Given Tehran's defiant response to the European and American effort to constrain its nuclear program, it is time for bolder diplomacy out of Washington. U.S. President George W. Bush should take a page from the playbook of Ronald Reagan, who negotiated with an evil Soviet regime--competing in the war of ideas, but addressing the enemy's security concerns through arms-control agreements.

Iran's intransigence is both deeply unfortunate and perfectly predictable. It is unfortunate because Tehran's refusal to suspend its uranium-enrichment operations immediately--as demanded in July by the U.N. Security Council in a legally binding resolution--suggests that Iran is moving more quickly than expected toward a nuclear-weapons capability. Tehran has now turned the nuclear crisis into a test of the whole U.N. Security Council system. And Russia and China's current position, threatening to veto any biting sanctions against Iran, suggests that the Security Council may well fail this crucial test.

Tehran's response is predictable, however, because the offer on the table contains both inadequate economic carrots and barely credible threats of sanctions and military force. The carrots appeared impressive at first glance--in return for a suspension of enrichment we reportedly promised to provide light-water nuclear reactors and to help Iran with civil aviation and telecommunications technology. But we did not offer the one incentive that might possibly work, security guarantees that could reduce Iran's desire for nuclear weapons.

This omission is striking. The Iranian government can't talk openly about their security concerns because that would blow their cover story that the nuclear program is only for energy production. And Washington does not want to discuss such worries because it wants to keep open the possibility of removing the regime by force. "Security assurances are not on the table," U.S. Secretary of State Condoleezza Rice too cleverly argued this spring: "It is a little strange to talk about security guarantees ... I thought the Iranian position was that they weren't developing a nuclear bomb."

This is partly a crisis of our own making, as the Bush administration has practiced the reverse of Teddy Roosevelt's maxim--speaking loudly and carrying a small stick. Think about how Tehran reacted when Bush stated (in his second Inaugural Address), "The rulers of outlaw regimes can know that we still believe as Abraham Lincoln did: 'Those who deny freedoms to others deserve it not for themselves; and, under the rule of a just God, cannot long retain it." Or when Bush dramatically told reporters last April that "all options are on the table," in direct response to a question about whether he was considering a nuclear attack against Iran. Such statements only encourage Iran to develop a nuclear deterrent quickly, before the United States can carry out its perceived aggressive intent. Last month, Iran's National Security Council Secretary Ali Larijani pointedly complained about such rhetoric. "How can a side that wants to topple the regime also attempt to negotiate?"

Given the current vulnerability of U.S. forces in Iraq, the deteriorating situation in Afghanistan, and the lack of Israeli success against Hizbullah, Iranian officials seem confident that they face no immediate threat of a U.S. military assault. But they are clearly worried that Bush just might attack Iran right before he leaves office in January 2009, or that his successor might do so once U.S. forces withdraw from Iraq.

The best way to prevent a nuclear Iran is for Washington to offer the kind of security assurances that might reduce support in Tehran for building a nuclear arsenal. It will be hard to make such assurances credible, but a public U.S. promise to take forcible regime change off the table, and a U.N. Security Council commitment to protect the "political sovereignty" of Iran could help. Involving the Security Council could also pull China and Russia back into the nonproliferation coalition and enhance the U.N.'s legitimacy.

There is very little time left, which means negotiations should begin despite Iran's unfortunate opening position. Tehran's response reportedly indicated a willingness to negotiate all aspects of its nuclear program, so working out an agreement for Iran to limit itself to low-level uranium enrichment might still be possible. This would work only if Tehran accepts full IAEA inspections and a freeze on future centrifuge construction. Will they? The one thing that might cause Tehran to do so, and that would compensate for any loss of face, would be an assurance that the United States will not launch another preventive war, as it did in Iraq, to remove the Iranian regime. If in turn we get a nuclear-free Iran, that's a good deal for the West as well.

Imagine a land where bombs explode almost daily and children are killed by terrorists without conscience. On one side we find a people who suffered through the horror of slave-labor death camps; on the other side a people who suffered through a terrible war -- which they began when what they felt was their property was seized from them -- a terrible defeat and (for them) a terrible occupation. Now imagine those same peoples 15 years later, living side by side, peacefully.

