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.

At a time of unusual US interest in south Asia it is useful to see how specialists there look at the two issues explored in this book -- the Kashmir conflict and south Asian nuclearisation. Twelve of the 15 contributors are US-based and therefore it is not surprising that the book is largely by Americans for Americans. But this does not detract from its value for Indians and Pakistanis, because the scholarship is impressive and analyses mostly free of bias. The volume contains 13 essays including a short introductory one by the editors. The remaining 12 are grouped into three parts.

The four essays in the first group (Pakistan: Politics and Kashmir) are "Islamic Extremism and Regional Conflict in South Asia" by Vali Nasr, "Constitutional and Political Change in Pakistan: The Military-Governance Paradigm" by Charles H. Kennedy, "The Practice of Islam in Pakistan and the Influence of Islam in Pakistani Politics" by C. Christine Fair and Karthik Vaidyanathan, and "Pakistan's Relations with Azad Kashmir and the Impact on Indo-Pakistani Relations" by Rifaat Hussain.

Vali Nasr provides a succinct account of how Islamic fervour and Islamic extremism grew in Pakistan after 1971 and how political players in the country, especially the army, tried to make use of it for domestic political and foreign policy gains. He provides a good analysis of how the Pakistani elite is torn between de-emphasising Islam for the sake of socioeconomic gains and stressing it for political advantage. In case of the army there is the additional factor of "jihadi" usefulness in pursuing regional strategic aims.

Charles Kennedy presents an interesting analysis of how the army captures power and holds on to it. He shows how Ayub Khan, Zia-ul-Haq and Musharraf have adopted essentially the same approach in this regard -- following the stages of making things legal, eliminating political opponents, becoming president, stressing local government, intimidating bureaucracy and judiciary, fixing the constitution and orchestrating elections. Two key observations he makes at the end are "the failure to develop a stable constitutional system is the fault of both Pakistan's military and civilian leadership" and that "constitutional stability can only be achieved if there is an accommodation between the interests of the two sets of actors."

Christine Fair and Karthik Vaidyanathan have tried to assess the influence of Islam in Pakistan partly on the basis of three polls conducted to gauge Muslim reaction to war against terrorism, and partly on the basis of interviews. Two noteworthy conclusions of the authors are that there is little popular support for extremist Islam in Pakistan (the good performance of MMA in the 2002 elections is rightly attributed to the political vacuum created by Musharraf and strong post-9/11 anti-Americanism), and that the Pakistan military's current effort to control, rather than eradicate, terrorism cannot work.

Rifaat Hussain has given a detailed account of India-Pakistan relations during 1979-2004, but his effort to explain Pakistan's relations with "Azad" J and K does not go beyond the little that is generally known. The lack of detailed, unbiased information about the society and politics of "Azad" J and K, which Pakistan pretends is not under its thumb, and of northern areas, which Pakistan has unabashedly incorporated into itself, is a major knowledge-gap that handicaps the search for peace in J and K.

The four essays in the second group (India: Politics and Kashmir) are "Who Speaks for India? The Role of Civil Society in Defining Indian Nationalism" by Ainslie T. Embrie, "Hindu Nationalism and the BJP: Transforming Religion and Politics in India" by Robert L. Hardgrave Jr., "Hindu Fundamentalism, Muslim Jihad and Secularism: Muslims in the Political Life of the Republic of India" by Barbara D Metcalf, and "Jammu and Kashmir in the Indian Union: Politics of Autonomy" by Chandrashekhar Dasgupta.

In his essay Ainslie Embrie has tried to explicate the complex relationship between the state and civil society in India. The tension and overlap between secular and Hindu nationalisms have been presented with deep understanding. The Gujarat massacres of 2002 have been explained in relation to the various constituents of the Sangh parivar. Indian attitudes to matters of sub-nationalism have been explained not only in relation to Kashmir but also to the north-east and Punjab.

