Extreme threats to life are those which could cause several hundred thousand to several million deaths. They are more troublesome and in the aggregate certainly more likely to occur than catastrophic threats. While such threats could cause major damage to the nation, they would not threaten its very existence. They include lesser versions of catastrophic threats, and fall into the same general categories: major natural upheavals, pandemics, and nuclear disasters. These are discussed in more detail below.

MAJOR NATURAL UPHEAVALS

Smaller Asteroids and Large Meteors

The Meteor Crater in Arizona was caused some 50,000 years ago by a large meteor which apparently broke apart before hitting Earth. The biggest fragment, only some 20 meters in diameter, struck with a force estimated at 2.5 megatons and created a crater 1.2 kilometers wide. This provides a good illustration of what could be expected from relatively small impacts.

Another illustration is a 1908 explosion over Tunguska, Siberia. This event has generally been attributed to a stone meteorite some 30 meters in diameter. The explosion has been estimated at 10-20 megatons. Because it was such a remote area, only one death was directly attributed to it, but it felled trees over more than 2000 square kilometers.

Overall, it would be difficult for a such an event to rise to an extreme magnitude. The land area of the United States occupies less than 4% or the Earth's surface. With population and resources concentrated in some 30 major metropolitan areas, the high-density portions of the nation make up far less than 1% of the Earth's surface. Small impacts outside these high-density areas would not have an extreme effect on the nation. Somewhat larger impacts anywhere on the globe, impacts not large enough to initiate a full scale Winter Night, but large enough to significantly degrade solar radiation reaching Earth's surface for an extended period, could partially collapse the food chain and result in millions of deaths globally. The United States, with its extensive resources, would be relatively well positioned to deal with such a crisis.

On the other hand, there are many times more small asteroids and large meteors than there are asteroids of a kilometer or larger in size. So such events are probably separated by thousands of years rather than millions. Also, there is a program to identify and track the larger asteroids, but we would probably be unaware of a smaller asteroid or large meteor until it actually hit. Although tracking all or most of these objects is now impractical, the combination of experience from tracking the larger asteroids and the continuing improvements in computers and tracking equipment means that such an effort may become feasible in the not too far distant future. For now, this is a threat that we simply must live with.

Vulcanism

As with asteroids, the most significant threat is from a volcanic event that would be large enough to initiate a Volcanic Night, significantly blocking sunlight for a year or more. Lesser events – the volcanic events that humanity has faced through history – pose mainly a localized threat.

Probably the largest volcanic explosion in recorded history was Krakatoa, an undersea volcano in the Sunda Strait in 1883. The combined effects of pyroclastic flows (turbulent clouds of hot gas and rock fragments), volcanic ashes and tsunamis had disastrous results in the region. There were no survivors from 3,000 people located at the island of Sebesi, about 13 km from Krakatoa. Pyroclastic flows killed around 1,000 people at Ketimbang, Sumatra, some 40 km north from Krakatoa. Although the region was a sparsely populated area, the official death toll in Sumatra reached over 35,000. More were probably killed by tsunamis throughout the region. The eruption produced a worldwide volcanic dust veil which acted as a solar radiation filter, reducing the amount of sunlight reaching the surface of the earth. In the year following the eruption, global temperatures were lowered by as much as 1.2 degrees Celsius on average. Weather patterns continued to be chaotic for years, and temperatures did not return to normal for five years.

There are few places in the United States where volcanic activity could reach this level of destructiveness. A relatively small explosion of the Yellowstone super volcano would certainly affect that area of the country, which remains rather sparsely populated. Another possibility would be in the Hawaiian islands, where undersea volcanic activity could conceivably mirror the Krakatoa event. The Krakatoa explosion was preceded by many smaller eruptions, so it did not come without warning. The largest explosive eruption on Hawaii within historical time occurred in 1790. This eruption produced pyroclastic surges that originated at Kilauea's summit and flowed several miles to the southwest. The thick deposits of ash exposed at many sites on the island indicate that even larger explosive eruptions occurred in prehistoric times and probably originated from Mauna Kea as well as from Kilauea. Explosive eruptions of any size take place infrequently in Hawaii. Since 1912, the Hawaiian Volcano Observatory has monitored volcanic activity on the islands for any signs of impending eruptions. The most widespread hazard from an explosive eruption would be windborne ash, which could damage structures, machinery, and agricultural crops. But an explosive eruption combined with seawater penetration could result in widespread casualties. Even in this extreme case, with Honolulu having a population of under 400,000 and the entire state of Hawaii only slightly over one million, casualties would be unlikely to exceed several hundred thousand.

