The New York Review of Books
Volume 55, Number 3 · March 6, 2008
The Greatest Threat to Us All
By Joseph Cirincione
Arsenals of Folly: The Making of the Nuclear Arms Race
by Richard Rhodes
Knopf, 386 pp., $28.95
The Seventh Decade: The New Shape of Nuclear Danger
by Jonathan Schell
Metropolitan, 251 pp., $24.00
Deception: Pakistan, the United States, and the Secret Trade in Nuclear Weapons
by Adrian Levy and Catherine Scott-Clark
Walker, 586 pp., $28.95
America and the Islamic Bomb:The Deadly Compromise
by David Armstrong and Joseph Trento
Steerforth, 292 pp., $24.95
Charles Gibson of ABC News began the New Hampshire debate among the Democratic presidential candidates with a question on nuclear terrorism. Though not discussed in any detail in the campaign, he said, it remains "the greatest threat to the United States today." He was right and, as some of the candidates noted, the threat has grown worse during the Bush administration as terrorist groups have thrived while efforts to lock up vulnerable nuclear materials have languished. The resulting discussion confirmed both the collapse of Bush's security strategy and the need for clear conceptions to replace it.
Announced in Bush's "axis of evil" speech, his 2002 State of the Union address, the Bush Doctrine held that the main danger to the United States came from the nexus of hostile regimes, terrorist groups, and nuclear weapons. One solution was preventive war. The Iraq invasion was the first attempt to carry out this radical strategy, but it was intended to be just the start of a series of regime changes in the Middle East, with Syria and Iran to follow.
The disastrous conflict in Iraq has long since shown how misguided the Bush Doctrine was; recently its deeper flaws have been exposed by the new National Intelligence Estimate (NIE) on Iran and by such events as the assassination of Benazir Bhutto and the intensification of the crisis in Pakistan. The new NIE—representing the unanimous opinion of all sixteen US intelligence agencies—concluded that Iran had ended its work on building a nuclear weapon in 2003. "Tehran's decision to halt its nuclear weapons program suggests it is less determined to develop nuclear weapons than we have been judging since 2005," the agencies said. "We do not know whether [Iran] currently intends to develop nuclear weapons."
But the report's conclusions about the Iranian regime were perhaps the most telling. "Tehran's decisions," according to the NIE, "are guided by a cost-benefit approach rather than a rush to a weapon irrespective of the political, economic, and military costs." The estimate pointed the way to a new US policy toward Iran that many, including this writer, have been urging:
Some combination of threats of intensified international scrutiny and pressures, along with opportunities for Iran to achieve its security, prestige, and goals for regional influence in other ways, might—if perceived by Iran's leaders as credible—prompt Tehran to extend the current halt to its nuclear weapons program.
At least for a while, the estimate undermined talk of military intervention in Iran.
The violence in Pakistan, meanwhile, has shown the extent of the failure of the Bush Doctrine by bringing the real, imminent security threats to the United States into stark relief. Osama bin Laden is widely thought to be hiding in Pakistan, a country with a substantial nuclear arsenal, strong Islamic fundamentalist influences in its military and intelligence services, and a military dictatorship seemingly in danger of collapse. In addition, the United States now faces: (1) a nuclear-armed North Korea; (2) the possibility of a Middle East with several nuclear states, Egypt, Turkey, and Saudi Arabia among them; (3) the increasing danger of weapons from other countries falling into the hands of terrorist groups, while American-led programs to secure nuclear bomb materials around the world are being neglected; (4) an upsurge in the pursuit of civilian nuclear power by many countries that could put them within reach of nuclear weapons capacity; and (5) the possibility that flaws in US and other command and control systems—including those exposed last August by the unauthorized flight from North Dakota to Louisiana of a B-52 bomber armed with six nuclear bombs —could result in the accidental or unauthorized use of nuclear weapons.
To understand the roots of this strategic failure, we have no more reliable guide than Richard Rhodes, author of The Making of the Atomic Bomb (1986), which won the Pulitzer Prize, and Dark Sun: The Making of the Hydrogen Bomb (1995). His excellent new book is entitled Arsenals of Folly: The Making of the Nuclear Arms Race. The three together tell us much about how the US went from the atomic discoveries of the 1930s to the irrational situation in the 1980s in which a total of 65,000 nuclear weapons were held by the United States and the Soviet Union. Although the global arsenals have since been reduced to some 26,000 bombs, the United States and Russia continue to possess most of the world's nuclear warheads, with the other seven nuclear nations together holding the remaining one thousand.