Robert Hardgrave's essay covers much the same ground although the focus is more squarely on the BJP and the RSS. He speaks of sections within the RSS that want to align "Hindu" India with the west against Islam. At the same time he underscores how the demands of power have moderated the ideological temper of the BJP. Both Embrie and Hardgrave have written with western readers in mind and much of the ground they have covered would be familiar to Indians.

Barbara Metcalf's essay about Muslim Indians draws attention to the fact that the post-9/11 war against terrorism evoked no response from them, unlike the case with Muslims elsewhere. She has explained thoughtfully the reasons for this as well as for the rise in anti-Muslim sentiments in India from the 1980s. The contents of this essay can provide useful insights to Indians and Pakistanis. Metcalf warns that Hindu extremism can help recruit Muslim terrorists in Pakistan and Bangladesh and, in the long run, possibly within India itself. She also makes a case for declaring organisations like the VHP "terrorist" in the light of Gujarat killings.

Chandrashekhar Dasgupta's essay on J and K and autonomy is "balanced" by Indian standards. He writes that New Delhi should "accommodate Kashmiri demands for autonomy to the maximum extent compatible with the legitimate regional interests of Jammu and Ladakh and with the requirements of democracy and good governance in the state as a whole. The interests of Jammu and Ladakh can be protected by a mix of regional autonomy; devolution of power to lower (district, sub-divisional and panchayat) levels; and an equitable inter-regional revenue-sharing formula." But while offering this sound advice, Dasgupta has carefully steered clear of examining its practical implications.

The four essays in the final group (India's and Pakistan's Nuclear Doctrines and US Concerns) are "The Stability-Instability Paradox: Misperception, and Escalation Control in South Asia" by Michael Krepon, "Pakistan's Nuclear Doctrine" by Peter R. Lavoy, "Coercive Diplomacy in a Nuclear Environment: The December 13 Crisis" by Rajesh M. Basrur, and "US Interests in South Asia" by Howard B. Schaffer. In the reviewer's view, this is the most interesting of the three sections in the book and merits careful reading in both India and Pakistan.

Michael Krepon has explored the ramifications of the use of force by south Asia's nuclear-armed adversaries. He stresses the danger emanating from the two sides drawing (largely for public consumption, in the reviewer's view) opposing lessons from tests-of-will like the Kargil war and Operation Parakram. A useful point to note is how Krepon has, over the years, shifted stress from nuclear confidence building measures(CBMs) to conflict resolution in reducing nuclear risks in south Asia. This can be seen from the following sentences in his concluding paragraph: "Much could go badly wrong on the subcontinent unless Pakistan's security establishment reassesses its Kashmir policy and unless New Delhi engages substantively on Islamabad's concerns and with dissident Kashmiris" and "The best chance of defusing nuclear danger and controlling escalation lies in sustained and substantive political engagement." Nuclear CBMs can only do so much.

Nuclear Doctrine

Peter Lavoy's essay is a good piece on Pakistan's nuclear doctrine. He has listed eight separate "uses" for Pakistan's nuclear weapons. In specific relation to India, there are four, viz (i) Last resort weapons to prevent military defeat or loss of territory; (ii) Deterrent to conventional military attack; (iii) Facilitators of low-intensity conflict; and (iv) Tools to internationalise the Kashmir issue. He has drawn attention to the fact that Pakistan's nuclear "redlines" are vague which, the reviewer might add, is true of all countries that reserve the right of "first use."

Rajesh Basrur's essay is about the coercive and nuclear dimensions of Operation Parakram. His narrative of events, diplomatic moves and public statements is valuable for separating chaff from wheat. He has drawn attention to how much India's "compellence strategy" was played out through the US, which had forces in close vicinity. During the confrontation both India and Pakistan sought to "create a fear of nuclear war in the global community, especially the US". He also highlights the fact that India decided to withdraw its forces when Pakistan ceased "responding" to Indian pressure.