Summary

Overall, there are no significant meteorite or volcanic threats which would reach into the extreme range of casualties.

PANDEMICS

A pandemic killing over a million Americans is well within the realm of possibility. The 1918 flu epidemic infected 28% of Americans and killed nearly 700,000 – a lethality rate of 2.5%. A similar outbreak today could certainly infect more than 28% of the country considering the much higher population density and widespread travel. But it has to be noted that many of the 1918 deaths were from secondary bacterial infections which can now be effectively treated. A death toll of several million could conceivably be reached.

Against this background, recent outbreaks of avian influenza have been very sobering. By 2007, it had infected only 256 people in 10 countries — mostly people in close contact with chickens in Asia — but the pathogen has had a staggering 59% lethality. Conditions also exist for the disease to become highly contagious. One possibility would be for the avian influenza virus to exchange genes with a common form of flu that routinely infects people. Should this happen, it could acquire the basic genetic blueprint for spreading quickly -- and explosively -- through human populations. Scientists believe a similar exchange of genetic material occurred prior to 1918.

Although avian influenza is the most prominent candidate for a new pandemic, it is not the only one. In November, 2002, a previously unrecognized disease appeared and became referred to as Severe Acute Respiratory Syndrome (SARS). By July 2003, there had been 8,096 known cases in 29 countries and 774 deaths (a mortality rate of 9.6%). By late 2003, the disease seemed to have run its course, thanks to close and proactive international cooperation. There was no vaccine or treatment; it responded to traditional treatment tools: isolation, infection control, and contact tracing. An epidemic does not seem likely, but development of effective drugs and vaccines will likely take considerable time. The virus has been characterized as sufficiently transmissible to be able to cause a large epidemic, but not so contagious as to be uncontrollable with good public health measures. Overall, SARS certainly remains a pressing concern; as with avian flu, viral mutations could result in an extreme global threat. There are also a number of African filoviruses (including Marburg fever and ebola) which have a potential for causing global disaster, particularly if viral mutations make them more transmissible.

Acquired Immune Deficiency Syndrome (AIDS) first came to the attention of medical authorities in June, 1981. Since then, the virus has infected some 65 million people and killed 25 million of them. Although drugs have made it treatable in many cases, it continues to take a heavy toll, especially in Africa. Mankind is fortunate that AIDS requires intimate contact for transmission. But AIDS is a stark reminder that new and highly virulent diseases can emerge unexpectedly. Another new disease, just as virulent but readily transmissible, could certainly wreak havoc with world health.

Overall, natural pandemics pose a significant threat of extreme damage to the nation. To address this threat, the nation has allocated over seven billion dollars, instituted a widespread surveillance program, initiated a crash development program of vaccine development, and begun stockpiling of anti-viral medicines. Unfortunately, since the flu virus mutates so rapidly, no one can be sure that these vaccines or medicines will be effective against an emerging viral outbreak. Nevertheless, it is expected that they would give some protection and reduce the effect of any pandemic. Although most of this effort is concentrated on addressing avian influenza, many of the actions would be applicable to any pandemic.

Bioterror

Although the threat of natural pandemics is distressing enough, such pandemics could be amplified or initiated by purposeful terrorist actions.

One geneticist recently startled the scientific world by creating the first live, fully artificial virus in the lab. It was a variation of the virus that causes polio, yet different from any virus known to nature. New techniques developed by other scientists could allow the creation of synthetic viruses in mere days, not weeks or months. Hardware unveiled last year by a Harvard genetics professor can churn out synthetic genes by the thousands, for a few pennies each. Along with synthetic biologists, a separate but equally ardent group is pursuing DNA shuffling, a kind of directed evolution that imbues microbes with new traits. Another faction seeks novel ways to deliver chemicals and medicines, using ultra-fine aerosols that penetrate deeply into the lungs or new forms of microencapsulated packaging that control how drugs are released in the body. Still another group is discovering ways to manipulate the essential biological circuitry of humans, using chemicals or engineered microbes to shut down defective genes or regulate the production of hormones controlling such functions as metabolism and mood.