Arsenals of Folly examines the cold war arms race not by recounting treaty negotiations but by studying the psychology, physics, and politics of the era. Perhaps Rhodes's most valuable contribution is his meticulous documentation of how American officials frequently and deliberately inflated their estimates of military threats facing the United States, beginning with the 1950 report to President Truman, known as NSC-68, that exaggerated Soviet military capabilities. As we know from misleading assessments about Iraq and now Iran, threat inflation has continued to this day.
America faces real threats that need no embellishment. But as Rhodes shows, politicians have often exaggerated threats for political advantage. "Fear is a very dangerous thing," said British Prime Minister Stanley Baldwin after World War I. "It is quite true that it may act as a deterrent in people's minds against war, but it is much more likely to act to make them want to increase armaments...."
The manipulation of fear to promote programs that Americans would otherwise not support is different from honest disagreement over the scale of the threats. Rhodes shows how Paul Nitze, the principal author of the 1950 NSC report, intentionally exaggerated Soviet nuclear capacities and minimized those of the US in order to "bludgeon the mass mind of 'government'"—as Nitze's superior, Secretary of State Dean Acheson, admitted years later. Although the Soviet Union had lost at least 25 million people and half its industry in World War II, Nitze portrayed the USSR as a fanatical enemy that, within a few years, would threaten America with an estimated two hundred nuclear weapons. According to his report, the then American stockpile of 1,400 weapons would be insufficient to counter such a threat. Nitze's report came at a time when international events, including the Korean War, seemed to validate this dark vision. In response, Truman quadrupled the defense budget and began a strategic program that would increase the US nuclear arsenal to some 20,000 thermonuclear bombs by 1960 and 32,000 by 1966.
The threats were real, but the aggressive American buildup created new dangers without diminishing the Soviet problem. When Richard Nixon began his policy of détente with the Soviets to reverse these trends, Nitze formed, with Albert Wohlsetter at the University of Chicago, the Committee to Maintain a Prudent Defense Pol-icy. It was the first of several private organizations that recruited young graduate students, including Paul Wolf-owitz and Richard Perle, with the explicit aim of subverting any plans to reduce the nuclear arsenal. "In doing so," Rhodes writes, Nitze "unleashed a team of sorcerer's apprentices whose trail of wreckage extends well into the present century."
In 1976 George H.W. Bush, then the director of the CIA, set up a "Team B" of private analysts hand-picked by Nitze's group with the blessing of Dick Cheney, then President Gerald Ford's chief of staff, and Donald Rumsfeld, then secretary of defense. Professor Richard Pipes of Harvard directed the team, which in December of that year produced a wildly exaggerated portrait of a Soviet empire bent on world domination.
Although the newly elected president Jimmy Carter rejected the report and disbanded the group, Team B continued its activities by forming a new Committee on the Present Danger whose members included Norman Podhoretz, Edward Teller, William Casey, and Jeane Kirkpatrick. The committee popularized the notion that the United States had a "window of vulnerability" in its nuclear arsenal because, they claimed, the Soviet Union could eliminate in a first strike all of America's nuclear weapons. In fact it would have been impossible for the Soviets to do so, since nuclear submarines and aircraft equipped with weapons would have escaped any land attack; the submarines were invulnerable and their ability to launch a counterattack would have maintained an effective deterrent if the Soviets were foolish enough to consider a first strike.
The historian Anne Cahn has shown that every specific claim about the Soviet arsenal in the Team B report was wrong, including the assertion that there was a super-secret Soviet facility that was developing a nuclear-powered laser beam (later shown to be a rocket engine test site). Nonetheless the claims of Team B contributed to the image of Carter as a weak president unwilling to stand up to Soviet threats; this helped secure Reagan's victory in the 1980 election and the arms buildup that followed.
Subsequent groups have copied the Team B strategy. In 1998, the Republican-controlled Congress established the Commission to Assess the Ballistic Missile Threat to the United States, led by Donald Rumsfeld. By consistently applying worst-case assumptions, the Rumsfeld Commission warned that Iran and North Korea could hit the United States with missiles within five years. The assessment was simply wrong. North Korea does not have, and is unlikely to have anytime soon, a nuclear missile that can hit the United States; Iran is even further away from such a capacity. Indeed, the overall threat from ballistic missiles has declined, with fewer nations and fewer missiles threatening the United States today. The report, however, was successful in persuading Congress to boost spending on antimissile systems from $3 billion annually to $11 billion in 2007.
