Combating Terrorism: an Event Tree Approach
Richard Wilson
Harvard University
version of summer 2002


    This talk was first presented at the Global Foundation Conferences at Chatham House, London on December 5th 2001 and again at Fort Lauderdale, FL on December 12th 2001. Also at the Probabilistic Safety Analysis and Management meeting (PSAM6) in San Juan, Puerto Rico on June 24th 2002. Some suggested modifications have been included. As I prepared it I realize that it is not enough to discuss how industries may be made immune from terrorist attacks: they cannot be absolutely immune. We need what was called in the nuclear industry "defense in depth" and we need to analyze the relative importance of different steps by an "event tree analysis". I find that the actual attack is the last step in the event tree. As with more conventional uses of event trees the earlier in the chain of events that there is intervention, the easier it is, and the more effective. So I start by analyzing my immediate personal reactions to the problem. Then I discuss the problems and paradoxes of extending widely the immediate response of Americans, including myself, to the act. This includes a discussion of the way in which terrorism is defined and in which different people perceive it. This then leads to an approach which I essential; a multifaceted approach to combating terrorism of which I discuss three facets; the avoidance of world situations that breed terrorism; the containment of the terrorist; and the difficult task of limiting the damage that a terrorist might cause. This in turn maybe broken up into parts with a risk analysis approach. Finally I try, very briefly, to consider how it can all be put into perspective. It will be seen that I build primarily on my own experience and studies over a period of years.

Support for President Bush's Aim to Stop Terrorism

    After the September 11th terrorist attack on the World Trade Center and the Pentagon, I, like most Americans, had very complex feelings. Like the vast majority, I felt the animal reaction, "let us get the guy who did this". This is difficult, because in the very nature of a suicide attack the person directly responsible is dead. I agree with President Bush that the person who plans such activities is a person we want to catch and punish.  But therein lie the complications.   How do you find the planner? and what is a terrorist? When is a man a terrorist and when is he a freedom fighter? Is a terrorist a coward if he blows himself up?   Moreover, merely rooting out existing, known terrorists is a reactive approach rather than a positive approach of making society somewhat safer and/or reducing the number of terrorists.

     I also am much more aware than most Americans that the destruction of September 11th 2001 is far from unusual in the world. What is unusual, is that 2,800 people were killed in a short time, and by terrorist action.  It has been said that everything changed on September 11th .  But not so much for me. On September1st 1939, I left home on my bicycle, leaving London, Great Britain, not knowing whether I would see my parents again. 2 million children left London that day expecting imminent air raids. 15 months later the center of London looked worse than New York did after the collapse of the World Trade Center. I tend to take a long term view. Supposing that we catch the guy responsible (maybe Osama Bin-Laden) what is to stop Osama Bin Laden's associates from taking over the organization, and worse still, what is the to stop others, not yet known, becoming terrorists?  Thus I very quickly realize that one must address terrorism in many different ways of which the first and most important is to address the root causes of terrorism or as many of them as we can. This then leads me to think about the whole issue intellectually, and I find that there are many areas in which Probabilistic Risk Assessment can be very relevant.

  What should a physicist do?

    Firstly a physicist will define the problem. In this he will try to ensure that the language he uses is the same as the language his associates use so that he is properly understood. Definitions are all important. Secondly he tries to break the problem up into manageable parts. Hopefully these parts are uncorrelated with each other or at least have as few correlations as possible. In safety engineering these correlations are called "common mode failures" The analyst's skill comes in choosing the parametrization to ensure this independence as much as possible. My colleague, the late Ed. Purcell, thinking of how best to design his experimental equipment so that it could be easily adjusted, used to call this "the orthogonality of knobs". As I do this, I first notice an important scientific revolution going on in society which inevitably influences everything we try to do. The revolution of globalization.

Globalization and its Consequences

    We are developing a Global Economy. Indeed globalization seems inevitable. Globalization is more than a globalization of markets, although we know that can bring increased economic prosperity- often my avoiding the middlemen and traditional traders. The protesters at Seattle, and Genoa, and even the NGOs at Durban, understood this better than the official delegates to these conferences seemed to do. But even they failed to realize that globalization is simultaneous with, and may be a partial consequence of a major scientific revolution.    There are scientific developments in three fields that have already begun to influence us and together they will make enormous changes. I do not think we can stop these changes even if we want to but we should be prepared for them even though no one knows the full extent of the revolution that they are causing. They are in:

(1) Communication technology
(2) Biology and
(3) in physics.

  The new communications technology - itself deriving from applications of physics - ensures that anyone in the world with minimal equipment can be full aware of everything that is happening. All that he needs is a laptop computer with a satellite telephone line. Moreover that line will be more reliable than the existing local telephone service. We have, and use, technology to watch each other. It is hard to hide. Even 30 years ago a photograph of Moscow from a satellite 100 miles in the sky enabled me to count the number of people in line to enter Lenin's tomb. There is an inevitable openness that creates an interdependence which will affect all of our lives.

  We have sequenced the human genome. This will bring the opportunity to cure or to kill. Biological weapons are true weapons of mass destruction and must be controlled if the human race is to survive. We will probably soon synthesize cocaine substitutes which can be made cheaply and in facilities that are harder to identify than the poppy fields- just as the manufacture amphetamines now very easily. That will make the international cooperation on the "drug war" even more important. Anthrax is in the news today. But many more people have been killed by our failure to control drugs such as cocaine than by anthrax.  On the other hand we can also wipe out pests - such as locusts - which eat our crops. But only if nations cooperate. When Ethiopia had a civil war, cooperation was suspended and the effect on the neighbors- an increase of locusts - was pronounced.

  Physics has brought us in the last 50 years nuclear medicine, nuclear powered electricity but of course the atomic bomb. The world has fortunately recognized the supreme importance of keeping nuclear weapons in check. More nations have signed the non-proliferation treaty than any other treaty. By signing this treaty each state gives up some sovereignty and becomes dependent on the others. None of us would support self determination if that included a right to make atomic bombs and threaten the rest of the world.

  In another respect, globalization brings us few options. It is no use saying "stop the world I want to get off". But in addition to the economic benefits it brings the world troubles closer - and makes global terrorism, as distinct from local terrorism, inevitable. It will be now with us for ever so we had better understand it.

Which terrorists are evil?

 Almost 100% of Americans, including myself, supported President Bush in his aim to capture Osame Bin Laden and his followers.   Although we might not use the word ourselves, we all agree that their actions and the men themselves are evil.  Most other Governments in the world so agree also. Although the bombing in Afghanistan seems to be justified by the events of the week of November11th 2001, in spite of many peoples forebodings, there is still room for questioning the overall US war on terrorism. President Bush has called Osame Bin Laden "evil"  Also evil, and with more serious consequences, was Adolph Hitler. Bertrand Russell, a prominent pacifist in world war I, publicly stated that fighting Adolph Hitler and his Nazi gang was different from the German Kaiser in World War I since Adolph Hitler was evil. There is less international support for Mr Bush's war on terrorism when the aim is widened to include all terrorists. It then becomes necessary to understand who is a terrorist. There can be terrorists on both sides of a dispute. In such a case the world (probably through the UN which was set up for the purpose) might have to place itself in the middle with a risk of loss of life of personnel.  Getting rid of Hitler took 6 years and 70 million lives.  Hopefully the world can get rid of evil men a little more simply now.