This sounds like a pipe dream: The Middle East could never be this way, we think. But we do not need to imagine this land.

We are living in it.

One century after America's Civil War, the descendants of slaves daily faced the twin terrors of homicide and arson. Yet only 15 years after the rise of the Rev. Martin Luther King Jr., the back of segregation and neo-Confederate violence had been broken.

Can Palestinians likewise mount a successful, nonviolent movement toward peaceful co-existence with their former adversaries? In short, can history repeat itself?

How expensive would it be for us if it did not? America spends an estimated $3 billion a year in support of Israel. This support is justified because Israel is a democracy and our main ally in the region. Yet we also spend $2 billion supporting Israel's nondemocratic neighbor, Egypt. Billions more have been spent maintaining bases in Saudi Arabia, Kuwait and now Iraq. We justify these expenditures by surrendering to the serpentine excuses of realpolitik: We need the support of key figures and families in the region, we say, and so we have to work with them. Just as we once said of the Dixiecrats and other segregationist politicians in the American South.

We can transform this paradigm, as we did then, and at little cost to ourselves. We can utilize the experience of the civil rights movement -- which Secretary of State Condoleezza Rice knows all too well (her childhood friend was killed by an improvised explosive device in segregated Birmingham) -- to assist Palestinians in their stride toward peace. What we need is a Muslim Martin Luther King.

Many believe that leaders are born, not made, but programs to cultivate leadership and promote good will among men have been used successfully for generations. Oxford's Rhodes Scholarship is one such example. Its idea is to bring the best and brightest from the British Commonwealth (and beyond) to build strong ties among English-speaking peoples, and stronger ties to England. Founder Cecil Rhodes, pirate though he was, wished for there to be "an understanding between the three great powers" -- America, Britain and Germany -- that "will render war impossible."

What we recommend is a sister program for the Middle East. One could hold a competition for the 30 best young orators in the Palestinian diaspora. (King first gained prominence at age 26, and the Rhodes Scholarship is only for men and women under that age.) Send them to an American institution such as Stanford University, where they could study for the doctorate under Professor Clayborne Carson, director of the Martin Luther King Jr. Papers Project and historian of the civil rights movement and the Student Non-Violent Coordinating Committee. Then, after they have spent several years studying the African American experience with special courses and lecturers, focusing especially on the efficacy of nonviolent direct action, send them back to their native lands.

This is no program of indoctrination. Indeed, it would be detrimental if American spy organizations were to infiltrate or interfere with the King scholars in any way: the scholars would lose all credibility at home. Just as King spoke out against Southern injustice (and American injustice in Vietnam), the King scholars must be free to criticize America and, it is to be expected, the occupation. They would not be able to lead the Arab street otherwise.

By bringing young leaders from the region, we would avoid disasters like the U.S. Army's flirtation with mathematician Ahmed Chalabi, a man who had no real roots in Iraq, but whom America still wished to enthrone as a new shah. The Chalabi experiment blew up in America's face like a roadside bomb.

The King scholarship program might cost only $2 million per year -- an endowment of perhaps $20 million could put it on its feet indefinitely. And, coupled with the application of "soft power," the export of American culture -- notably, hip-hop music, which serves both as a mechanism for promoting intercultural understanding and as a nonviolent channel for youthful aggression -- one could reasonably expect to see the flower of peace bloom in the desert of despair.

Two specific aspects of the civil rights movement would be most effective in resolving the Israeli-Palestinian conflict: first, the proper utilization of legal instruments as a way to wage a nonviolent campaign; second, the utilization of mosques to mobilize a nonviolent grassroots struggle. Mosques in the West Bank and Gaza can be used to promote peace over violence and terrorism, and the African American experience can teach Palestinians how to do this.

In "The Trial" by Franz Kafka, at one point two men stand outside a gate. One seeks to enter; the other seeks to prevent him from entering. Both men wait there for their entire lives. Though one is guard and the other the one guarded, both men are prisoners.