In 2000, the Rumsfeld Commission on space weapons again used a series of worst-case assumptions to conclude that the country faced an imminent "space Pearl Harbor." That report led to the current US strategy to deploy new weapons—such as orbiting interceptors to target other nations' satellites and missiles—for total US domination of outer space. In fact, no nation credibly threatens the vast US satellite system.
Under President George W. Bush, the practice of exaggerating threats to the United States in order to justify aggressive military policies has been taken to alarming extremes. The Bush administration came into office in 2001 openly scornful of the nuclear policies of its predecessors, Republican and Democratic. The problem, it said, was not controlling and eliminating existing stockpiles of nuclear weapons but dealing with the evil regimes that are trying to acquire them. The answer was not negotiated agreements but the forceful overthrow of those regimes. Rumsfeld and his aides put forward a National Intelligence Estimate on Iraq in 2002 that made bald claims about Saddam Hussein's nuclear, biological, and chemical weapons programs and helped stampede the nation to war.
As with Team B, the report was wrong in every single assertion. Saddam Hussein had abandoned his nuclear and chemical weapons programs in 1991 and his biological weapons program in 1994. The leader of the Iraq Survey Group, David Kay, concluded in January 2004 that the regime had been in a "death spiral," growing weaker, not stronger. For the US, the result of this rush to invade Iraq has been one of the most devastating declines in security, power, and prestige in American history.
The exaggeration of foreign threats, however pernicious, is a tactic. The arms buildup it serves is the greater folly. "Threat inflation," Rhodes writes,
was crucial to maintaining the defense budgets of the Cold War.... Fear was part of the program, the psychological response to threat inflation that delivered reliable votes.
The cold war arms race was not, he argues, a natural condition of the US–Soviet rivalry. Those who claimed to act out of patriotism perpetuated the waste of billions of US tax dollars, squandered the possibility of achieving lasting nuclear security, and weakened America's global standing.
The $5.5 trillion spent on nuclear weapons—"enough to buy everything in the United States except for the land," noted Carl Sagan—was money not invested in domestic needs. Rhodes writes:
Far from victory in the Cold War, the superpower nuclear-arms race and the corresponding militarization of the American economy gave us ramshackle cities, broken bridges, failing schools, entrenched poverty, impeded life expectancy, and a menacing and secretive national-security state.
Rhodes is fully aware of the brutality of Soviet rule, even under Gorbachev, but he skillfully draws on now available Russian records to show that the fundamental change Gorbachev offered was genuine. Perle, Wolfowitz, Cheney, and former secretary of defense Caspar Weinberger were, he shows, wrong to dismiss Gorbachev's repeated disarmament proposals as tricks. Those who dismissed Reagan's own repeated statements on the need for disarmament were also wrong.
In his famous 1983 "Star Wars" speech, Reagan said his proposed anti-missile system would open the way for the eventual elimination of the weapons themselves. The system itself was, Rhodes says, "a dream, a fantasy, an uninformed winner-take-all bet that American technology could make miracles happen." But Rhodes's account of the Reykjavik summit in October 1986—the fullest history yet of the meeting—shows how close Reagan and Gorbachev came to eliminating all nuclear weapons within ten years. Transcripts of their intense, lengthy talks show that both knew in detail the burdens of the arms race. The agreement foundered on Gorbachev's insistence on limiting the Star Wars program to basic research during those ten years and Reagan's refusal to do so.
Secretary of State George Shultz emerges from Rhodes's book as a hero for his support of Reagan's vision at Reykjavik. Shultz writes of those Reagan administration officials who opposed the president on disarmament, "The naysayers were hard at work." He continues,
No one could accept the thought of a world moving toward the elimination of nuclear weapons. Richard Perle declared...that the president's dream of a world without nuclear weapons—which Gorbachev had picked up—was a disaster, a total delusion. Perle said the [National Security Council] should not meet on the idea, because then the president would direct his arms controllers to come up with a program to achieve that result. The Joint Chiefs' representatives agreed with Perle. They feared the institutionalization and acceptance of the idea as our policy.
The summit failed but Reagan, Gorbachev, and Shultz persisted, negotiating the agreements—Start I and the INF Treaty—that, though short of abolition, eliminated thousands of missiles from Europe and cut the strategic arsenals of the two superpowers in half.