    The Chinese regard the Japanese Emperor Hirohito as evil, especially for his direct involvement in, if not ordering of, the rape of Nanking in which 300,000 Chinese were massacred. Although I was aware of this massacre as it occurred, it was far away, and Europe had more local matters to consider.  I was also unaware until recently that the Emperor was personally aware of the massacre and could have stopped it, and that the hero of the 50 odd westerners in the Chinese capital who tried to limit of the massacre was the head of the Nazi party in China. Surely this tells us that one can find heros in most unlikely places. The American acceptance of the Emperor after 1945 was very puzzling to many people - especially to Chinese.

    Some people regard Saddam Hussein as evil.  But far fewer than regarded Hitler as evil. Nonetheless I remember a telephone call at the start of the Gulf war from a friend with an Iraqi diplomatic passport. "There are a lot of bright people in the world" he said. "Can't one of them find a way of getting rid of that man?". But the world could not get rid of Hitler easily either.   Hitler, Hirohito and Hussein had in common their stated aim of a greater Germany, a more powerful Japan and dominance of Iraq respectively. To western minds, Bin Laden has only negative aims - wanton destruction of society.  But I am in a western society and maybe he appeals to those who want to replace our western society with an eastern one that we in the west barely understand. To go further I now turn to the more traditional role of a physicist - particularly an academic one - to define the problem.

Definition of a Terrorist

  I like to go back to the Oxford English Dictionary.  As I do so I will ask a set of questions. The reader will surely notice that I have many questions but few (if any) answers. Indeed I do not expect anyone to agree with me, or each other, on answers to all of them. But they should be pondered by us all.

The first use of the word discussed was applied to the Jacobins in the reign of Terror in the France of 1795. "The terrorists, as they were justly denominated, from the cruel and impolitic maxim of keeping the people in implicit subjugation by a merciless severity" .

Another use was to the extreme revolutionary society in Russia and the implication of important people was known in 1905 "Several notables are believed to be more or less implicated in the acts of the Terrorists".

It was also applied (in 1866) to those in Ireland objecting to British rule: "Miss G...., daughter of a Wexford terrorist, directed many of the tortures which were so extensively practiced".

And in 1805 there were the religious terrorists: "some book of the religious terrorists which tended to infuse the alarm of foul perdition".

    These uses of the word terrorist all in some way apply to a person or people, individual or governmental, which terrifies people.  How did President Bush use the word terrorist in his speeches? How did we hear it? Mr Bush seemed to consider it applies solely to those who oppose the policies of governments or entities whom America (Mr. Bush) dislikes. In parlance today, as formerly, the word was used against any people, or a government that one did not like. The President of Pakistan took care to explain that he opposes terror in all its forms- by which I assume he includes oppression of a people by its government or an occupying government. I suggest that we all heard it in the way we wanted. However most people in the USA use the word only to describe actions we and our government do not like, and by extension actions another government does not like. But that leads to problems. I list a number of conundrums which list is, unfortunately, very far from complete.

(1) Was Hitler and his Nazis a gang of terrorists even though they were the legitimate government of Germany, originally elected by the people?  Were opponents of Hitler terrorists? Especially Colonel Von Stauffenburg who tried to assassinate Hitler with a bomb in a brief case?

(2) Were the Hutus in Ruanda terrorists even though they were (as we know) supported by the legitimate government in their slaughter of the Tutsis?

(3) Were the Young Turks terrorists when they victimized the Armenians in 1916? Or were the Armenians terrorists because they were not model citizens of the Ottoman Empire and would not be slaughtered quietly?

(4) Again, were (and are) the opponents of British rule (or Protestant rule) in Ireland (or part of it) terrorists?   Has the situation changed since partition was generally agreed in 1922?

(5) Is the government of Russia guilty of terrorism against the people of Chechnya (who have as much voting power as other residents of Russia) or are the radical Chechens guilty of terrorism against Russia? Or both?

 (6) Is the government of Sri Lanka acting like theJacobins against the Tamils of the north, or are the Tamils a bunch of terrorists to be tamed?

(7) Were the French fighting a terrorist group, Greenpeace, when they sank the ship in a New Zealand harbor? Or were they terrorists themselves?

(8) Was Oliver North a terrorist? He was arranging the financing of the Contras, a group opposing the legitimate Government of Nicaragua, for his own ideological reasons, and contrary to the explicit instructions of the elected US Congress.

 (9) When does a government using excessive force against a dissident group become terrorist themselves? Were the actions against the dissidents in WACO Texas, terrorist activities in the Jacobin sense or were they fighting terrorists? At least one American (Timothy McVeigh) thought the former and became a terrorist himself in response.

(10) Was General Custer fighting a band of Indian terrorists as he made his last stand, or were the Indians fighting an oppression worse than the French had experienced in 1795? I note that at the time most Americans believed the former. Nowadays it is politically correct in some circles to believe the latter. It is safe to do so, since the Indians are dead or cowed, and it costs nothing to do so.

(11) Was Castro a terrorist or a freedom fighter when he opposed the government of Batista? Are the people who oppose him terrorists, whether they live in Cuba or Florida? What about those branded by Castro as terrorists to whom the USA has given citizenship?  The US supported Castro's overthrow of Batista and supported those who tried to overthrow Castro. Is the US government merely against any Cuban (or Carribean or ...) government which doesn't toe the US line?

(12) Finally, I mention an issue which arouses more emotion and interest in the USA than most others. However a professional must not duck difficult issues. It is here that his professionalism can be most useful. Is the government of Israel a terrorist government because with respect to the Palestinians they follow (to quote the description of the Jacobins) "the cruel and impolitic maxim of keeping the people in implicit subjugation by a merciless severity"? Or are the Palestinians all terrorists because they belong to an organization opposing the present government of Israel and its policies and particularly in its early days, to drive them into the sea?  Although they believed that Israel imposes a ruthless occupation upon them? Are the Israeli actions justified because of Palestinian terrorism (or resistance) or unjustified because (according to many people) even the Israeli presence is contrary to US Security Council resolutions?

One man's terrorist is another man's freedom fighter.

    The expression "freedom fighter" has been used by those who argue that a particular group is fighting for the freedom of his country against foreign domination and oppression and that this somehow justifies any otherwise unpleasant act that he or she performs. This phrase needs definition more than most others but the definition is inevitably subjective.

