You burst into the room. Sitting on a chair, blindfolded, his hands tied behind his back, is your prisoner. The room is dark, except for a lonely naked bulb hanging from the ceiling. He is sweating. He is afraid.

"Tell me where it is!" you scream. "Now!" You know there is little time left. Somewhere in your city, a time bomb is ticking. Whether it spits serin into the air, uranium into the water or atomic fire into the heavens, you do not know.

He does. But he is not talking. Involuntarily, you raise your hand as if to strike. What you are about to do violates the law and your conscience. And yet...

In peacetime, torture ranks next to murder as a primal sin. But during war, the debate begins over whether this evil can ever be justified to combat the seemingly greater evil of the enemy. Harvard law Professor Alan Dershowitz has said torture should be legalized.

In early October, the U.S. Senate voted 90-9 to ban it. Although Secretary of State Condoleezza Rice and President Bush have both recently asserted that "We do not torture," five U.S. Army Rangers were charged in November for punching and kicking detainees in Iraq, secret U.S. prisons have caused anxiety in Europe, and Vice President Dick Cheney has battled to win the CIA an exemption from the torture ban. As late as December, the U.S. House of Representatives stood poised to defeat the White House.

Few of us will ever be asked to torture. But, indirectly, all of us have to make a choice: to support, as citizens, those politicians who back torture, or those who seek its prohibition.

The decision of an individual to support, or reject, torture seems at first to be a purely moral question. But what would be the long-term consequences to society if we were to make this radical break with the past?

One cannot do experiments with societies, or predict the future, but, it turns out, one can attempt to address this issue using the cold, hard tools of mathematics and logic. This story begins in 1963.

The United States and the Soviet Union are on the perpetual brink of war, balanced like two sides of an equation. On the American side are "game theorists" like Thomas Schelling, recently awarded the Nobel Prize for his work on the strategy of conflict. On the Soviet side, there is the solitary mathematical psychologist Vladimir Lefebvre.

Just as mathematics could be used to describe logical reasoning, Lefebvre saw that mathematics could be used to describe ethical reasoning. If something was good -- for example, "church," "democracy," "prosperity," "kindness" -- it had value "1."

If something was evil -- "earthquake," "famine," "military defeat," "murder" -- it had value "0." But rarely were ethical situations so simple. For instance, "killing" is bad (0) but protecting one's country is good (1) -- so is war 1 or 0?

Lefebvre saw that, at the crudest level, there were essentially two types of ethical systems. Those that held that employing evil means to attain just ends was good, and those that saw that employing evil means to attain good ends was wrong.

There were also, crudely put, two types of relations between individuals: those entailing compromise (or cooperation) and those entailing confrontation.

Of course, evil people rarely see themselves as evil. So Lefebvre had to incorporate in his model of human nature the capacity of human beings to judge -- correctly or incorrectly -- the goodness or evil of their own acts, and to reflect upon their own judgments, and others'. "Reflexive Theory" was born.

It quickly became a paradigm within the Soviet defense establishment, with the publication of books such as "Mathematics and Armed Conflict." Nothing like it was known in the West.

With very simple assumptions -- for instance, that an individual who correctly sees his actions to be good when they are good, and evil if they are evil, is more highly regarded by society than an individual who incorrectly sees himself -- Lefebvre showed that in a society that accepted the compromise of good with evil, individuals would more often seek the path of confrontation with each other.

Lefebvre's insights were called upon by the State Department during negotiations with Mikhail Gorbachev in Reykjavik, Iceland. (And perhaps Lefebvre's model could be re-enlisted to help U.S. officials understand and negotiate with Arab and Muslim heads of state, who must also negotiate with their people.)

In support of Lefebvre's revolutionary new theory, a survey of Soviet émigrés and Americans was conducted in the 1970s. They were asked questions like, "Should a doctor conceal from a patient that he has cancer in order to diminish his suffering?" Overwhelmingly, the Americans would say no, and overwhelmingly, the Soviets yes. The Soviets accepted the compromise of good with evil; the Americans rejected it.

What does this mean? If Americans begin to accept the use of torture, American society might turn into a society of individuals in conflict.

Not uniformly, thanks to something called free will, but generally, with harmful consequences for society: Imagine two roads, with a stream of cars moving along each one. Each driver wants to reach his destination as quickly as possible; on occasion, drivers will impede each other.

On the first road, drivers rise in their own, and in other drivers', estimation if they yield. Drivers on the second road lose face when they yield. It is clear that traffic will move faster on the first road than on the second.