The book has no conclusion. The last essay is by Howard Schaffer on US interests in south Asia. Schaffer writes about how the relatively low US interest in the India-Pakistan hostile relationship began to climb in the 1980s when the threat of nuclear war entered the calculus. He says "The US has now come to regard Kashmir less in terms of the equities of the issue -- the lot of the Kashmiri people, the morality or immorality of the insurgency in the Kashmir Valley. Instead it sees the dispute primarily as a tinderbox that could be the flashpoint of a nuclear conflagration." He concludes his essay with the comment that "Washington's view of US interests in the region and the way it goes about promoting them" is unlikely to become more consistent than in the past. Both are valid observations and Indians and Pakistanis would do well to mull over their many implications.

It is not stated in the book, but this volume had its beginnings in a conference at the Asia-Pacific Research Centre in Stanford in early 2003. This was soon after Operation Parakram and before India-Pakistan relations began to thaw in late 2003. Although contributors have updated their narratives to mid-2004, the milieu in which the arguments have evolved was a period of considerable tension. The peace possibilities that have opened up in early 2004 and have got slowly augmented since have, therefore, not been adequately factored in. The book has avoided making any kind of prediction about peace prospects in south Asia although the very title of the book leads the reader to expect some exploration in this area.

Ellen Johnson Sirleaf's inauguration as the president of Liberia marks a watershed in the country's tumultuous history.

Twenty-five years of misrule and civil war under Samuel Doe, Charles Taylor, and successive interim governments have left the country in ruins. Nearly 300,000 Liberians lost their lives, average income is one-eighth what it was in 1980, and large majorities of the population subsist in dire poverty.

Since United Nations and US troops ousted Taylor in 2003, a fragile peace has taken hold, supported by 15,000 UN peacekeepers. With free and peaceful elections under their belts, Liberians are feeling new optimism and hope. Markets here are bustling, stores are freshly painted and open for business, and newspapers and radios feature lively debate.

The new government is a clear break from a past characterized by rule by force, extensive corruption, and a culture of impunity. Sirleaf, the first African woman elected head of state, has been an outspoken champion of accountability, transparency, and good governance for decades, a stance that landed her in jail twice and was a hallmark of her opposition to past governments and campaign for the presidency.

Already change is underway. She has instituted a code of conduct and full financial disclosure for senior officials, and endorsed a program that will install internationally recruited financial controllers in several state enterprises and create a strong anticorruption commission. Her government plans to publish financial accounts on the Web, make it easier for whistleblowers to report infractions, and rewrite Liberia's outdated constitution to firmly establish participatory democracy, decentralize power, and install robust checks on the executive.

Recovery from deep conflict in Africa is not easy, but we know it is possible. Mozambique was destroyed by civil war in the 1980s, but its democratically elected government led the way to peace, stability, and a doubling of income in a dozen years. Sierra Leone suffered a blood bath in the 1990s, but the 1999 peace agreement and 2001 elections brought stability and economic growth of 7 percent a year. Rwanda's genocide was followed by a recovery that few could have imagined.

But Sirleaf faces a daunting task. Liberia's recovery will depend mainly on Liberians themselves, but it will require strong international support, just as in Mozambique, Sierra Leone, and Rwanda.

West Africa's civil wars have spawned widespread smuggling of diamonds, transshipment of drugs, and easy money laundering opportunities for global terrorist groups. Liberia's historic moment provides the U.S. administration a chance to show it is serious about supporting nascent democracies, creating stability in a volatile region, and providing economic opportunities for Africa's poorest countries.

First, the United States must continue its crucial role in the demobilization of combatants and commit to long-term rebuilding of Liberia's police and army. The new government must be able to maintain and enhance security to begin to recover.

Second, the administration should support rapid and comprehensive forgiveness of Liberia's debts, which were mainly undertaken and wasted by the rapacious Doe government. It makes no more sense to stick today's Liberians with the bill, including 20 years of accumulated interest, than to force today's Iraqis to pay Saddam Hussein's bills.