An unclassified CIA study in 2003 titled "The Darker Bioweapons Future" warned of a potential for a "class of new, more virulent biological agents engineered to attack" specific targets. "The effects of some of these engineered biological agents could be worse than any disease known to man," the study said. One possible source could be a "lone wolf": a scientist or biological hacker working alone or with a small group, driven by ideology or perhaps personal demons. "All it would take for advanced bioweapons development," one specialist warned, "is one skilled scientist and modest equipment -- an activity we are unlikely to detect in advance."

So the explosive development of biotechnology not only expands our ability to address emerging threats, it also expands the potential for threats to emerge. It seems clear that in the years immediately ahead a designed pathogen could threaten the lives of millions of Americans, as well as many millions more globally. Nevertheless, surreptitiously developing truly virulent pathogen along with the means for widespread delivery would be a very difficult task.

Summary

Pandemics pose a significant threat to the nation; bioterror somewhat amplifies this threat. As for federal responses, the Department of Homeland Security is heavily focused on a terrorist threat, and the Federal Emergency Management Agency barely addresses the biological threat. It is the Department of Health and Human Services which carries almost the entire federal effort, responsible for both the Bioshield program and the national strategy addressing bird flu.

NUCLEAR DISASTERS

Nuclear incidents which could threaten millions of American lives fall into three general categories: individual weapon detonations, radiation dispersal incidents, and improvised nuclear devices.

Individual Weapon Detonations

While a comprehensive nuclear strike could destroy the nation, a single weapon detonation could destroy a major city, kill a million or more people, and make a huge mess, but it would basically leave the country intact. Such a strike could come from three sources: an intentional strike by a major power, a strike (perhaps covert) by a minor nuclear power, or an unauthorized strike launched by a rogue commander.

The only major powers capable of launching an intentional strike would be Russia or China. Russia, with its reliable, high-yield thermonuclear weapons, is a particular concern. Retaliation would surely follow, so such a strike would almost certainly be in some extreme situation. It might be theoretically possible, for example, for China to launch such a strike and then tell the United States that it is prepared to destroy the United States while absorbing whatever retaliation the United States could muster. But China is in no position now to even suggest such a risky gambit for it has only a minimal nuclear force. With Russia, we are still in a position of Mutually Assured Destruction, so it would make little sense for Russia to commit suicide by mounting a nuclear attack against the United States. Such scenarios lack even minimal rationality. But considering that actors are not always rational, the scope of forces in place, and the potential for very basic misunderstandings, such an exchange remains possible.

There are only a couple minor nuclear powers that could launch a strike against the United States with relatively low yield weapons. Iran may be developing both a warhead and an intercontinental missile, but at the moment has neither. North Korea apparently has a nuclear weapon, but the one test indicated at least a partial dud, and the last test of a longer range missile was also a failure. In the best of circumstances, such a strike could only hit Hawaii and possible Alaska or the US West Coast. North Korea could also launch a shorter range, ship-borne missile against Hawaiian or West Coast targets, or smuggle a weapon into a US port. Of course North Korea well knows that any such strike would result in swift retaliation and certainly lead to the fall of the regime. Nevertheless, if the regime felt it were failing anyhow, it could turn to some kind of final thrust against a long-term enemy. The other worrisome possibility is with Pakistan, at present an ally, but an unstable one. A takeover of all or part of the country by extremist elements remains possible. Suicidal elements could launch a strike on US assets regardless of consequences. A radicalized Pakistan would lack a missile capable of reaching the United States, but could certainly turn to alternative delivery means.

In the longer run, the United States could face a much wider range of nuclear armed states. North Korea's nuclear test and Iranian nuclear efforts have spurred a new interest in nuclear weapons. As many as 40 more countries have the technical skill, and in some cases the required material, to build a bomb – Taiwan, Brazil, Egypt, Saudi Arabia, South Korea and Japan are among countries which raise specific concerns. Strengthening the Nuclear Nonproliferation Treaty would seem to be an important objective, but recent actions have gone in the opposite direction, including US support for increased Indian nuclear programs and similar Chinese support for Pakistani programs.