    A leading theoretical physicist Professor Victor Weisskopf once (in my presence) corrected a Russian interpreter for referring to the October revolution of November 1917 as a rebellion. Rebellion according to OED is organized armed resistance to the ruler of Government of one's country. But when the rebellion succeeds, it becomes a revolution: "the complete overthrow of one's government." Likewise when a terrorist succeeds in his objective of overthrowing the established order, he is regarded as a freedom fighter.

    Clearly Jefferson, once a rebel, became a freedom fighter. Most people would not call him a terrorist because he did not engage in violence, although he indirectly urged it. However Jefferson did not, in his writings condemn terrorism.  In contrast Monachem Begin was definitely a terrorist organizer in 1945 when he organized various activities such as the blowing up of the King David Hotel in Jerusalem. But he later became leader of his country (Israel) which had become free and independent. Bourgiba was jailed as a terrorist by the British in Cairo, but later went on to become the first President of his country (Tunisia). Syria, Iran and Iraq were on a short list of States that the US State Department accuses of encouraging terrorism. Yet Syria supported the USA in the Gulf war and now has a seat on the UN Security Council.  Has Syria thereby stopped being a terrorist country? Or were we wrong in thinking it was one before?

    In addition to the present bombing in Afghanistan, Americans have to look back at their own history to grasp the complications of such a simplistic distinction.

  "Single acts of tyranny may be ascribed to the accidental opinion of the day; but a series of oppressions, begun in a distinguished period and pursued unilaterally thro' every change of ministers, too plainly prove a deliberate, systematical plan of reducing us to slavery".

    As I read these worlds aloud a listener thought that these might be the words of Gerry Adams - the leader of the IRA. But they might also be the (translated) words of a Kashmiri leader, or of Yasser Arafat. But no. These words were written by Thomas Jefferson in 1774. They propelled him to the Congress in Philadelphia as a representative from Virginia. Jefferson was clearly accusing George III of the form of terrorism according to the usage I listed first in this memo. This was before the Jacobins came to power and the word "terrorist" became popular.

    Indeed on July 4th every year Americans celebrate the day when terrorists became patriots and rebels became statesmen.

I then go on with my difficult questions.

(13) Were the perpetrators of the Boston Tea party "terrorists" as George III might have said, or freedom fighters? They wantonly destroyed private property but they killed no one.

(14) Almost everyone in the USA and many others seem to agree that the people who deliberately flew airplanes into the world trade center were terrorists. But the further one gets into the complicated disagreements, the more difficult it is to agree upon a consistent definition.

(15) In May 1940, after Dunquerque, most Englishmen feared a Nazi occupation of England within a few weeks.  Teenagers, including myself, learned rules of unarmed combat. While before 1939 we had been taught the "Queensbury Rules" of boxing, we were now told:"always hit below the belt" and "stamp on the instep". I was shown how to creep up on a German sentry and cut off his head with a sharp wire such as used for cutting cheese. Was this education in resisting unwanted occupation a training in terrorism or training in fighting for freedom?

(16) The birth of Bangladesh 30 years ago illustrate show how a metamorphosis can come about.  Some people in East Pakistan picked up guns to oppose the government of West Pakistan. They were clearly terrorists. As the weeks passed they became freedom fighters. When they succeeded they became the first statesmen of their new country.  But the Pakistani Army objected even as they were losing. On December14th, "Martyred intellectuals day", the Pakistani army systematically slaughtered hundreds of intellectuals: judges, lawyers, physicians and professors. Such behavior, disguised to appear as a legitimate and proper response to those trying to destroy law and order can also be assumed to be a deliberate attempt to deprive a new nation of its leadership, is all too common and can be seen today.

 How Does one Choose Sides?

    Opinions of people will differ on each of these cases, and few will come out on the same side on all of them. But we can probably all decline the irregular verb and say literally:
"I am a statesman
You are a freedom fighter
He is a terrorist"
(A) As Dr Elena Bonner said about the fighting between the Armenians and the Azeris in the early 1990s, both sides did bad things but (in her view) the Azeris were bad first because they massacred ethnic Armenians in Sumgait just north of Baku. But is that enough reason in itself for choosing sides? If not what are the criteria? Nowadays, in the USA, the distinction tends to be made between individual terrorism and state sponsored terrorism although the President of Pakistan (among others) recently insisted that he opposed both equally. Most Americans seem to think that only the former (individual terrorism) exists even though the word seems to have been first applied to the state terrorism of the French Jacobins, and the much support for the IRA in Ireland against the British came from the USA.!

(B) The late Edwin H. Purcell, Nobel Laureate in Physics and for six years a member of the President's Science Advisory Committee, used to describe his view of the US administration's position (which he opposed, particularly as it applied to Vietnam): "A terrorist is a man with a bomb and no airplane to drop it from".

(C) This talk was first given in Chatham House where William Pitt (the elder), Earl of Chatham, once lived. After a distinguished period in office, George III replaced him as prime minister. Chatham said in his last speech: "My Lords, if I were an American, as I am an Englishman, while a foreign troop was landed in my country I never would lay down my arms- never, never, never." I would not rest until the last foreign soldier had left my soil". I commend these words to statesmen in any country whose troops are on the soil of another.

The Planners and Financiers of Terrorism

    It becomes even more complicated when one discusses the planners, and financiers, of terrorism. President Bush explicitly stated that he would consider them equally. If we take the implicit modern American usage of a terrorist who opposes by illegal force, including attacks on civilian targets, the established government President Bush must clearly oppose strongly (and even prosecute) the IRA and its financiers, widely believed to reside in Boston and New York.  Fortunately the IRA seems to have got the message (although in September 2002 Mr Trimble and others claim that it is not disarming but should do so).

    President Bush has frozen the assets of Hezzebolla because he claims that it is a terrorist organization. The Lebanese government has stated its reluctance to do so. Hezzebolla, in the Lebanese view, are freedom fighters trying to liberate southern Lebanon.   Which is correct?  Will we have a situation where many organizations have assets frozen in one country but not another? and particularly not in Switzerland or the Bahamas?

    Some observers (e.g. Baroness Cox) have noted that financiers with contacts with Al Qaeda, own major blocks of shares in companies in sensitive positions in western countries. These holdings clearly have the potential to cause great trouble. Far worse however, would be secret dealings. Indeed it is hard to see how one can have anything approaching global security with the secrecy of the tax havens so many countries like and economists have been slow to oppose. I believe that strong international agreement to prevent tax havens is very important. In the wake of the Enron, Anderson and Worldcom scandals, maybe the US congress will muster the courage to propose such a step.

  Civilian or Military Targets?