In game theory, the branch of mathematics made famous by "A Beautiful Mind," there is a paradox called the Prisoners' Dilemma. Each of two prisoners may believe it is in his best interests to harm the other, but one can mathematically prove that both men would be better off if they cooperated. A King scholars program might help us resolve the prisoners' dilemma that is the Middle East.

This is a utopian dream, perhaps. But another man dreamed, once, and we all know what became of that man's dream.

We are living it.

Before attacking Iraq in March 2003, the United States told the world that Saddam Hussein had reconstituted his nuclear weapons program in defiance of the United Nations. That claim, used to justify the war, was based on assessments provided by the United States intelligence community. But as everyone now knows, those assessments were wrong. So Jeffrey T. Richelson's history of American nuclear intelligence, including our attempts to learn about Iraq's nuclear program, could hardly be more timely.

In "Spying on the Bomb," Richelson, the author of several books on American intelligence, has brought together a huge amount of information about Washington's efforts to track the nuclear weapons projects of other countries. He examines the nuclear projects of Nazi Germany, the Soviet Union, China, France, Israel, India, South Africa, Taiwan, Libya, Pakistan, Iran and North Korea, as well as Iraq. Through interviews and declassified documents as well as secondary works, he sets out briefly what we currently know about those projects and compares that with assessments of the time.

This may sound like heavy going, but Richelson writes with admirable clarity. And along the way he has fascinating stories to tell: about plans to assassinate the German physicist Werner Heisenberg during World War II; about discussions in the Kennedy and Johnson administrations on the possibility of attacking Chinese nuclear installations; about Indian measures to evade the gaze of American reconnaissance satellites; and about the bureaucratic infighting over the estimates on Iraq.

The United States has put an enormous effort into gathering information about the nuclear projects of other countries. After World War II it equipped aircraft with special filters to pick up radioactive debris from nuclear tests for isotopic analysis. It created a network of stations around the world to register the seismic effects of nuclear explosions. Most important, in 1960 it began to launch reconnaissance satellites that could take detailed photographs of nuclear sites in the Soviet Union and China. Richelson occasionally speculates about the role of communications intercepts and of spies, but these appear from his account to have been much less important than the other methods of collecting information.

Through these means the United States has gathered a vast quantity of data, sometimes to surprising effect. Intelligence played a crucial role in the cold war, for instance, by reducing uncertainty about Soviet nuclear forces. Alongside such successes, however, there have been failures. One notable example concerned the first Soviet test, which took place in August 1949, much sooner than the C.I.A. had predicted. Another was the failure to detect Indian preparations for tests in May 1998, even though at an earlier time the United States, with the help of satellite intelligence, had managed to learn about preparations the Indians were making and to head off their tests.

But the most serious failure of all was in Iraq in 2003, because in no other case did the intelligence assessments serve as justification for the use of military force. The information needed for avoiding political surprise is one thing. That needed for preventive war is quite another, if only because of the consequences of making a mistake.

Beyond making the uncontroversial recommendation that "aggressive and inventive intelligence collection and analysis" should continue, Richelson draws no general conclusions. That is a pity, because his rich material points to issues that cry out for further analysis. He suggests in one or two cases that failures sprang from the mind-set of the intelligence community, but he does not elaborate on this point. He has little to say about relations between policy makers and the intelligence community, even though the quality of intelligence and the use made of it depend heavily on that relationship.

His focus is no less narrow in his discussion of foreign nuclear projects. He concentrates on the programs themselves, paying very little attention to their political context. Does that reflect a technological bias in nuclear intelligence? Would, for example, the prewar assessment of Iraqi nuclear capabilities have been more accurate if it had paid more attention to the broader political and economic circumstances of Hussein's regime?

The task of intelligence has become more complex than it was during the cold war. A single dominant nuclear opponent has now been replaced by a number of nuclear states, along with states and stateless terrorists that are aiming to get their hands on nuclear weapons. Meanwhile, the technology needed for producing nuclear weapons has become easier to acquire.

Many critics believe the recent performance of the intelligence community shows it has not responded adequately to this new situation. Richelson does not have much to say on this question; nor does he discuss the likely impact of the current reforms, initiated in response to the Iraq war, on the quality of intelligence. His reticence may imply that he does not think reform is necessary. Still, it is disappointing that he does not draw on his historical survey to discuss whether new approaches are needed for dealing with nuclear threats, and, if so, what those new approaches might be.

