scenario. History is filled with this see-saw situation between the offense and defense."

Missile defense has been focused on the mid-course or "exospheric" intercept, "and this is tough because the offense can use decoys that look like warheads," says Browne. "If it becomes possible to intercept missile in their 'boost phase' before they go exospheric, then the defense has a big advantage. But the time lines are short. Ballistic missile defense needs a ground- or space-based fast interceptor to reach things in boost phase."

Browne headed the Los Alamos efforts in ballistic missile defense for five years beginning in 1991. During that period, his team worked on advanced lasers and particle beams in a precursor to today's program, the "Star Wars" initiative, which was meant to defeat Soviet missiles-and whose advocates included Edward Teller and George Keyworth. Now, the Bush administration seems intent on accelerating the missile-defense effort.

oland says Americans remain "uncomfortable" with nuclear weapons. After all, "that's how the Cold War worked; people were uncomfortable, and that was better than the alternative." Presidents dating back to Jimmy Carter have spoken of the national goal of eliminating nuclear weapons. In Roland's view, though, there's something disingenuous about that public rhetoric. "An argument could be made-in fact, I argue this-that nuclear weapons got us through the Cold War and are the primary reason why we never had World War III, which would have been devastating." By his estimate, there are "a hundred million fewer casualties from war than there would have been if we hadn't had nuclear weapons."

It's pretty certain that such an estimate wouldn't go down well with the Los Alamos Study Group, based about thirty miles away from LANL in Santa Fe. It works from an office just blocks from where a plaque commemorates the "check-in point for the military men and women who worked on the top-secret Manhattan Project at Los Alamos." The organization began in 1989 with the idea, as its literature puts it, that "the unprecedented opportunity for nuclear disarmament brought by the end of the Cold War could not be realized without sustained public pressure." In 1997, nine of its members were arrested for criminal trespassing; they were handing out anti-nuclear leaflets at the Bradbury Museum, where for a time they had been granted "alternative exhibit space." They successfully sued LANL on free-speech grounds.

Among those arrested was Greg Mello, the organization's director, whose father was superintendent of construction for some of the buildings of the Lawrence Livermore national laboratory. In his view, the only "legal deterrent" is a conventional-weapons deterrent, nuclear weapons largely created the Cold War, and the Cold War was sustained by "the institutions which found it in their interest to promote nuclear arsenals." Mello admits that anxiety over nuclear weapons may be "receding from public consciousness." He says activism is hindered by a loss of faith in public participation, with the consequence that citizens are retreating more and more into their private concerns.

Mello says he's "never been more negative about the state of openness at the laboratory." Browne, while pointing out that the Study Group has a "stated interest" in the lab's abandoning its prime national-security mission, says he has had discussions with its leadership. He also says he invited them to meet with the new head of the National Nuclear Security Administration during his first official visit. "We do have a policy of openness," he says. "We regularly participate in public meetings regarding the environmental, safety, and health aspects of our research and development."

Another Santa Fe-based group, Concerned Citizens for Nuclear Safety, has successfully sued LANL for violations of the federal Clean Air Act regulating levels of radioactive air emissions. Concerned Citizens got its start in 1988 over the issue of transporting nuclear waste from Los Alamos to the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico. Joni Arends, waste programs director for the group, was a student at nearby St. John's College, which is well known for its Great Books education. As she recalls her involvement, "Some friends and I got together and asked, 'What would Socrates do in this situation?' He'd start a dialogue." Some of that dialogue was among neighbors en route to the proposed waste site, many of whom, Arends says, were persuaded to post anti-WIPP signs on their property. Some was in the courts. According to Arends, lawsuits postponed the opening of WIPP and enhanced regulatory oversight. But the area around LANL has "borne a heavy burden" in damage to the environment, she says. A 1996 story in Outside magazine referred to "at least 1,000 hazardous sites on the LANL grounds." During the Manhattan Project and well into the 1950s, the story said, "technicians routinely piped cesium, plutonium, and other radioactive waste into the surrounding canyons. No one at the lab bothered to maintain records of the burial sites, and their precise locations are in some cases still unknown."

Browne says, "The country has a lot bigger cleanup job from the Cold War than it does from Los Alamos alone. Having said that, we're monitoring more and more of our site, and off our site as well, to understand the effects of what was done here. When I was a kid, frankly, people didn't understand a lot about radioactive materials and storage. What we're now trying to do is to evaluate every site that we have, and then to do an assessment of what it would take to clean that site up."

Last spring's wildfire brought site-specific concerns into high relief. A strange combination-buried hazardous materials, canyons denuded of trees, a floor of pine needles so "vitrified" by the intense flames that they would absorb nothing, and strong seasonal rainfalls-could have brought a noxious runoff into the Rio Grande. Browne says officials removed or blocked in the hazardous material.

Before the fire threatened to overtake the lab, LANL saw its largest-ever anti-nuclear demonstration. That came in the summer of 1999, which had begun with the allegations of espionage. A couple of hundred protestors, some of whom were arrested as they moved onto LANL property, marked the Hiroshima and Nagasaki anniversaries. Among the speakers was Martin Sheen, who dedicated his protest to J. Robert Oppenheimer. The actor, as quoted in The Bulletin of the Atomic Scientists, said of the lab's first director, "I'm quite sure that, if he were alive today, he'd be leading this march." Browne wouldn't be so quick to imagine Oppenheimer on the protest line. But he says he doesn't mind it when LANL finds itself the target of activism. "Sometimes what I tell them is that they can demonstrate against us because the work we've done here has helped protect their freedom. They don't buy it. But I believe it."