    Many people with whom I have discussed this issue claim that attacks on civilians break the important barrier that distinguishes a real terrorist from a justified freedom fighter. Some would add the adjective "unarmed" before civilians. Some would add: "with intent to kill". According to this view an attack by an individual against an occupying army or police would not be a terrorist attack, but would be justified resistance. But that leads to problems also. The Boston tea party perpetrators and the Palestinian youth who threw stones at soldiers would clearly not be terrorists according to this definition. But would the Palestinians be terrorists if they threw stones against Jewish worshipers in Jerusalem even though there was no intent to kill? What about bullets against armed settlers even though, according to their contention and belief, the settlers had stolen their land? When applied to state actions, such a definition would have to apply to many more actions that are often accepted. Were the air raids, primarily against civilians in Dresden, Hiroshima and Nagasaki in world war II justified or were they unacceptable state terrorism? What about the actions of a country (USA) that anticipates and accepts "collateral damage" in Vietnam and Afghanistan? 

    Finally, during the cold war, the USA and the USSR could be said to have terrorized each other by the policy of Mutually Assured Destruction (MAD). It was mad indeed. My family and I were scared at the time of the Cuban missile crisis when the USA had about 70 nuclear weapons and the USSR had about 40. If 40 bombs is enough to deter a people (if not their government) why did we make so many thousands of bombs? And what is the merit in reducing from 5,000 to 2,000 as is now being discussed? Even 2,000 is far more than necessary for the stated purpose of terrifying another country.

    Much more important is the question: are not both the USA and Russia terrorizing the world by keeping even 10 bombs on dangerous "trigger alert"? Dismantling the bombs so that their use would require 3 days notice would avoid destroying the world accidentally by mistakes such as that of 1995. Why are not Bush and Putin both evil for refusing to follow the duty under article VI of the non-proliferation treaty and dismantling the nuclear bomb arsenal completely?

    Indeed I blame both Mr Putin and Mr Bush for signing the recent agreement on nuclear arms. It is a step back from the SALT2 treaty we signed but never ratified. It allows nuclear weapons to be decommissioned rather than just destroyed. It reverses the 30 year old ban on weapons defense. Perhaps the saving grace of the last is that most scientists agree that the "Strategic Defense Initiative" will never work. However it can be a "cover" for other weapons activities and give a very dangerous false sense that there is a technical solution to a problem that is a permanent political problem; one to which we must pay attention until the end of the human race.

Cowardly acts

    I emphasized the importance of definitions and in particular the importance of using words so that they may be understood. Sometimes, of course, politicians deliberately use words in ways to confuse. A professional should not accept this. The complications also enter when the adjective cowardly is carelessly used, particularly when attached to the noun terrorist. It has become all too usual to describe "suicide bombers" as "cowardly". I first heard this word when General Haig described the man who drove a truck full of explosives into the US Army barracks in Lebanon as a coward. Although Humpty Dumpty said "I pay the words extra and make them mean what I like", I believe that this is NOT a useful use of the word coward. By its' pejorative meaning, it tends to prevent the listener from thinking about the root cause of the action being discussed. But it has been used again and again recently.

    But were the Japanese Kamikaze pilots in world war II cowards, or misguided patriots? I believe that Colonel Claus von Stauffenburg was a brave man as he carried his briefcase bomb into the conference room with Hitler. He is reported to have said after gaining access to Hitler's briefings: "Fate has offered us this opportunity, and I would not refuse it for anything in the world. I have examined myself before God and my conscience. It must be done because this man [Hitler] is evil personified."  But Colonel von Stauffenberg became a coward when, and only when, he refused to stay with the bomb to ensure its success. He was also careless. He was outside when the bomb blew up and left.  When Hitler came staggering out he could easily have been killed right then.

    Who were the greater cowards: the Israeli pilots who dropped bombs on the UN refugee camp in Lebanon from a safe height, or the Palestinians who chose certain death to ensure the killing of people, including a dozen unarmed civilians, in Israel? Does it make a difference that the Israeli government apologized for the mistake (but without paying compensation) in the first case, whereas a number of Palestinians were jubilant in the second?

    Historically countries have romanticized war.  The bravery of the soldiers was extolled: one who refused to go into battle was labeled a coward.  The bravery of one's adversary was acknowledged even as he was being killed.  In my boyhood I saw several films and read books about world war I, and how the British Air Force in particular, honored the bravery of the German pilots. This romanticization of war has, I am glad to say, gone out of style and the demonization of an individual adversary, particularly a weaker one who fights in a different way, has replaced it.  The replacement sentiment is, I believe no better, and is perhaps worse because it is a negation of thought.  An ABC talk show host was roundly criticized for making some of the above distinctions in late September 2001. That makes the situation even sadder and even more dangerous.

Defense in Depth

    This was a long time in preliminaries. But the preliminaries are essential to be sure that we are talking about the same subject. I now come, at last, to the three independent steps that I believe to be essential if we wish to combat terrorism. As is usual in discussions of series of events, it is easier and more important to address the first step in the chain.

Step 1: The root causes of Terrorism

    Terrorism has been with us for centuries and seems to be a permanent facet of our existence.  I therefore think it is very important to attempt to find, and eliminate or reduce, the root causes of terrorism. Among these root causes are clearly frustration and despair caused by poverty, hunger, ignorance, injustice and intolerance. In the various long run disputes that plague the world, most people are not armed; and believe in peaceful solution to problems.  But w hen oppression becomes, or is perceived to become, intolerable, these peaceful people will refrain from denouncing those that take up arms in their cause.  These that are killed while fighting become martyrs and are honored.  It is not hard to see that these "freedom fighters" can go over the edge. Terrorism then becomes an end in itself independent of the cause.

    Terrorism has been described as a cancer on our society. If we develop the analogy further, I note that cancers can be controlled and even cured until they metastasize to another location. When IRA terrorists, now seemingly, and most of us hope permanently, unemployed as terrorists at home, started training terrorists in Columbia, such metastasis occurred. Many of us fear a metastasis of the Palestinian/Israeli conflict.  Indeed one Israeli foreign Ministry representative, talking in February 2002on National Public Radio, implied that metastasis had already occurred by blaming the Palestinians for setting a bad example to other arabs. Most of us agree that these long running disagreements can be a breeding ground for terrorism.  Edward Rothstein, writing in the New York Times of November 17th 2001 seems to dispute this but that may merely be his interest in a particular case.  When disagreements are also seen, or perceived, to exist side by side with wealth, extravagance and aggression of another group, particularly an oppressing group, there is likely to be trouble.  In my view the solutions must lie in charity, tolerance, and humility in understanding and helping other peoples.