George Habash, a militant and former secretary-general of the Popular Front for the Liberation of Palestine, once characterized terrorism as a "thinking man's game." Using mathematics, researchers at Stanford University's Center for International Security and Cooperation (CISAC) have made fighting terrorism a thinking man's game as well.

CISAC affiliate Lawrence M. Wein of the Graduate School of Business and CISAC Science Fellow Jonathan Farley are both applying mathematical models to homeland security problems, such as preventing a nuclear detonation in a major U.S. city and determining whether terrorist cells have likely been disrupted.

Wein, who teaches operations classes about different business processes used to deliver goods and services, has focused his research on bioterrorism and border issues. He has performed, he says, the first mathematical analyses of hypothetical botulism poisoning, anthrax outbreaks and smallpox infections.

"One overriding theme of my work is that all these homeland security problems are operations problems," said Wein, the Paul E. Holden Professor of Management Science. "Just as McDonald's needs to get hamburgers out in a rapid and defect-free manner, so too does the government have to get vaccines and antibiotics out and test the borders for nuclear weapons or terrorists in a rapid and defect-free manner."

In collaboration with Stephen Flynn of the Council on Foreign Relations, a nonpartisan research center, Wein recently has conducted research to improve security at U.S. borders and ports. Port security has received significant attention recently owing to the furor over Dubai Ports World's bid to manage six terminals at major U.S. harbors. The aim of Wein and Flynn's work is to prevent terrorists from bringing into the country a nuclear weaponbe it an atomic bomb or a so-called "dirty bomb," or conventional explosive packed with radioactive waste.

"Of all the problems I've studied, this is the most important because the worst-case terrorist scenario is a nuclear weapon going off in a major U.S. city and also it is the one the government has dropped the ball on the most," Wein said. "They have done a very poor job."

Instead of using the existing approach, where U.S. Customs actively inspects a minority of containers based on information from a specialized tracking system designed to identify suspicious containers, Wein and Flynn have recommended the government use a multi-layer, passive screening system for every container entering the country. Under their system, Customs would photograph a shipping container's exterior, screen for radioactive material and collect gamma-ray images of the container's contents. If terrorists shielded a bomb with a heavy metal such as lead to hide it from radiation detectors, gamma-ray imaging would allow inspectors to see the shielding and flag the container for inspection. Wein and Flynn believe this whole process would cost about $7 per container.

"Right now about maybe 6 percent of the containers are deemed suspicious and they will go through some testing and the other 94 percent of the containers just waltz right into the country without an inspector laying an eye on them," Wein said. "What we're proposing to do is 100 percent passive testing."

Wein's earlier work addressed a different threat: bioterrorism. In 2005, Wein revealed the nation's milk supply was vulnerable--a terrorist could potentially poison 100,000 gallons of milk by sneaking a few grams of botulinum into a milk tanker. Although the government and dairy industry have collaborated to intensify the heat pasteurization formula for milk, Wein is still pushing for additional botulinum testing, which he says would cost less than 1 percent of the cost of milk.

Wein also has used math to study smallpox outbreaks, the U.S. fingerprint identification system and U.S.-Mexico border security issues. Wein's congressional testimony on the fingerprint identification system in 2004 led to a switch from a two-finger system to a 10-finger system. His 2003 research on anthrax attacks resulted in a Washington, D.C., pilot program to use the U.S. Postal Service to distribute antibiotics throughout the capital after an outbreak. Seattle is now testing a similar program.

"In Washington, D.C., now, if there is a large-scale anthrax attack, postal workers will be the first to get their Cipro and, on a voluntary basis, they will go door-to-door distributing antibiotics," Wein said.

He said the common thread throughout his research is queuing theory, or the mathematical study of waiting lines, but he also draws upon mathematical epidemiology for his smallpox studies; air dispersion models for the anthrax model; supply chain management for the milk study; probability theory for the fingerprint identification system; and models for nuclear transport and detection for his work with containers.