Jonathan Schell's The Seventh Decade: The New Shape of Nuclear Danger picks up where Rhodes leaves off, examining the essential question: What are nuclear weapons for? Invented to counter Germany, dropped on Japan, deployed against the Soviet Union, nuclear weapons, Schell writes, lost any conceivable rational purpose after the end of the cold war. What nation, what threat now justifies thousands of them? Or any? After the cold war, Schell writes,
The number of nuclear weapons continued to drop, but the essential features of the mutual annihilation machine remained intact. The question of why the former Cold War rivals wanted nuclear weapons was forgotten, and their arsenals drifted into a kind of policy-free zone. Unsustained by Cold War rationales but not yet assigned any new ones, they seemed to exist for their own sakes, leaving a strong feeling that in the new era, missions would be sought for nuclear weapons rather than the other way around.
Why is this dangerous system persisting? Schell believes that the policies of the current administration are largely to blame:
The distance of Bush's policies from previous American non-proliferation policy is hard to overstate. Every previous American president in the nuclear age had relied on peaceful means to stop proliferation.... Preventive war had on occasion been proposed by presidential advisers but was always rejected.... President Bush's demotion of diplomacy and treaties across the board was as clear as his elevation of force. In decision after decision, his administration tore at the web of arms control treaties that had grown up over four decades.
Schell argues convincingly that plans by the Bush administration for new nuclear weapons and for new uses for these weapons—such as bunker-busting deep penetration bombs— swung nuclear policy sharply away from deterrence and in the direction of nuclear use. "The mission of nuclear weapons is no longer to produce stalemate with a peer," Schell writes; "it is to fight and win wars against nations with little or no ability to respond." As if to demonstrate Schell's point, four of the Republican presidential candidates discussed using nuclear weapons against Iran in a CNN debate on June 5, 2007.
No more direct demonstration of the failure of US nonproliferation policy can be found than in Pakistan. Even before the Bhutto assassination, jihadists had stepped up their attacks on Pakistani military facilities. Ominously, these included several bases that house nuclear-related facilities, though it does not appear that these were the specific focus of the attacks. On November 1, a suicide bomber killed eight members of the Pakistani air force and wounded forty others at Sargodha Air Force Base in the Punjab that is the home of Pakistan's Air Force Central Command and the military headquarters for control of its nuclear arsenal. On December 10, another suicide bomber attacked a bus filled with thirty-five children of Pakistani air force officers at the Kamra Air Force Base in Peshawar province that includes facilities likely used for the storage and maintenance of Pakistani nuclear weapons.
Two new books provide essential information for understanding the nuclear dangers posed by Pakistan. America and the Islamic Bomb: The Deadly Compromise by David Armstrong and Joseph Trento and Deception: Pakistan, the United States, and the Secret Trade in Nuclear Weapons by Adrian Levy and Catherine Scott-Clark provide a disturbing picture of the proliferation network set up by Pakistani scientist A.Q. Khan, who presided over sales of nuclear materials to Libya, Iran, and other countries. Despite claims from Washington and Islamabad that his operations have been shut down, both books argue that the Khan network still exists, and both agree that Pakistan's nuclear weapons are not safe. Levy and Scott-Clark conclude:
Pakistan continues to sell nuclear weapons technology (to clients known and unknown) even as Musharraf denies it—which means either that the sales are being carried out with Musharraf's secret blessing, or that he did not know and is in no more control of his country's nuclear program than he is of the bands of jihadis in the tribal belt and Pakistan-administered Kashmir, which have merged with al-Qaeda.
The blame for Pakistan's potentially catastrophic nuclear situation lies far beyond the Bush administration. "US officials, and anyone else paying attention, knew for decades that Pakistan was trafficking in nuclear technology," Armstrong and Trento write.
Yet successive US administrations looked the other way as their sometime-ally first developed and then sold the building blocks for the ultimate weapons of mass destruction.
Of the more than fifty people identified as key figures in the Khan network, only a handful are in custody or face charges, and private companies Khan and others used to produce materials for nuclear weapons in Asia, Africa, and Europe continue to operate. The authors argue that "there is evidence that Pakistan's nuclear smuggling continues," at least to import materials for Pakistan's own use. In 2004, shipments of aluminum tubes from Russia destined for Pakistan were intercepted in Dubai, even though the network had been allegedly shut down. Pakistan has put few export controls in place; nor have any sanctions been levied in response to Pakistan's deceptions, even as the government continues to deny both the United States and the International Atomic Energy Agency access to Khan or his associates. Levy and Scott-Clark also cite a 2006 German intelligence service report that Pakistan was "still secretly buying and just as stealthily selling nuclear weapons technology." One of the German report's authors concluded, "They were buying to sell and it could no longer be hived off as rogue scientists doing the deed."