Third, and perhaps most urgent, Congress should approve supplemental funding of $50 million to $100 million to support the new government. Unfortunately, Congress recently cut the administration's initial request for Liberia, a short-sighted step that sent the wrong signal to a struggling democracy and old ally at a crucial turning point. These funds would build critical infrastructure, put kids back into schools, and continue vital training for security forces. It would give Liberians their best chance of securing peace and basic freedoms.

You're being watched...Congress will soon hold hearings on the National Security Agency's domestic spying program, secretly authorized by President Bush in 2002. But that program is just the tip of the iceberg.

Since 9/11, the expansion of efforts to gather and analyze information on U.S. citizens is nothing short of staggering. The government collects vast troves of data, including consumer credit histories and medical and travel records. Databases track Americans' networks of friends, family and associates, not just to identify who is a terrorist but to try to predict who might become one.

Remember Total Information Awareness, retired Adm. John Poindexter's effort to harness all government and commercial databases to preempt national security threats? The idea was that disparate, seemingly mundane behaviors can reveal criminal intent when viewed together. More disturbing, it assumed that deviance from social norms can be an early indicator of terrorism. Congress killed that program in 2003, but according to the Associated Press, many related projects continued.

The Defense Advanced Research Projects Agency runs a data-mining program called "Evidence Extraction and Link Discovery", which connects pieces of information from vast amounts of data sources. The Defense Intelligence Agency trawls intelligence records and the Internet to identify Americans connected to foreign terrorists. The CIA reportedly runs Quantum Leap, which gathers personal information on individuals from private and public sources. In 2002, Congress authorized $500 million for the Homeland Security Department to develop "data mining and other advanced analytical tools." In 2004, the General Accounting Office surveyed 128 federal departments and agencies to determine the extent of data mining. It found 199 operations, 14 of which related to counterterrorism.

What type of information could these mine? Your tax, education, vehicle, criminal and welfare records for starters. But also other digital data, such as your travel, medical and insurance records - and DNA tests. Section 505 of the Patriot Act (innocuously titled "Miscellaneous National Security Authorities") extends the type of information the government can obtain without a warrant to include credit card records, bank account numbers and information on Internet use.

Your checking account may tell which charities or political causes you support. Your credit card statements show where you shop, and your supermarket frequent-buyer-card records may indicate whether you keep kosher or follow an Islamic halal diet. Internet searches record your interests, down to what, exactly, you read. Faith forums or chat rooms offer a window into your thoughts and beliefs. E-mail and telephone conversations contain intimate details of your life.

A University of Illinois study found that in the 12 months following 9/11, federal agents made at least 545 visits to libraries to obtain information about patrons. This isn't just data surveillance. It's psychological surveillance.

Many Americans might approve of data mining to find terrorists. But not all of the inquiries necessarily relate to terrorism. The Patriot Act allows law enforcement officers to get "sneak and peek" warrants to search a home for any suspected crime - and to wait months or even years to tell the owner they were there. Last July, the Justice Department told the House Judiciary Committee that only 12% of the 153 "sneak and peek" warrants it received were related to terrorism investigations.

The FBI has used Patriot Act powers to break into a judge's chambers and to procure records from medical clinics. Documents obtained by the American Civil Liberties Union recently revealed that the FBI used other new powers to eavesdrop on environmental, political and religious organizations.

When Congress looks into domestic spying in the "war on terror," it should ask a series of questions:

• First, what information, exactly, is being collected? Are other programs besides the president's NSA initiative ignoring traditional warrant requirements? Are federal agencies dodging weak privacy laws by outsourcing the job to private contractors?
• Second, who has access to the data once it is collected, and what legal restrictions are set on how it can be used or shared?
• Third, who authorized data mining, and is its use restricted to identifying terrorists?
• Fourth, what is the collective effect of these programs on citizens' rights? Privacy certainly suffers, but as individuals begin to feel inhibited in what they say and do, free speech and freedom of assembly also erode.
• Fifth, how do these data collection and mining operations deal with error? As anyone who's tried to dispute an erroneous credit report can attest, once computer networks exchange data, it may be difficult to verify its accuracy or where it entered the system. Citizens who do not know they are under surveillance cannot challenge inaccurate information that may become part of their secret digital dossier.