From tainted lactose to lattice structures

While Wein is working on improving the government's counterterrorism systems, Jonathan Farley is working to figure out when terrorist organizations have been effectively disrupted. His mathematical model is designed to help law enforcement decide how to act once they have captured or killed a terrorist or a number of terrorists in a cell.

A professor at the University of the West Indies who will chair the Department of Mathematics and Computer Science there next year, Farley is on a one-year science fellowship at CISAC. In 2003, he co-founded Phoenix Mathematical Systems Modeling Inc., a company that develops mathematical solutions to homeland security problems.

He is using lattice theory--a branch of mathematics that deals with ordered sets--to determine the probability a terrorist cell has been disrupted once some of its members have been captured or killed.

"Law enforcement has to make decisions about what resources they should allocate to target different cells," Farley said. "The model should provide them with a more rational basis for allocating their scarce resources. ... It will inform you when you're making decisions about how much time and effort and how much money you're going to spend going after a particular cell."

While at Stanford, Farley hopes to unearth the perfect structure, mathematically speaking, for a terrorist cell--or in other words, a cell structure that is most resistant to the loss of members.

"If it's possible to determine the structure of an ideal terrorist cell, you can focus on a much smaller number of possibilities, because it makes more sense to assume the adversary is going to be smart rather than stupid," Farley said.

Farley has suggested it is possible Al-Qaida and other terrorist organizations already may have figured out the perfect structure for a terror cell by trial and error.

"I don't expect Osama bin Laden to be reading lattice theory in his caves in Afghanistan," said Farley. "But if it follows from the mathematics, perhaps heuristically, the terrorists will have come to the same conclusion--that this is the best way to structure a terrorist cell."

Although Farley acknowledges his model is not a panacea for terrorism, he hopes it will help reduce guesswork that might be involved in pursuing terrorists.

"It's not that I think mathematics can solve all of these problems," Farley said. "Because it can't. But it's better to use rational means to make decisions rather than guesswork."

John B. Stafford is a science-writing intern at Stanford News Service.

President Bush's 2002 nuclear posture differs sharply from its predecessors and is relevant to the President's recently repeated assertion that he will strike first against any country that might pose a threat of using weapons of mass destruction.

The main new trend in the posture is that the US will be prepared to use nuclear weapons in a much wider range of circumstances than before. Such an emphasis has not been seen since the days of "flexible response" forty or so years ago, when tactical nuclear weapons were deployed in Europe and elsewhere.

Yet, nuclear weapons don't help much with the kinds of missions the US prepares for, including the ones noted in the posture, such as digging out deep underground facilities that might contain bio-warfare agents. Deep underground facilities are difficult or impossible to destroy without large nuclear explosions that create large amounts of fallout. Nuclear weapons are more suited for use against shallow-buried facilities (of the order of ten meters deep) but even in those cases, Hiroshima-type yields are needed, and complete destruction of the bio-agents cannot be guaranteed. Other uses mentioned to justify the posture are even more marginal in their feasibility.

Given the overwhelming US conventional advantage and the relative invulnerability of the US to all but nuclear weapons, the US nuclear posture should aim at minimizing the chances of nuclear weapons spread rather than seeking marginal gains with tactical nuclear weapons. Nuclear weapons are equalizers. Why bring them back into the forefront of regional problems, whether in the Middle East or anywhere else?

Increasing the US nuclear threat will increase the motivation of adversaries, big or small, to improve and extend their own nuclear force, or to get one if they don't already have one. The US cannot subsequently be confident that it will be the only power to use or threaten to use nuclear weapons. There are now several demonstrations of the relative ease with which states can acquire nuclear weapons. North Korea, a poor nation of 17 million people, made and separated with little help enough plutonium for perhaps one or more weapons. South Africa made at least six weapons with essentially no help. Other cases tell the same tale.

The nuclear genie is long out of the bottle and the relative stability that characterized the Cold War is also gone. Instead, the US has been pursuing an aggressive strategy of military expansion around the world and ever closer to other states' vital interests. Quite apart from the wisdom of that strategy, is it wise to couple it with an increased nuclear threat to possible adversaries, as the posture does?