An unauthorized launch could potentially be carried out by some rogue commander in the Russian or Chinese forces, as well as within our own forces or those of our French or British allies. In our own forces we have worked hard to put extensive safeguards in place to negate such a possibility, and we have doubtless shared some of this technology with our Allies and probably also with Russia. Nevertheless, no system is foolproof. The larger the size of existing forces, the larger the potential for some unauthorized actions.

Support for nuclear nonproliferation is languishing. The failure of the United States and Russia to continue reductions in their nuclear arsenals is not only in direct violation of Article VI of the treaty, it means that Russia maintains a troubling strike capability and it also sets a tone of disregard for the treaty itself. US nuclear support for India, although it can improve relations with this important nation, also undermines support for the treaty as does the continuing reluctance of the United States to ratify the Comprehensive Test Ban Treaty. One result is an increased likelihood that additional nations will seek nuclear weapons.

Nonmilitary actions to address threats of nuclear strikes have been mainly diplomatic efforts focused on the Iranian and North Koren programs. These are complex negotiations involving a number of countries with varying interests, and are also complicated by the fact that Iran insists that its intentions only involve peaceful use of nuclear energy, while North Korea has already detonated a test device. Specific issues change almost daily, but in the end agreement will hopefully be reached with both nations on agreements which will limit their nuclear weapon potentials. Unfortunately, this is far from certain and US efforts to structure sanctions and international pressure on both nations has been met with considerable skepticism by the other nations involved.

Military actions fall into two basic groups: potential US strikes against Iranian or North Korean targets and active programs of anti-missile defense to blunt not only these threats but also threats of individual missile launches from other quarters. Military strikes on either Iran or North Korea are highly problematical, not only because of their uncertain effectiveness, but also because of their potential impact on neighboring countries and international relations. Both nations have gone to considerable effort to conceal program elements and to place them in protected locations, particularly underground, so it is unclear what air or missile strikes could even accomplish.

US anti-missile programs have been ongoing for a number of years. They are specifically intended not to be comprehensive protective systems, but rather systems capable of thwarting strikes by one or a few ballistic missiles. Unfortunately, the systems have not performed well in tests, shorter-range theater anti-missile weapons have performed very poorly in combat; the systems are vulnerable to a range of countermeasures, and they offer no protection against shorter-range sea-launched missiles or smuggled weapons. Although the system capabilities remain problematical, the costs have been substantial. Additionally, future developments are tied with space weapon developments.

Radiation Dispersal Incidents

Chernobyl provided another illustration of how no system is foolproof. The reactor crew took advantage of a shutdown for routine maintenance to perform some emergency reaction tests. Violating a number of safety procedures, they pushed the reactor into a very unstable situation. Then a sudden temperature surge led to a catastrophic steam explosion that resulted in a fire, a series of additional explosions, and a nuclear meltdown. Large areas of Ukraine, Belarus, and Russia were badly contaminated, resulting in the evacuation and resettlement of over 300,000 people. There were 56 direct deaths from the accident and estimates that as many as 9,000 others might eventually die from some form of cancer induced by the accident, though actual deaths appear to have been less than anticipated.

The other significant reactor accident was at Three Mile Island. In this instance, the main feedwater pumps stopped running, caused by either a mechanical or electrical failure, which prevented the steam generators from removing heat. Then a pressure-relief valve failed, unknown to the operators, and eventually caused a loss-of-coolant accident resulting in the meltdown of the reactor core. But there was no breach of the containment walls, no significant release of radiation, and no fatalities.

The experience with these two accidents indicates that reactor accidents and radioactive dispersal incidents are unlikely to rise to high levels of deaths. While economic consequences may be significant, including a need for widespread and semi-permanent evacuations, the overall impact on the nation would be modest. This is particularly so since most nuclear reactors are not close to population centers.

Terrorist groups have also considered causing a radiation dispersal incident, including the potential for crashing an airplane into a reactor or employing a Radioactive Dispersal Device (“dirty bomb”). The Nuclear Regulatory commission has assessed that existing reactors are sufficiently robust that projected attack scenarios would be unlikely to result in widespread damage, and that the potential for disruption from a Radioactive Dispersal Device is modest, particularly because terrorist organizations would be unlikely to have access to significant amounts of highly radioactive substances.