   To this end I have circulated the following statement and encourage others to support it:

"We at (state your group), a diverse community of many races, religions, cultures and nations, commit ourselves to work for peace and justice everywhere in the world. We invite others to join in this commitment.  We must and will fight ignorance, poverty, hunger, intolerance and injustice wherever and whenever they show their ugly faces. We must succeed so that no one state, no one group or even one individual will ever again have the desperation to perform such an abominable act as the attack on September 11th 2001 or shelter one of the perpetrators"

    I have no patent on this idea, and indeed it is very similar to one the citizens of the city of Hamburg in Germany adopted in 1998.  I would be grateful if any group decides to say the same would let me know. It is, however, difficult to put the aims of the perpetrators of 9/11 in the categories above. The perpetrators were Egyptians and Saudis. Surely not countries being (directly) oppressed by another country. But many analysts have noted that these two countries have governments that are responsive to the needs of the rich but not of the poor. They also leave little room for the poor to express themselves politically. There is no opposition party in the western sense. The poor, and the middle class people who support the poor seem to have no option but to turn to organizations such as the Moslem Brotherhood (in Egypt) who seem to have people dedicated to help the poor. Both the people of the USA and their governments prefer to deal with a stable, even though undemocratic, government than one in political turmoil. The US government supports the governments both of Egypt and Saudi Arabia; providing aid in the former case and protection in the latter. This automatically makes the US complicit in the government's actions and a target for those (the suicide hijackers and Bin Laden) who object. There is no easy way out. The USA gave strong support for President Syngman Rhee of South Korea, and we were fortunate that the Koreans eventually made their own internal reforms. The recent attacks were clearly against symbols of America's domination: the pentagon with its military domination and the World Trade Center with its financial domination. I think that it is important to note that they were not against other targets in America which, as I will discuss later, could do much more damage to US civilian life.

    There is an interesting cheerful corollary to the above thought. The population of Iran has more than doubled since the Shah was overthrown and the clerical government took over. A majority of the population is under 30 and never knew the Shah. These are the young people who might engage in violence. Yet their frustration with lack of progress of the country seems to be aimed at their government not at us. For the USA can hardly be blamed for supporting the existing, clerical, government. To the very limited extent that President Bush is correct in calling the government of Iran as evil, this does not seem to apply to the young people.

Step 2: Keeping Terrorists at Arm's length
(some would add an intermediate stage- keeping weapons out of the hand of a terorist)

    I believe it would be stupid to believe that one can correct all the root causes of terrorism, and perhaps not many of them. The consequence, then is that there will be terrorists who must be contained, isolated or eliminated (killed).  In the immediate aftermath of the World Trade Center destruction, President Bush assembled a truly remarkable coalition of world leaders to denounce terrorism.  One must not belittle the importance of this achievement by comments that many of them are not leaders of democracies, or are in some way oppressing other people. Some of the most emotional support for America has come from people from other countries who are trying to build American values in their 3rd world countries. Yet there is a perception that American actions do not always follow the stated ideals.  Palestinians and nearby Arab states, for example, complain that the US government continues to subsidize, and provide arms to, Israel regardless of what Israel does.   Indians complain that we fail to denounce the failure of Pakistan to halt terrorism in the Kashmir.

    There is general agreement with Jefferson's concept that "no society can survive without a decent respect for the opinion of mankind."(quotation from memory). This unanimity in the world is probably greater than at any time since 1945 when several unlikely major countries were allies against the scourge of Hitler. We must capitalize on it. In this context I commend and support a fine op-ed piece in the NY Times by Mikhail Gorbachev who argued that we had setup an organization in 1945 to cope with matters such as this and we should use the UN. But of course we should not hesitate to modify it if necessary.   Indeed I believe that modification is appropriate.  In the General Assembly the voting power of populous countries like USA, Russia, China and India is no greater than the voting power of the many small countries, and this has led both USA and USSR to avoid taking to the UN issues of importance to Russia or the USA.  Something must be done to avoid this international impotence.

   While almost all of us believe that religions have played a major part in making the world a better place for its citizens, there is no doubt that wars fought in the name of religion, particularly in the crusades and the wars of the 17th century, have created major havoc. Thus has been built the concept of religious freedom and the vital importance of toleration for the religion and opinion of another. But there are limits to toleration. Society cannot survive if it allows the extremists of any religion to attack others. Most Moslems might insist that "jihad" means an inner struggle. The capturing or restriction of the word to mean armed struggle against another person is already a sign of trouble and western society has become wary of groups such as "Islamic Jihad". The defining and enforcement of these limits is one of the most important problems of this second step in combating terrorism.     More recently we learn (e.g. interview with Kuwaitis on "60 minutes" on November 18th 2001) that the world is not unanimous and that support for the US may not be as firm and strong as desired.  In my view that is partially because the US has not faced up to the difficulty of defining terrorism, and modifying its own thoughts on the contentious issues mentioned earlier to more nearly accord with international views.   It is urgent for all people of good will to discuss these issues.

    Finally I believe that although the UN has been wise in restricting its actions to internal rather than domestic problems, (because otherwise it would be overwhelmed), I believe it must intervene and act and act firmly, with justice and generosity, in any conflict that has existed for more than 50 years. These include Ireland, Sri Lanka, Kashmir, and of course the Holy Land. If the world waits the wound to society will fester.

Step 3: Making Society Safer

    America is an extraordinarily safe place - although there is a higher murder rate in America than in England.   My father's house in London was robbed 3 times in 25 years. My house in America has never been robbed in 46 years, although we accidentally left the doors unlocked for a month during one vacation. That is, in fact, one reason why the 2,800 people killed in the World Trade Center attack was so troubling. It is here that President Bush has paid most attention, and created the Office of Homeland Security. It is here that Risk Analysts such as those who go to PSAM6 meetings can and should provide the most help. The problem must be considered carefully.

Postmortem on the World Trade Center

    Worrying about the world trade center is somewhat like fighting the previous war - with all the strategic mistakes that trying to fight the last war encourages. Nonetheless I start with my own postmortem on the world trade center collapse. I have read and recommend, the report in May 2002 of the Federal Emergency Management Agency (FEMA) and also an important factual paper, "The World Trade Center Catastrophe: Was the Type of Spray Fire Proofing a Factor in the Collapse of the Twin Towers", by Dr Arthur M. Langer and Dr R.G. Morse which appeared in the July 2002 issue of the Journal of the Indoor and Built Environment. As I read the FEMA report I believe it missed the major conclusion. Although the building was a strong building, and built according to code, no one in the building industry, had considered what Norman Rasmussen emphasized. This is what safety analysts such as the participants in PSAM6, consider everyday: the low probability high consequence accident. A terrorist will consider a high consequence event- and convert it from low probability to high probability. We must consider such accidents in advance of the terrorist and make our society as secure as we can. In that we have available the tool of the event tree. I n this connection I note one paper that was presented to the 2002 PSAM6 conference, Dr Christie and collaborators. If a full risk analysis is made, including full attention to the non safety related procedures, a nuclear power plant has a fatality risk that is 30 times smaller than if the plant designers and operators merely meet codes and NRC regulations. That probably applies all over society. My major conclusion is that the building industry, as all other industries, MUST do a full event tree analysis and pay particular attention to high consequence events.