In the past, the existence of a real or putative nuclear threat has been a serious motivation for states to improve and extend their own nuclear force, or to get one if they didn't already have it. That was true of the US, USSR, China, and others. The US, as the world's strongest and least vulnerable major power, should pursue a strategy that minimizes the most serious risk rather than increase it for marginal, and questionable, benefits. The posture implies a strategy that does the opposite.

A nuclear posture better suited to our times would recognize these changes. It would lay the policy basis for the following difficult, long-term, but necessary steps:

1. Minimizing the demand for nuclear weapons, focusing on Asia. Asia contains most of the world's population and might, in a few decades, have most of its wealth. Three states there (four if Israel is included) have nuclear weapons; several more could readily have them. The US nuclear posture should provide US initiatives toward a more stable security order there, one in which peaceful states will not be threatened by nuclear or potentially nuclear rivals. The Non-Proliferation Treaty provides a basis -the only existing basis- for such an order, but it needs to be updated with more inducements in the way of technical cooperation and reassurance, and more clearly defined internationally agreed sanctions if the treaty is disregarded. The US nuclear posture in essence forswears the lead in this endeavor.

2. A pattern for nuclear arms reductions that would include eventually limitations on all arsenals. Openness here is as important as numbers. The US and Russia have most of the weapons but, after the first hundred or so survivable weapons, it matters less and less how many a state has. An internationally recognized framework is needed that can be applied to the regions of the world where nuclear rivalries threaten. Instead, the US has gone the other way, with a sketchy US-Russia agreement that delays the time scale for reductions and does not provide any precedent for international agreements on inspections.

3. A strategy for addressing the problem of nuclear terrorism. The most serious dimension of that problem--the possibility of a terrorist nuclear weapon --is closely related to the proliferation of nuclear weapons and capabilities. Any strategy to avoid that has an important international dimension. Hundreds of tons of weapons-grade uranium and plutonium, most of it surplus in the US and former Soviet Union from the Cold War, need to be better secured and accounted for. A solution to the problem of keeping nuclear weapons and materials out of the tens of millions of shipping containers that crisscross the world requires international cooperation on standards, procedures, cost sharing, and inspections. A good start has been made toward these goals, mainly through the Nunn-Lugar programs, but more money and agreements are needed. A modern nuclear posture should establish the policy basis for securing those resources and agreements. There is at present no comprehensive global strategy for securing such vital agreements and establishing the institutions to enforce them. Consistent, high-priority US participation is vital to secure other countries' participation.

4. A strategy for reducing the risks of accidental nuclear launch while at the same time maintaining invulnerability of the reduced deployments. The nuclear posture briefly mentions the "rigorous safeguards" on US weapons systems and proposes to deal with the problem of accidental or unauthorized launch of "certain foreign forces" via nuclear missile defense. That is at best a partial and certainly a distant remedy. Maintaining the human and financial infrastructure for nuclear weapons system will become more difficult in the US as well as elsewhere. Given the relationship among nuclear deterrent forces, the problem cannot be solved unilaterally. A program that would use US technical leadership to improve warning and control for all states threatened by nuclear weapons is also needed. It is needed now in South Asia. Later, it could help limit crises with or among Russia and China, and help prevent proliferation in the Middle East. President Reagan, with a portion of Star Wars, and, before him, President Eisenhower, with Open Skies, had something of the kind in mind. It is time to begin thinking about how this would look in modern form.

In summary, a nuclear posture for a world with more dispersed power centers and more widely available nuclear technology should have more, not less, emphasis on international agreements. President Eisenhower stated fifty years ago that "Only chaos will result from our abandonment of collective international security." That is even truer in today's world than it was then. The present administration seems to have a bias against such agreements, which are slow to bear fruit and do not win votes. That is shown in the posture itself, which states that arms control measures will not stand in the way of nuclear weapons development.

Yet these and other agreements are essential to deal with the dangers of proliferation to unstable states, with the possible use of international trade for terrorism, and with the risk of accidents and unauthorized launch. Nuclear deterrence continues to be needed, but the last thing a modern posture should do is to bring nuclear weapons back into the forefront of regional deterrence.