Overall, it seems very unlikely that the results of a reactor incident (either accidental or intentional) or a Radioactive Dispersal Device would rise to the level of extreme damage, certainly not in terms of direct fatalities. On the other hand we can hardly insure that terrorists will be unable to get possession of a sufficient amount of highly radioactive material, and dispersing such material in a major downtown area would clearly have severe economic impact. A major protection is extensive intelligence networks which can identify and thwart potential smuggling attempts.

Improvised Nuclear Devices

Constructing nuclear weapons remains a very sophisticated process and will probably stay well beyond the capabilities of any subnational group. Nuclear weapons need to be in a relatively small, self-contained and deliverable package. They need to make efficient use of nuclear materials and be robust enough to sit in an arsenal for a number of years. They must above all be reliable, exploding with a design yield when a detonation signal reaches the warhead. Improvised nuclear devices do not have to meet any of these requirements. They could be large and unwieldy, perhaps built inside a 40 foot shipping container or a large truck, or assembled in the basement of a commercial building or a warehouse.

Even a relatively small explosion of 10 kilotons in a major city would be expected to kill 1-300,000 people, destroying everything within a half-mile radius and causing severe damage for miles beyond. In the end, years of cleanup of 3,000 to 5,000 square miles could be needed and some areas would probably have to be permanently closed.

Terrorist groups have been actively seeking nuclear capabilities, though they face many hurdles. Because of known ties between al Queda and a black-market nuclear network run by Pakistanis, it has to be assumed that terrorists have the know how to construct a crude improvised nuclear device. The biggest challenge they face is obtaining the necessary nuclear materials: highly enriched uranium or plutonium. Here, the largest concerns focus on Russia and Pakistan.

Russia poses large concerns because of the size and dispersion of its nuclear weapons complex. Security is often inadequate; at the same time, the rise of criminal organizations and the relative poverty of many workers in the nuclear complex make for a worrisome combination. Recognizing the dangers of loosely controlled nuclear materials, the United States initiated the Nunn-Lugar Cooperative Threat Reduction Program in 1991 -- a systematic effort to improve physical security and material accountability at scattered Russian nuclear facilities. This initiative resulted in a wide range of cooperative programs between the United States and the nuclear successor states of the Soviet Union. A bipartisan Task Force was convened in 2000 to assess program status and recommend further actions. The Task Force found significant improvements as well as continuing shortfalls and recommended a $30 billion program over ten years to address these. These programs continue to move forward.

These efforts have led, moreover, to broad multilateral programs. First the G8 launched a Global Nonproliferation Partnership in 2002, a $20 billion program with four primary goals: increasing security of nuclear and radiological materials, securing alternative employment for former weapons scientists, disposing of chemical weapons and dismantling nuclear powered-submarines. By mid-2006, some $17.5 billion had been pledged and $3.5 billion spent by 21 nations and the European Union. Building on this initiative, the United States and Russia, at the 2006 Group of Eight summit in St. Petersburg, proposed The Global Initiative to Combat Nuclear Terrorism to address the continuing security issues. These initiatives resulted in a substantial increase in efforts at improving the security of nuclear materials.

Pakistan poses an entirely different set of problems. It possesses nuclear weapons and has an unstable government (President Zadari has already faced several major challenges). Widespread sympathy for Muslim extremists raises the potential for insider cooperation with a terrorist organization as well as the potential for cooperation of individual nuclear technicians or scientists. Although the Pakistani nuclear complex is much smaller than the Russian one, there is no international program to help insure security of materials and weapons, nor is much known about the actual security measures in place. The prior extensive nuclear black market conducted by Pakistan's senior nuclear scientist, A.Q. Khan, also calls into question the degree of government control over the complex.