    There are smaller problems with the FEMA report. Steel buildings, and in particular steel supports are more vulnerable to fire that concrete or even wood. US builders may not have understood this, but the captured tape that was released on December 14th 2001 showed that Osama bin Laden understood it well. Steel conducts heat more readily, and can bend and melt at fire temperatures. At the World Trade Center the steel uprights and horizontal floor supports were originally planned to be insulated with asbestos to retard fire. Langer and Morse suggest that the inferior properties of the fiberglass insulation as compared to asbestos was an important issue, in the collapse. Certainly the insulation did not stick to the beams at the time of collapse. These authors suggest that the material was sprayed on steel beams that were rusty and the material may well have peeled off again. Electricians and members of other crafts often scrape off insulation to install their own devices. Some photographs of the fallen beams suggest that, indeed, many of the beams were denuded of insulation. It appears that no one checked that the insulation was secure after the other construction trades had done their worst. There were no enforced regulations at the time. It is possible that if the original asbestos had been used, or the building redesigned, it would be standing today. It is irrelevant whether Langer and Morse are right. What IS relevant is that no one seems to be able to disprove their suggestions. This suggests that any and all tall buildings built at that time be checked in detail to see whether the insulation is still present.

    My colleague Dr Pompei suggested a simple method. Test the insulation by a reverse process. Apply heat to a steel beam at one location, measure the temperature at all nearby locations and compare with a calculation assuming that all insulation is in place. This might cost $50 million per building. But that is cheap compared with bombing Afghanistan.

    It is also not correct that no one raised a warning. The man who was most responsible for the use of sprayed on asbestos, the late Mr Herbert Levine, founder of Asbestospray, was concerned. He told anyone who would listen (including me in 1991) that "if a fire breaks out above the 64
thfloor (where asbestos stopped) the building will fall down." This raises another question. Should one pay attention to every warning? I suggest that this warning was a warning of a vulnerability that should have been examined. 
    Again nothing is perfect, and we should have had defense in depth. Evacuation of people in the anticipated 4 hours time available in which the fire resistant material would last was foreseen and indeed evacuation occurred to a remarkable extent, but not everyone would get out, and there was major property damage as the buildings fell. Many disaster movies have shown helicopters picking people off the roof of a burning skyscraper, and spraying foam into the fire below. Where were the helicopters on September 11th? Were there any disaster plans? Clearly any new tall building should have had, and must now have, plans to cope with such disasters and must take account of events of low probability and high consequence.

    Buildings can be protected from airplane attacks.  In world war II cables were hung from barrage balloons to cut off the wings of any aircraft willing to fly into them. Sensitive facilities at Los Alamos are protected by cables hanging from tower - no more conspicuous than cell phone towers.  These would not completely protect against air attack, but the probability of serious consequences would be diminished.

 Although most of the public discussion is about preventing an accident of the same type as occurred on September 11th I believe that it is unlikely that it will be attempted again soon. For the last 10 years airplane hijackings have been handled peacefully by the pilot following instructions of the hijacker and arguing (negotiating) when the plane has landed.  Pilots basically "gave in". After September11th that has clearly changed.  Pilots will obviously resist even though the probability of a terrorist being a suicide bomber is probably small. As we saw, the consequences of a successful suicide hijacking are large. But there are a number of technical steps that can betaken. They have even been suggested and put aside. Barring the cockpit door is obvious.  The pilot could have a special button that a pilot can press to alert FAA of a hijacking just as bank tellers alert police by a button when a bank robbery is in progress.  It is also possible to set by such a button, or by command from the ground, a preset flight and landing pattern. These have their own possibilities for sabotage, but there seems to have been no study and discussion.

The General Vulnerability of Society

    It takes very little thought to realize that society is very vulnerable to sabotage and terrorism. But it can be made more secure. We could start by taking basic safety precautions. There is clearly potential for a terrorist to cause great harm by making sure that we do not store a lot of fuel in one place nearby a lot of people in one place. Oil tanks and Liquefied Natural Gas (LNG) facilities should be in remote areas.  In my opinion it is more important to locate such sensitive facilities in remote areas than it is to locate nuclear power plants in remote areas. I commend the citizens of London who, a century and a half ago in 1848, decreed that petroleum products not come up the river Thames closer than 30 miles east of London bridge. The accumulation of over one hundred 17 million gallon tanks (LNG, oil, ammonia) in Canvey island (30 miles east of Tower Bridge) was not good. That planners allowed seaside vacation bungalows to be built at the east end of the same island, with two bridges to the mainland converging on one traffic circle (roundabout) was NOT good. It prevented evacuation if trouble occurred whether caused by the IRA, Okaeda or the Tamil Tigers. But the decision of the UK government to ask the Atomic Energy Authority experts in Risley to carry out a safety analysis was excellent. Their (1978?) report, CANVEY, to the UK Health and Safety Executive is an excellent example of clarity of thinking and exposition. One can doubt their numerical assessment of safety, particularly because they did not address international terrorism although they addressed sabotage; but it is hard to doubt the improvement that addressing their simple improvements achieved. But few localities have been as cautious as the good citizens of London 150 years ago. I give here a number of examples in my personal experience and knowledge of how this simple rule is frequently violated.

Fuel storage:

    Co-location of long unprotected rail, gas pipe and water pipe lines is a recipe for disaster.    I am well aware of the financial and social advantages that using a common, already paid for both politically and financially, right of way can afford, whether in a capitalist country or one with a "centrally planned economy".  But we only have to look at the Soviet LPG accident in the late 1980s,when a gas pipe line leaked and was set alight by a couple of electric trains on the co-located railroad to see the problem. In this little publicized accident 800 people were burned to death - far more than Chernobyl yet with less international publicity and consequent domestic concern.  In the USA, an overloaded freight train derailed in Cajun Pass and broke the accompanying gas pipe line which later exploded- killing 2 people.  This has always seemed to me fruitful ground for a terrorist - and terrorists like Osama Bin Laden are now more intelligent than many politicians.

    In 1972 or 1973 I had a phone call from a distraught resident of a suburb of Providence, Rhode Island. The local gas company was planning to put a big multimillion gallon LNG storage tank 500 feet from a local school. There were other sites. One obvious one was ruled out because it was 500 feet from a power line (surely less important than a school). I gave testimony suggesting that there was inadequate caution and was on the witness stand for 6 hours. But the local residents won. In 1975 I reviewed a risk assessment for an LNG tanker terminal on the west coast near a major city. The calculated risk was small (10^-35). But the study had had left out sabotage or terrorism where the risk is unfortunately much bigger.   I pointed this out to a director of the gas company who had paid $1,500,000 for the study. I suggested that he rethink the conclusions. If he used the study to justify building the terminal I could (and might well) destroy him.