Ironically, when it has committed itself to the task, the US has used international agreements more effectively than any other nation. The Cold War-- better called a Cold Peace perhaps, since the military lines of demarcation never changed while the safeguarding of Western values and collapse of the Soviet Union were brought about mainly by economic and political instruments-- saw a rise in US power and influence in good part through the use of US-led international agreements in the areas of trade and security, areas that are necessarily related. Now is not the time to give up that approach, especially not in matters relating to nuclear weapons.

Earlier this month, the so-called EU Three--Britain, France and Germany-- achieved an important victory for global security, convincing Iran to suspend its uranium enrichment and plutonium reprocessing activities pending further negotiation on its nuclear question. Though Iran claims that it does not desire a nuclear bomb, the West has long been skeptical of the oil-rich state's contention that it seeks a nuclear fuel cycle for energy purposes alone. Europe and the United States (and of course Israel) will sleep better knowing that Tehran is not pursuing enrichment activities, whatever their alleged purpose.

But the EU3 agreement, which fails to discuss consequences for Iran if it breaks the deal, is vulnerable to being undermined not only by Iran but also by the United States; both have already raised eyebrows in the wake of the accord. Iran raced to produce uranium hexafluoride, a gas that can be enriched into bomb fuel, before it began to observe the temporary suspension on Monday. And both President George W. Bush and outgoing Secretary of State Colin Powell have publicly aired their suspicions that Iran will continue its drive for nuclear weapons under cover of the deal.

At the moment, administration hawks are pressing to confront the mullahs at the United Nations Security Council, where economic sanctions could be considered; calls for using force and for regime change are likely to follow.

Military action is inadvisable at this point, because of a dearth of solid intelligence and the secretive, geographically diffuse nature of Iran's nuclear sites. If the issue reaches the Security Council with the United States and Europe continuing along divergent paths, the inevitable deadlock will deal a severe and lasting blow to international security. Therefore, the agreement must be fortified to keep the Iranians honest, the Europeans effectively engaged and the U.S. hawks bridled.

This can be achieved through a U.S.-European accord laying out trigger mechanisms for specified consequences if Iran violates certain benchmarks. For example, if Iran fails to allow inspectors the access accorded by the Nuclear Nonproliferation Treaty's additional protocol--which Iran is provisionally observing pending ratification--or resumes enrichment and centrifuge-building activities, it could face severe economic sanctions, censure by the Security Council (necessitating cooperation from Russia and China), or in the event of hostility, a forceful response.

We don't know yet whether Tehran will play by the rules. The regime has mastered the art of behaving badly and then seeking rewards for getting back into line. To date, the Europeans have played into its hands, offering carrots for compliance without wielding sticks to punish violations.

Therefore, the Bush administration's apparent comfort with a military option can serve as an important deterrent against Iranian cheating, arming the EU3 agreement with teeth that it would not otherwise have. Iran desires economic incentives but does not yet desperately need them; without a credible threat of U.S.-backed sanctions imposed by the international community, the mullahs can simply decide one day that the restrictions have ceased to be worth their while, and break any deal as though it were merely a business contract.

For the United States, accepting the EU3's carrot-based approach (provided the benchmarks are added) will show the world that it still supports negotiated diplomacy and multilateralism, even in cases where military threats loom. Participating in this framework will also send a message to Iran that the United States is not ruling out renewed relations. This would resonate with the largely pro-American Iranian populace, who despise their regime and are seeking inroads to break free of it.

But if the United States instead presents itself as a unilateralist maverick, it will hinder its own interests; the only thing Iranians disdain more than the mullahs is outside meddling with their deeply nationalistic desire for self-determination. The more overtly hostile the United States acts toward Iran, the more the mullahs are able to spin America's posture to alienate Iranians against the "Great Satan."

The way to keep the Iranian regime in check while speeding its demise is to insure the nuclear agreement through benchmarks and triggers, and then give the mullahs exactly what they ask for in terms of increased access to international institutions like the World Trade Organization.

Such carrots can also be Trojan Horses, allowing the forces of democratic reform within Iran to blossom by enabling pro-democracy elements to make global connections. The U.S. and Europe should saddle up those horses together.