Relations with the United States are very complicated because of Pakistan's inability to control its border area, providing refuge and operational bases for insurgents fighting NATO forces in Afghanistan. These relations have been further strained by the US support for Indian nuclear programs discussed above. One positive element was extensive US aid to Pakistan following a devastating earthquake in October 2005. A US humanitarian operation began within 48 hours of the earthquake -- some 1,200 US military personnel and a fleet of 24 helicopters delivered over 15,000 tons of humanitarian aid in what has been called the largest disaster relief operation in US military history. Unfortunately, once the immediate crisis was over, US assistance simply ended. Since then little has been done to build good will within the country, despite the obvious opportunities to assist in areas such as infrastructure and education.

Although Russia and Pakistan pose the most urgent concerns, dozens of countries (including North Korea and Iran) pose some potential for leakage of key nuclear materials, highly enriched uranium (HEU) or plutonium. Thankfully, production of either of these materials requires substantial industrial capability, something that terrorist groups would be unlikely to acquire or to be able to operate surreptitiously.

Having HEU would greatly simplify the task for terrorists as it can relatively easily be fashioned into an improvised nuclear device. Because of the higher radiation flux from plutonium (especially from reactor grade plutonium), its use in weapons requires a high degree of sophistication. It would also be difficult to construct an improvised nuclear device with plutonium. Such a device would be much more likely to produce a fizzle of a result, something that would be a gross failure for a weaponeer. But for a terrorist, even an explosion equivalent to only several tons of TNT would be a great success. An explosion of this magnitude is still large by conventional standards. It would not destroy a city, but it would certainly destroy a number of buildings. It would vaporize essentially all of the plutonium and would create a huge contamination problem in an urban area, not to mention potential fires. And the very fact that terrorists had actually caused a nuclear explosion would spread panic at the scene and would greatly heighten security concerns ever after.

We have to assume that terrorists have sufficient knowledge to build some improvised nuclear device. And it is likely that they could get the cooperation if not the dedicated support of knowledgeable Pakistani nuclear technicians and maybe even weapon scientists. Knowledge is not the barrier, rather getting sufficient HEU or plutonium is the barrier. Preventing this has been the focus of efforts to thwart terrorist efforts to acquire nuclear capabilities.

Preventing delivery of an improvised nuclear device would be much more difficult. Both uranium and plutonium emit alpha radiation, which can be effectively shielded even by a sheet of paper. However, some of the radiation decay products do emit more penetrating radiation, so shielding a device from radiation detectors is somewhat more difficult. Nevertheless, a detector would have to be extremely sensitive to detect a smuggled device, or smuggled materials for use in a locally constructed device.

Overall, the potential for an eventual terrorist use of an improvised nuclear device remains significant.

Summary

President Bush had characterized the use of Weapons of Mass Destruction by radicals as the gravest danger the nation faces. Actually, because of the high-yield weapons available, a Russian nuclear threat does pose a threat of larger magnitude, though probably lower probability. Little has been done in recent years to address the challenge of the needlessly large nuclear arsenals held by both Russia and the United States.

Other nuclear powers (including North Korea and potentially Iran) pose threats of lesser magnitude, particularly since these nations lack a reliable means of delivery against targets in the United States. Efforts to address these threats have fallen into several general categories:

- Diplomatic efforts, which have had uncertain results and have mostly ignored the threat of an unstable, nuclear-armed Pakistan. These efforts also face a basic nonproliferation dilemma: sovereign states inherently have as much right to develop nuclear weapons as the United States had. The Nuclear Nonproliferation Treaty also gives signatories an absolute right to withdraw from its obligations (as North Korea has done). So international efforts to restrain a spread of nuclear weapons must stress incentives and sanctions, neither of which provide any real barrier.

- Export controls on materials and equipment necessary for a weapons program have made it quite difficult for non-nuclear states to maintain an active weapons program. In Iraq's case, a combination of controls and sanctions had effectively forced Saddam Hussein to eliminate his program; they also led Libya to eliminate a weapons program. But North Korea clearly shows that the controls cannot stop a determined state.

- Military strikes were effective against Iraq's program, destroying its last vestiges as well as Saddam Husein's control over the country. Military options are less attractive against North Korea and Iran for a variety of reasons. Military defensive measures, particularly anti-missile systems, only address one aspect of the nuclear threat. This option could be attractive if it provided a reliably effective system at a moderate cost. Unfortunately present systems provide neither.

- Intelligence efforts to identify weapon activities and locations in potentially hostile states. But these systems functioned poorly during the crisis leading up to the Iraqi War and seem to be only marginally effective in the Iranian and North Korean cases.