What will Congress do to ensure that the innocent remain so?

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.

One of the less publicized but perhaps most important matters before President Bush on his recent trip to South Korea for the annual Asia-Pacific Economic Cooperation summit was that of relations between the United States and the host country. Although South Korea has long been a close ally of the United States, relations between the two have cooled in recent years, and the alliance has come under great strain. Bush's trip did not set a new direction for the alliance, which has been drifting for the past few years.

There is a way to reverse this cooling in relations, I believe -- to promote U.S. strategic interests in the region, including denuclearization of North Korea; to retain U.S. influence there; and to strengthen a long-standing alliance. What is needed is an effort to widen the "North Korea problem" from one of nuclear weapons to one of unification.

Controversy over the fraying U.S.-South Korea alliance focuses almost exclusively on cultural or emotional issues. In the United States there are some who feel that South Koreans are insufficiently grateful for the steadfast U.S. support to South Korea, particularly for the American lives lost in defense of the South during the Korean War of 1950-53 and for the extensive economic and military aid since. Others feel that rising anti-American sentiment in South Korea reveals the naivete of a younger generation of Koreans who are insufficiently worried about the North Korean threat.

But the problems in the alliance are not a result of emotion, naivete or ingratitude. Indeed, even if none of those emotional and cultural issues existed, the alliance would still be in dire need of revision. To find the best path forward for both the United States and South Korea, we need to focus on the real issues.

The main factor straining the alliance is the unresolved Korean War and the continued division of the peninsula. This has created differing long-term strategic concerns for the United States and South Korea.

For South Korea, the key issue is not North Korean nuclear weapons -- it never was. South Korea's overriding concern is how to resolve the issue of national unification and integrate North Korea back into the world's most dynamic region, whether or not there are nuclear weapons. All other South Korean foreign policy issues take second place.

In contrast to Korea's regional issues, U.S. concerns are global and military. For at least the next several years, the United States will be mainly concerned with countering potential terrorist threats. Distracted by the overwhelming focus on anti-terrorism, homeland security and other issues, the United States has viewed its Korea policy as a narrow extension of its anti-terrorism policy, focusing almost exclusively on denuclearizing the North. These different strategic priorities have led to severe strains between the two allies, despite the desire of both to maintain a close relationship.

The United States can improve its position in East Asia, as well as solidify its alliance with South Korea, by widening its focus beyond North Korean denuclearization and coming out strongly and enthusiastically in favor of Korean unification. Although the United States rhetorically supports unification, it has been noticeably passive in pursuing policy to that end.

Such a policy shift would achieve many U.S. goals and would strengthen our alliance with South Korea in the process.

First and foremost, denuclearization is far more likely to occur with a change in North Korea's regime and a resolution to the Korean War than it is without resolving that larger issue. Until now the United States has put denuclearization first, without making much progress. Folding the nuclear issue into the larger issue would provide far more leverage on both questions and potentially create new or broader areas for progress.

Second, such a policy would provide grounds for agreement between U.S. and South Korean policymakers from which they could cooperate and work together, rather than against each other. Exploring the best path toward unification will require both economic and military changes in the North -- changes that will provide the United States with more flexibility to rebalance its own forces in the region.

Finally, it would put the United States in a solid position to retain goodwill and influence in Korea after unification -- something that is far from ensured today, when many South Koreans are skeptical about U.S. attitudes and policies toward the region. If the United States is seen as a major source of help for unification, it is far more likely that the post-unification orientation of Korea will be favorable to Washington.

This would be a major policy change for the United States, but given the importance of the region and of the Korean Peninsula, it is the best path to follow.