    The methane in an LNG tank only has to be mixed with easily available oxygen to be highly inflammable and in some circumstances explosive. In contrast neither the fuel itself nor the stored fuel in a nuclear power plant is easy to sabotage in the same way.  In Boston there are two 17 million gallon tanks within 2 miles of the center. If mixed stochiometrically with air each would have the energy content of 3 Hiroshima bombs. 25 years ago I participated in a study for the General Accounting Office (GAO) and in a session deliberately unrecorded, we found many ways to wreak a lot of havoc. These scenarios were deliberately not written down and will not be here. Suffice to say that a week or so later, I stopped for coffee along the Massachussets turnpike and found three trucks side by side at the rest stop. One was a gasoline truck. Another a liquid oxygen truck. A third was an LNG truck. I went on to the next rest stop. We must now pay close attention to these events of low calculated probability but high consequence. The terrorists will.

Hydroelectric Dams

    Hydroelectric dams are necessarily upstream of an estuary. For reasons of easy communication, by sea, society has usually built a town at the estuary. Hydroelectric dams have sometimes given way naturally, and at one time the "natural" failures made hydropower one of the more dangerous energy sources.  Natural failures have been reduced, but few analysts have considered sabotage.  In 1944 an Englishman destroyed a hydroelectric dam in Germany under very unfavorable circumstances. He had to do so from the air (with a 7,000 pound bomb) while being shot at from the ground by merciless antiaircraft fire.  This was documented in the film: "the dam busters". With more modern explosives, this could be done with a 1000 pound bomb from the ground. To test the possibility of this route of sabotage I deliberately drove out onto an unguarded dam in the upper Connecticut river, stopped long enough to take such a heavy object from my car and drove away. No one said anything.  The late Professor Arthur Casagrande, one of North America's major dam designers, told me 30 years agothat if a dam in the upper Missouri were to fail naturally or be destroyed deliberately in time of flood, then all the dams downstream would fail until near St Louis, where he had deliberately designed a dam to cope with such a contingency. At the Connecticut River we both had little doubt that if I had blown up this dam on the upper Connecticut in time of flood, all dams would fail in turn down to the sea. After I related this story at the PSAM6 meeting, a risk analyst in the audience told me that he had studied the risks of all of these dams for an insurance company but had failed to consider that these failures might be correlated (common mode failure).

Anthrax and Smallpox

    The anthrax scare was technically easily avoidable. Surgical equipment in hospitals is sterilized at modest expense, by gamma irradiation. It would not be unduly expensive to pass ALL mail in a sorting office past a cobalt 60 (or cesium 137) unit, that sterilizes everything within. Society might decide that this would be undesirable as a general rule. It would stop my wife sending flower seeds to our children through the mail. But the equipment could be ready to be used immediately on the first outbreak. Indeed this seems to be happening. A smallpox scare could be worse since it is airborne. Vaccinating everyone might be a solution, but this would subject everyone to a risk, about one in a million lifetime risk. Experts now recommend that vaccine be made and stored but used only after an initial outbreak isdetected. This is an interesting recommendation because it is a clear risk-risk comparison of the type that the probabilistic risk analysts at PSAM6 always recommend.

Agricultural Chemicals

    We did not learn as much as we should have from the Bhopal accident in India where a lot of isocyanate, used as an intermediate in fertilizer manufacture, was stored in one place and housing was allowed to be built nearby. I tend to believe the claim by analysts at Arthur D. Little that the release was deliberate sabotage by a disgruntled employee. But the designers and operators of the plant were delinquent in may ways. They designed a plant which was easy to sabotage; the stored more isocyanate in one place than they needed; they allowed people to live nearby, and they failed to train the employees and community in the simple precautions (put a wet handkerchief over your face).

  Ammonia is used as an agricultural chemical intermediate and used to be stored in large tanks - 17 million gallons - often close to a community. If released over a residential area there would be a large loss of life. The day after Iraq invaded Kuwait both my friend Dr Adnan Shihab Eldin, former director of the Kuwait Institute of Scientific Research, and myself remembered that there was a large ammonia tank in the port of Shuwaikh only 1/4 mile up wind from a population area. I don't doubt that this would have been released, when the wind blew in the right direction, to add to the mess created by the oil fires. We discussed how to get someone to empty the tank. We later found out that a Kuwaiti who was in the country at the time had had the same thought and emptied the tank into the sea while telling no one.

    Timothy McVeigh took advantage of easily available fertilizer, ammonium nitrate, to fashion an explosive that destroyed a building in Oklahoma city. This fertilizer is still easily available. After the Oklahoma bombing, Russell Seitz suggested at a Congressional hearing that all agricultural fertilizer be mixed with urea - to make it impossible to detonate. But farmers object because it makes the fertilizer stink. Maybe this should be reconsidered.

Drinking Water

    Drinking water supplies can be easily contaminated and even the threat of contamination can upset a community. As a beginning graduate student I had to do some silver plating with silver cyanide solution. When I got a headache I looked up the poisonous properties and realized that I had enough cyanide in the cupboard to poison the whole city of Oxford. Of course this last remark is about as useful as the oft repeated remark that a kilogram of plutonium could poison the world. The poison would have to be spread uniformly. But I went on and found out exactly where to drop the material (from a small footbridge) to do the most harm The Oxford water supply system has been upgraded but similar problems remain. Most water systems can be easily sabotaged. But the solution is simple. A state can make available a portable system that could be rushed to any threatened system to provide emergency water. Such systems exist: they could provide 10,000 gallons a day at a cost (including paying off the loan) of 1.5 cents a gallon - somewhat cheaper than the bottled water many people store for such emergencies.

Nuclear Power Plants

   There has been recently a lot of public attention paid to possible accidents in nuclear power plants. plant safety, including accidental aircraft hits.  Now they must be specifically applied to possible terrorist attacks. Yet few other facilities are studied with the same thoroughness. In this, we can thank one again those who made the decision 40 years ago to build strong containments. The record shows that these are among the few facilities where sabotage has been considered, and even direct hits from large aircraft. Those close to airfields (such as Seabrook NH) are designed to withstand a crash of a Boeing 747at 500 mph. Others will withstand a large aircraft at landing speed (200mph) but even if parts of a faster plane penetrates the containment, there is no reason to believe that such a release could be large. A direct hit from a large aircraft could put such a power plant out of action - maybe for ever, the most important issue for public confidence is the possibility of radiation release.  The probability of release is hard to calculate, and the Nuclear Regulatory Commission is rightly reexamining the issue as a matter of urgency. One matter is clear: hitting the containment vessel will not cause the worst accident. 20 years ago I discussed sabotage with Norman Rasmussen. "It is hard for a saboteur to do more than the clowns at Three Mile Island did on their own." But the probability can be increased. Many in this audience know better than I that there are some places an airplane could hit that might cause real trouble. But do not tell me - except in general terms. I might tell a terrorist by mistake. Fortunately hitting some spent fuel in its storage casks will not do asmuch as many people fear. The casks are hard to break open; almost impossible to burn. There is no radioactive iodine left, and it is hard to vaporize the fuel.