The current turmoil in Pakistan intensifies the gravest threat to American national security: that al-Qaeda could steal or acquire a nuclear weapon or the material to make one. Pakistan is now the most urgent risk, but not the only one. Fifty countries have stockpiles of materials that could be used for nuclear weapons. The supplies of uranium pose the greatest threat. With technical expertise supplied, for example, by former Russian or Pakistani nuclear scientists, terrorists would need only twenty-five to fifty kilograms of highly enriched uranium to fashion a "gun-assembly" bomb similar to the one dropped on Hiroshima. With half of the uranium at one end of a six-foot-long tube and half in a "bullet" propelled by conventional explosives from the other end, terrorists could create and carry in the trunk of a car a thousand-pound bomb that, if detonated in Times Square, could kill one million New Yorkers.
The key to stopping al-Qaeda or a similar organization from detonating such a device is not more border security (a bomb detonated in New York harbor would be almost as deadly) but preventing the group from getting highly enriched uranium and other bomb-making technology in the first place. In principle we know how to do this. Thousands of US and foreign civil servants are working, through government programs, to eliminate or secure supplies of bomb materials, particularly highly enriched uranium. The US has already done so with about half the material in Russia and has also removed materials from vulnerable sites in Kazakhstan, Serbia, the Czech Republic, and a half dozen other countries. This is why Graham Allison, an expert at Harvard on nuclear proliferation, calls nuclear terrorism "the ultimate preventable catastrophe." But we need to triple the budgets of these programs from today's $1 billion a year (or what we spend every two and a half days in Iraq). More important, we need a president who makes it a top priority to secure all nuclear materials and weapons around the world.
What are our chances of getting such a president? On the Republican side, Mitt Romney, before he suspended his campaign, had the most to say, perhaps reflecting the influence of his adviser, Mitchell Reiss, a respected proliferation expert and Colin Powell's former director of policy planning at the State Department. Romney said last April that he would appoint a senior ambassador to lead efforts to prevent nuclear terrorism, including accelerating and expanding efforts to secure global nuclear stockpiles. In addition, he would create an international bank of nuclear fuel to back up commercial supplies and would also make nuclear trafficking a crime against humanity on a par with genocide and war crimes.
John McCain devoted just one paragraph to proliferation in a Foreign Affairs article late last year, focusing on stricter export controls, harsher punishments for proliferators, and increased budgets for nuclear inspections. Mike Huckabee narrows the issue even further to a few sentences on the threat from Iran in his speeches. All want to deploy more anti-missile systems; none sees that preventing proliferation should be connected with reducing existing global arsenals. Romney and Huckabee reject any reductions and McCain is noncommittal.
The Democratic side has the greatest potential for transforming nuclear policy. Barack Obama has promised to lead a global campaign not just to reduce but to eliminate nuclear weapons. Obama has the most developed plan in the campaigns, based in part on work he has done with Senator Richard Lugar of Indiana and a bill he has introduced with Senator Chuck Hagel of Nebraska. In an October 2007 speech he endorsed a comprehensive plan to control and eliminate nuclear weapons around the world. According to the plan, the US would (1) secure during his first term as president all nuclear materials in the fifty countries that have them; (2) negotiate radical reductions in US and Russian nuclear stockpiles; (3) negotiate a verifiable global ban on the production of fissile materials; (4) create an international nuclear fuel bank; (5) increase funding for the inspections and safeguards done by the IAEA; (6) seek a global ban on all intermediate-range missiles; and (7) lower the current alerts that keep thousands of nuclear warheads ready to launch within fifteen minutes, thus reducing the risk that the weapons would be used by accident or misperception.
Hillary Clinton has promised similar presidential attention to preventing nuclear terror and shrinking global arsenals. In an article in Foreign Affairs, she pledged to negotiate an end to the nuclear programs in Iran and North Korea; secure all nuclear materials in her first term; establish a nuclear fuel bank; negotiate an accord to verifiably reduce US and Russian arsenals; and, finally, seek Senate approval of the Comprehensive Test Ban by 2009, the tenth anniversary of the Senate's initial rejection of the treaty.