The main impact of a radiation dispersal incident would be economic and would be contained fairly rapidly, as was the case with Chernobyl. This would be particularly true for a reactor incident. A radiation dispersal incident within a major city could be much more damaging, but would require a quantity of radioactive material which radical groups would have difficulty obtaining. The high levels of radiation emitted by such materials would also complicate an effort to smuggle it into the country if obtained abroad.

Improvised nuclear devices remain a major concern. They could inflict severe casualties, as well as have a severe economic impact. Because of their low radiation signature, it is very difficult to block the smuggling of required nuclear materials into the country. The use of radiation detection devices, although reassuring, is essentially useless against this challenge. So efforts to enhance the security and control of such materials remains the most important means of countering this threat. Second to this is probably intelligence efforts to identify radical elements and monitor their activities.

SUMMARY

Overall, there are a number of extreme threats to the nation. The most significant ones are a pandemic (either natural or incited), a nuclear strike (especially involving a high-yield Russian weapon or a Pakistani or North Korean weapon stealthily delivered), or an improvised nuclear device detonated inside a major city. Planning to deal with the aftermath of any of these events is a daunting task facing in the first instance for the Department of Homeland Security (including the Federal Emergency Management Agency).

Federal efforts to address threats have been inadequate and unbalanced. Budget figures can give some appreciation of this imbalance but cannot provide definitive and quantitative comparisons because so many programs have multiple inputs and also multiple objectives.

Improving the response capabilities of the Department of Homeland Defense is certainly a priority item, particularly since many of these capabilities would be useful in any disaster situation. But resources in this area have been modest and many of these funds have been poorly spent. The department was widely criticized, for example, on its distribution of funds intended to improve local response capabilities. More recently, a major program to upgrade Coast Guard capabilities has ground to a halt because of poorly designed and constructed patrol ships.

Improvements in public health capabilities not only improve responsiveness to a potential pandemic, but to any public health emergency. Indeed, improved capabilities also support ongoing public health maintenance. Nevertheless, total expenditures focused on pandemic threats on the order of $1 billion/year.

Funding for the Cooperative Threat Reduction programs with Russia is roughly at this same level, even though it directly addresses a critical element of the nuclear threat – the potential for radical elements to obtain fissile nuclear materials. By broadening US-Russian relations, it also helps to ease the threat of a Russian missile strike. But arms reduction efforts which could directly address this threat and also support nuclear nonproliferation efforts receive minimal funding or attention, as do efforts to reduce the potential for leakage of Pakistani weapons or materials.

On the other hand, anti-missile programs which marginally and ineffectively address only one narrow aspect of the nuclear threat are funded at some higher levels. Similarly, programs to detect nuclear materials inside incoming shipping containers have a high projected funding, even through it would be difficult to detect shielded material and this is a relatively unattractive smuggling route. Furthermore, many of these systems would only detect materials being unloaded at port, so can not address the threat of a nuclear device inside a container being detonated in port before unloading.

Military force levels, which provide a direct strike capability against adversarial nations, are structured to address a broad range of challenges to national security. A significant percentage of the annual military budget is now being consumed by actions in Iraq and Afghanistan, but an even larger proportion supports the whole spectrum of national military capabilities. Little, if any, of this is specifically intended for actions against adversarial states or terrorists, but it gives the nation a broad range of options in dealing with them.

While intelligence directed against adversarial nations such as Iran and North Korea seems to have been only marginally effective in addressing the challenges these nations pose, it has been much more effective in tracking and neutralizing terrorist threats. Many of the threats have been by unprofessional amateurs. The London and Madrid bombings serve as reminders that small groups acting with professional demeanor are very difficult to identify and can wreak havoc. But an incident involving an improvised nuclear device would necessarily involve a relatively large international effort. A comprehensive intelligence network with broad international ties makes such an operation very difficult. So while the effectiveness of intelligence assets is very difficult to evaluate, their presence significantly improves our national ability to address these threats.

Overall, pandemics, a strike by a minor nuclear power, and improvised nuclear devices are the only extreme threats which seem to rise above a negligible level of probability. Addressing them requires augmented response and broad intelligence capabilities.