It can be argued that repressive states like Saudi Arabia, which bred most of the Sept. 11 hijackers, are on the second road. If the United States moved to accept torture, it could veer toward the second road, too -- the road of the Soviet Union.

And we know where that road ends. The Soviet Union no longer exists.

The prosecution of Saddam Hussein and his co-defendants is off to a rocky start. As of last week, the trial has been adjourned twice after only a day and a half of proceedings; two of the defense lawyers have been murdered, perhaps by Iraqi security agents; and Hussein has showered the judges with contempt and challenged the legitimacy of the tribunal.

Can the trial in fact succeed? That depends on what we think are its goals.

The principal rationale for criminal justice is retribution--to punish those who have harmed others and violated society's norms. But retribution--or revenge--could be achieved without courts and due process. Trials also ordinarily produce reliable determinations of guilt or innocence, but few people, either inside or outside Iraq, have genuine doubts about Hussein's guilt.

The success of the Hussein trial, then, should be judged by whether it can also accomplish any of the broader goals that criminal prosecutions can serve in societies that have experienced widespread atrocities:

1) Providing justice for victims and documenting history. Trials enable victims to confront their abusers, a psychologically important step in the social re-integration of victimized groups. Trials also generate an authoritative record of the crimes committed by a previous regime. This can compel other groups in society--including perpetrators--to acknowledge that abuses occurred and can refute subsequent attempts at historical revisionism. This is today viewed as one of the important legacies of the Nuremberg trials.

The Hussein trial could provide a forum for victims, but only if the tribunal is allowed to address the full range of atrocities perpetrated by his regime. At this point, Hussein is being tried only for crimes committed in connection with a single episode--the killing and torture of residents of the village of Dujail after an assassination attempt on Hussein in 1982. Iraqi prosecutors have said that, after the Dujail case, they will pursue other cases involving the killings of tens of thousands of Shiites and Kurds.

A full airing of the vast tableau of Hussein's crimes, however, could take years; the trial of former Balkan strongman Slobodan Milosevic on crimes of comparable scope before the Yugoslavia War Crimes Tribunal in The Hague has been underway for almost four years. Such a timeline is unlikely to satisfy Iraqi street protesters demanding a swift trial and hanging of Hussein. Prime Minister Ibrahim Jafari's declaration that the Hussein trial "is not a research project" suggests the Iraqi government may feel pressure to sacrifice the goal of giving Hussein's victims a chance to record the atrocities they suffered in the interests of swift retribution.

2) Contributing to peace and reconciliation. Particularly in societies emerging from ethnic or sectarian conflicts, criminal trials individualize responsibility for abuses. They thus allow victims of atrocities to move beyond collective condemnation of the ethnic or religious groups from which their abusers came, enabling once-divided groups to begin to reconcile.

But the Hussein trial seems more likely to inflame sectarian tensions than to soothe them, at least in the short term. It gives Hussein a platform from which to challenge the Shiite-dominated government and to rally Sunni insurgents. Shiites and Kurds, frustrated by delays in having Hussein face the justice they believe he deserves, may escalate attacks against Sunni or Baathist targets. The net result may be a spiraling pattern of vigilantism and counter-vigilantism.

3) Promoting the rule of law. Subjecting a former dictator to a court of law, rather than a firing squad, can commit a transitional regime to due process and the rule of law. But early indications do not give hope that the Hussein trial will promote this goal. Last-minute legal changes--such as the elimination of the right of defendants to represent themselves--have been made for political, rather than legal, reasons. Tribunal officials have been selectively targeted for dismissal by the de-Baathification Commission headed by Ahmad Chalabi.

Moreover, Iraq's president announced in September that he had learned from one of the tribunal's investigating judges that Hussein had confessed to ordering executions during the notorious Anfal campaign, raising further questions about the judicial independence of the tribunal. Even the decision to try Hussein for the Dujail killings before the completion of investigations of more serious atrocities appears to be politically motivated. The government hopes to demoralize Hussein loyalists by securing a swift conviction on the easiest charges to prove.

Even under the best of circumstances, the Hussein trial could not possibly accomplish all three of these goals simultaneously. Hussein's crimes are so numerous that no trial can produce both a full historical accounting and swift justice. Iraq may be better served by establishing a truth commission to write a comprehensive history of the abuses of the Hussein era. Efforts to manage the trial to promote political stability in Iraq are unlikely to succeed and will only reflect a continuation of the Hussein-era tradition of executive branch manipulation of the courts. Addressing Sunni grievances, protecting minority rights and sharing Iraq's wealth is the way to promote reconciliation.