    The above examples focused on actions that can cause death. But even actions that cause no casualties can be As I reminded NAE, a simple relay failure started the sequence of events that led to the blackout of the northeastern United States in 1966 (or maybe in was1965). A saboteur could do this - but he would have to know what relay! But a terrorist group may well be diligent enough to find the weak link.  A single substation failure at Naperville, Illinois shut down the landing control system for O'Hare airport (AND, more important to me personally, shut down the E mails from my son at FERMILAB.

What should we do?

    In all the above examples most elements of society have not even begun to think about the societal vulnerabilities that exist. Firstly society needs to consider the most elementary precautions using the "defense in depth" philosophy. Then we can use the full panoply of techniques to assess the relative vulnerabilities of different parts of society. We can, and should, study sabotage and terrorism with the imagination (perhaps the imagination of a physicist) which we apply to other potential accidents.  We should imagine what a terrorist might do and then devise a system to make it hard for him to do it. This is the "defense in depth" and the "Event Tree Analysis" that are already successfully applied to nuclear power as nuclear power plants.   We must imagine what a terrorist might do, make it unattractive, and also make the consequences low. This should be done in a comparative way so that excessive resources are not spent on one vulnerable point in society to the exclusion of all others.  The actual risk that a terrorist poses is hard to calculate. We may therefore need an intermediate goal ,in the same way that NRC has an intermediate safety goal for US light water reactors; the reduction of core melt frequency to less than 1 in 10,000 per year. I suggest that assessed vulnerability could be the basis for such a goal. The Department of Homeland Security has been created and is being funded. It is our job to influence that department and to make sure that they use the best techniques that we can offer. In that direction, why was not the head of that department come to this particualr meeting? Was he invited?  (The answer was no)

    But we should be a little careful about doing too much. I understand that New York State has taken a lot of map directions off its web sites to avoid giving easy instructions to a terrorist. This is reminiscent of May 1940 when all the (road) signposts in England were cut down in anticipation of an imminent German invasion and the state controlled terror that we all anticipated. Such actions will make a terrorist's life more difficult, but may not reduce the probability of his success by much. In performing them we should be aware of Edward Teller's most frequent recent utterance; unnecessary secrecy harms society more than it harms the would be enemy, whether state, saboteur or terrorist.

    Sabotage and terrorism are unfortunate facts of life. They will be with us until the end of the human race. Indeed, if we do not pay attention to them, there may well be a premature end to the human race.  The countries of the world must get together and pay attention to the three facets above. We must resolve conflicts and situations that breed terrorism, isolate the terrorists, and make modern large scale technologies ever more difficult to attack.

    Until recently America only experienced random, uneducated, terrorists.  Until 1970 few experts thought further. But in 1970 it became clear that there could be educated terrorists with a"cause". These educated terrorists might take a reactor safety course at MIT to learn the weak points of a reactor, or my "Risk Analysis" course to learn all sorts of risky technologies that could be disturbed.  But I thought that 19 terrorists acting in concert was very unlikely. I was wrong, and all of society must now recognize that the probability is, alas, quite large.

    Those who have been unable to get public attention properly latch on to any seemingly related event or idea to raise their unheeded concerns.  I am among them. I am, therefore, in delighted agreement with the general idea that there is now MORE emphasis among the US public on considering the dangerous proliferation of nuclear weapons. In that sense 9/11 may have been a blessing in disguise. 9/11 was a "wake up call" to America.  Just as Chernobyl may have been a "wake up call" to the USSR and a blessing in disguise. Marshal Yazov, defense minister of the Soviet Union, at a small meeting in his office in May 1991 stated to a small group of us that the Chernobyl accident persuaded hard line Soviet generals that a nuclear war could not be won.  "If a reactor that was not supposed to explode made this much mess, a nuclear war would destroy the planet".  I have worried about nuclear weapons proliferation for 50 years. I have worried about biological weapons for 40 years. I have worried about chemical weapons for 60 years since I was trained to cope with them in world war II. However, although are very nasty, chemical weapons are not really weapons of mass destruction in the same sense. But on issues of weapons of mass destruction it is not enough to raise concern in the State Department. Concern about proliferation of weapons of mass destruction must be raised in every citizen by instruction in every school, not only in the USA but all over the world.  Mankind has a capability, which since 1945 has become very clear, of destroying itself completely.  Indeed, from a technical point of view, destruction of the human race by these weapons of mass destruction seems far easier than planning for the continuation of the human race. A terrorist may prefer to destroy the human race. Most of us prefer to plan for its continuation.. But it is not enough to prefer it. We must think and act. As scientists said loudly in 1945 - everything (technically) has changed but our ideas have not.

Comparison of Risks

     I frequently urge that everyone would gain perspective by comparing the risks of the activity one is considering with other risks which may be more familiar. I believe that it is useful to do this for terrorist activities.

    2,800 people were killed at the World Trade Center. This was indeed terrible. But over 40,000 people are killed every year on US highways by automobile and truck accidents. Is this not more terrible? Yet somehow it does not seem so. I can identify two aspects which account for the difference. Firstly, a large number of people killed at the same time is psychologically more disturbing than the same number of people killed over a period of time.     This seems to be true of other accident situations.  Secondly, terrorism and the fear of more, even worse, terrorism seems to be even more disturbing than an accident of equivalent magnitude. Analytically, in a decision theoretic framework, one can take account of this by assigning a higher amount of money to avert a terrorist risk than other risks - perhaps $50,000,000 per life rather than the $6,100000 per life now being used by US EPA and its equivalent in NRC.

    It is hard to quantify the importance of living in a free society with our human rights that are so important to us. We must beware of giving up these rights for too small a benefit. I do not believe I am alone in thinking that it is these rights as a free man that makes life worth living.    Much more important is a comparison with the narcotics industry. Although the deliberate destruction of life and property on 9/11 was an evil act, its consequences were far less than the yearly evil of drug traffic. Drugs kill or destroy many more people and are far more destructive of US society.  Drug addiction can create despair. Desperation is, I believe, one of the motives that drives people to terrorism. We also must not forget the drug which society has accepted and society is intermittently trying to eradicate - nicotine. 

    The New Yorker caught this idea well with Gregory's cartoon

“If you still want to belong to an organization dedicated to killing Americans, there’s always the tobacco lobby.” (One Taliban soldier to another.)

ID: 47397, Published in The New Yorker February 4, 2002

Available on
Cartoon bank ID 47397

Selected Related pages and Links

Richard Wilson's Home page
Presentation to first Sakharov Conference on Physics on a visit to the Armenian/Azeri border
Presentation to Conference on Self  Determination, Moscow, 1999
Letter to President Bush September 2001
Harvard/MIT Arsenic Project
Link to Andrei Sakharov Foundation
Link to Christian SolidarityWorld Wide
Link to Glasnost Foundation
Link to Amnesty International
Link to Gush Shalom