None of the candidates has a simple solution to the nuclear dangers posed by Pakistan, and for good reason— there is none. Senator Clinton, for example, proposed cooperation among the US, Britain, and Pakistan to secure its nuclear weapons. Pakistan im-mediately rejected the idea. Senator Obama's opponents jumped on him for saying he would use US forces to strike at bin Laden in Pakistan if there was reliable intelligence on his location. In fact, most experts (and most candidates) agree that the US should make such a strike; they disagree over whether a commitment to make it should be announced beforehand.
Both McCain and Romney have supported Bush's policy on Pakistan, including continuing to rely on General Musharraf. Huckabee has sharply criticized Musharraf for not doing enough to fight al-Qaeda and he blames Bush for not pushing him hard enough to do so. Obama and Clinton support Musharraf's removal through free elections, with Clinton explicitly saying that the general is not a reliable ally. None of the candidates believe that elections alone will solve Pakistan's problems, and they are right. Any solution must be part of a comprehensive, regional policy that both pursues terrorist groups and reduces the conflicts that give these groups fresh recruits. Such a policy should aim to reduce and secure all nuclear weapons and materials, including India's, so Pakistan is not singled out.
The efforts to work out such a comprehensive approach, at least by the Democratic candidates, have been encouraged by a bipartisan appeal from Republicans George Shultz and Henry Kissinger and Democrats William Perry and Sam Nunn in two Wall Street Journal Op-Ed articles: "A World Free of Nuclear Weapons," published on January 4, 2007; and "Toward a Nuclear-Free World," published on January 15, 2008. Since the publication of the first article, the four veteran cold warriors have mounted a campaign for their ideas with conferences, testimonies, and publications. They have secured the support of 70 percent of the still-living former secretaries of state and defense and national security advisers, including James Baker, Colin Powell, Melvin Laird, and Frank Carlucci. They want the United States government to recommit itself to the goal of eliminating nuclear weapons and to embrace a concrete plan of action to achieve this goal. In so doing, they have created a new political space for many officials, including the Democratic front-runners, to advocate more ambitious and far-reaching arms-reduction policies.
For the first time since the initial efforts of the Truman administration in the 1940s, a movement to eliminate nuclear weapons has developed not from the political left but from the "realist" center of the security elite. This promises to give the cause of arms reduction a political plausibility and importance that previous efforts, including the broad-based Nuclear Freeze Movement of the 1980s, have lacked. Whether these efforts will succeed in their ultimate goal is far from clear; but if the movement can be sustained and gather wider support, this could dramatically reduce threats of nuclear war and nuclear terrorism—the greatest security threats now facing the United States.
—February 7, 2008
 Al-Qaeda's efforts to obtain nuclear expertise from Pakistan are well documented. In the weeks before the September 11 attacks, two retired Pakistani nuclear scientists had several meetings with bin Laden in Afghanistan to discuss nuclear weapons technology. See Kamran Khan and Molly Moore, "2 Nuclear Experts Briefed Bin Laden, Pakistanis Say," The Washington Post, December 12, 2001.
 See Anne Hessing Cahn, Killing Detente: The Right Attacks the CIA (Pennsylvania State University Press, 1998).
 Reagan appears in fact to have been a lifelong believer in arms control; as an actor in 1945 he volunteered to lead a disarmament rally in support of Truman's plan to abolish nuclear weapons. The Warner Brothers studio vetoed the idea.
 "Suicide Bomb Hits Pakistani Bus," BBC News, November 1, 2007.
 Bill Roggio, "Suicide Attack at Pakistani Nuclear Weapons Complex," The Long War Journal, December 10, 2007.
 A plutonium bomb similar to the one used on Nagasaki requires only six to twelve kilograms of plutonium, but has a more complicated design, probably beyond terrorist capabilities. The plutonium core is surrounded by a layer of precisely shaped conventional explosives that compress the core down to the critical mass needed to start the explosion. This was the design tested in the first atomic explosion; scientists were so certain the uranium design would work that the bomb was used without testing.
 Graham Allison, Nuclear Terrorism: The Ultimate Preventable Catastrophe (Times Books, 2004), p. 204. See also Matthew Bunn and Anthony Wier, "Terrorist Nuclear Weapon Construction: How Difficult?," in The Annals of the American Academy of Political and Social Science, September 2006.
 Hillary Rodham Clinton, "Security and Opportunity for the Twenty-first Century," Foreign Affairs, November– December 2007.