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.

This article adopts a two-tiered approach: it provides a detailed, historical account of anti-terrorist finance initiatives in the United Kingdom and United States--two states driving global norms in this area. It then proceeds to a critique of these laws. The analysis assumes--and accepts--the goals of the two states in adopting these provisions. It questions how well the measures achieve their aim. Specifically, it highlights how the transfer of money laundering tools undermines the effectiveness of the states' counterterrorist efforts--flooding the systems with suspicious activity reports, driving money out of the regulated sector, and using inappropriate metrics to gauge success. This article recognizes that both states consider the fight against terrorism to be partly military but also a matter of bringing certain democratic principles to bear. Critics have been quick to condemn some of the measures for their encroachments into civil liberties. My goal is not to measure the success of the laws according to any particular ideology but rather, accepting the governments' democracy-promoting goals, and the role these play in generating domestic and international support, to clarify which components do not appear to serve the states' aims.

This article won Stanford Law School's Carl Mason Franklin Prize for 2005-2006, for most distinguished written work in international law.

The Bush administration's response to the September 11 attacks has rendered more urgent Al Qaeda's stated objective to eject the United States from the Middle East. The aim here is not to evaluate the direction of the war on terrorism, but to explore why Al Qaeda has been so unsuccessful in capitalizing on its political violence. The article begins with the premise that terrorism is a communication strategy. It contends that Al Qaeda's policy failures are due to its inability to convince Bush that it would refrain from attacking Americans if the United States moderated its Middle East policies. Borrowing from the literature in political psychology and perception and misperception in international relations, the article offers several explanations for Al Qaeda's ineffectiveness in getting this message across. The article concludes by deriving general observations about the limitations of terrorism as a form of political communication.

Chapter 6 in Reappraising Openheimer: Centennial Studies and Reflections, edited by Cathryn Carson and David A. Hollinger (Office for History and Science of Technology, University of California, Berkeley, 2005).

The editors write: "From the beginning all the way up to the present, the Soviet nuclear weapons project has served as foil for the American effort. It preoccupied Robert Oppenheimer's minders in the Manhattan Project, fixated by the possibility of espionage; it drove his postwar attempts to achieve international control of atomic weapons just as surely as it lit up his opponents' mistrust of his stance on the hydrogen bomb. Throughout the arms race, Soviet progress vis-a-vis American weapons production helped drive the dynamic of the Cold War. More recently, Soviet and post-Soviet sources have inspired careful reanalysis of the dual courses of the two nations' nuclear projects. That effort has shed new light on the conditions under which Oppenheimer's wartime labors could find the conclusion they did. . . .

"David Holloway explores parallels between Robert Oppenheimer and his Soviet counterpart, Iulii Khariton. Similarities in background and differences in role make Holloway's contrast instructive."

On June 16, 2002, Dennis Pluchinsky, a senior intelligence analyst at the U.S. Department of State, wrote an article in the Washington Post calling for censorship. The article began, "I accuse the media in the United States of treason." Pluchinsky, who worked counterterrorism in the government for twenty-five years, pointed to post-9/11 articles that revealed not scientific advancements, but American vulnerabilities in regard to the food supply, electricity, chemical production, transportation, and border security. He suggested that research conducted by the media could not have been funded by one, single terrorist organization: "Our news media, and certain think tankers and academicians, have done and continue to do the target vulnerability research for them."

Pluchinsky has a point. Terrorist organizations can and do use the media--and the protections afforded speech in the United States and the United Kingdom--to obtain and disseminate critical information.

The crucial point is this: Both liberal, democratic states, and nonstate terrorist organizations need free speech. Under what circumstances are the interests of the state secured and the opportunism of terrorist organizations avoided? Here, the experiences of the United States and United Kingdom prove instructive. On both sides of the Atlantic, where the state acts as sovereign, efforts to restrict persuasive political speech have relaxed over time to allow for more criticism. In the United States, Brandenburg v. Ohio cemented this shift. In the United Kingdom, change came gradually. The practical elimination of treason and seditious libel, and incorporation of the European Convention of Human Rights (ECHR) into domestic law through the 1998 Human Rights Act (HRA), marked the transition. If free speech remains central to our understanding of liberal democracy, it would nevertheless be naïve to rely on these alterations to protect expression in the contemporary counterterrorist environment--regardless of how remarkable they might be in the context of what went before.

Underlying my argument in this paper is a deeper concern that centers on the shifting nature of technology. What the average person could have done in 1776, or for that matter, 1976, to hurt either state pales in comparison to what a person with basic knowledge of microbiology, $1000, and a lab can do today. But neither American nor British law appears to have come to terms with what weapons of mass destruction, in terrorist hands, means for free speech.

This article won the 2004-2005 Steven M. Block Civil Liberties award for the best piece of writing in civil liberties at Stanford Law School. It also won second place in the national competition for the 2005 Judge John R. Brown Award for Excellence in Legal Writing, which recognizes the best legal writing by U.S. law students.