The best hope for the Hussein trial to be meaningful is for the Iraqi government to accord him full due-process rights and to refrain from further interference and manipulation. If the Iraqi government accepts the constraints of the rule of law, the Hussein trial can teach Iraq the valuable lesson that the state may punish citizens, even one as detested as Hussein, solely on the basis of laws impartially applied, not on the whims or caprice of the ruler.

This week President Bush will seek to focus the nation's attention on border security and immigration reform. But the president's proposals won't protect Americans from our gravest cross-border threat: the possibility that a ship, truck or train will one day import a 40-foot cargo container in which terrorists have hidden a dirty bomb or nuclear weapon.

The Bush administration maintains that it has a smart strategy to reduce this risk. A new 24-Hour Rule requires that importers report the contents of their containers to customs inspectors one day before the boxes are loaded on ships bound for the United States. The Department of Homeland Security's National Targeting Center then reviews the data, checking against other intelligence to determine which boxes may pose a threat. Although the containers deemed high risk are inspected at cooperating foreign ports or when they enter the United States, the rest--more than 90 percent--land here without any perusal.

We have two concerns about this strategy. First, it presumes that the United States government has good enough intelligence about Al Qaeda to reliably discern which containers are suspicious and which are not. But our inability to thwart the attacks in Iraq demonstrates that we lack such specific tactical intelligence. And supporting customs inspectors, who must make the first assessment of risk, is not a priority for the intelligence agencies. Inspectors must rely on their experience in spotting anomalies--a company that claims to be exporting pineapples from Iceland, for example.

Second, determined terrorists can easily take advantage of the knowledge that customs inspectors routinely designate certain shipments as low risk. A container frequently makes 10 or more stops between its factory of origin and the vessel carrying it to American shores. Many of the way stations are in poorly policed parts of the world. Because name-brand companies like Wal-Mart and General Motors are widely known to be considered low-risk, terrorists need only to stake out their shipment routes and exploit the weakest points to introduce a weapon of mass destruction. A terrorist cell posing as a legal shipping company for more than two years, or a terrorist truck driver hauling goods from a well-known shipper, can also be confident of being perceived as low risk.

So what needs to be done? A pilot project under way in Hong Kong, the world's largest container port along with Singapore, offers one piece of a potential solution. At an estimated cost of $7 per container, new technology can photograph the box's exterior, screen for radioactive material, and collect a gamma-ray image of a box's contents while the truck on which it is carried moves at 10 miles per hour.

Terrorists can defeat radiation sensors by shielding a dirty bomb with dense materials like lead. But by combining those sensors with gamma ray images, the Hong Kong system allows inspectors to sound the alarm on suspiciously dense objects. Inspectors would need to analyze enough of the scans--perhaps 20 percent to 30 percent--to convince terrorists that there is a good chance that an indistinct image will lead a container's contents to be sent for more reliable X-ray or manual examinations. Images of container contents would then be reviewed remotely by inspectors inside the United States who are trained to spot possible nuclear weapons.

If terrorists were to succeed in shipping a dirty bomb, for example, the database of these images could serve as a kind of black box--an invaluable forensic tool in the effort to identify how and where security was breached. That information could help prevent politicians from reacting spasmodically and freezing the entire container system after an attack.

Such a program could significantly reduce the likelihood that terrorists will smuggle plutonium or a dirty bomb through American ports. But it still would not stop a terrorist from importing highly enriched uranium, which can be used to construct a nuclear weapon. Lengthening the time that a container is screened for radiation would help, and this could be done without increasing waiting times if additional monitors were added to the Hong Kong system near the gate where the trucks must already stop for driver identification checks. Better still would be for the Department of Homeland Security to make the development of new technology that can recognize the unique signature of highly enriched uranium an urgent priority.

Finally, we must find ways to ensure that terrorists do not breach containers before shipments arrive at loading ports. Sensors should be installed inside containers in order to track their movements, detect any infiltration and discern the presence of radioactive material. Where boxes are loaded, certified independent inspectors should verify that companies have followed adequate protocols to ensure that legitimate and authorized goods are being shipped.

Taken together, these recommendations will require new investments and an extraordinary degree of international cooperation. But increased container security will not only help the United States prevent terrorism, it will also help all countries reduce theft, stop the smuggling of drugs and humans, crack down on tariff evasion and improve export controls. What's more, such a program would require an investment of just one one-hundredth of the capital that could be lost if we shut down the global container shipping system after an attack.

Container security is a complex problem with enormous stakes. American officials insist that existing programs have matters well in hand. But we cannot afford to take these perky reassurances at face value while the same officials fail to embrace promising initiatives like the Hong Kong pilot project.