For Vice President Dick Cheney, the question of how to deal with would-be nuclear powers in Iran and North Korea is disarmingly simple.

"We don't negotiate with evil; we defeat it,'' Cheney reportedly pronounced, dismissing a State Department bid in late 2003 to make a deal with North Korea. A similar prescription was offered when moderates in the Iranian regime made a secret approach that year to begin talks with the United States.

The long history of the Cold War is replete with the issue of whether -- and how -- to talk with a mortal foe. U.S.-Soviet relations froze time and again. For two decades, there was no dialogue at all with Communist China. But in the end, American policymakers have always chosen the path of negotiation.

For Cheney -- and for President George W. Bush -- sitting down at a table with the likes of North Korea's Kim Jong Il would be an act of weakness, a lessening of American power and prestige that granted undeserved legitimacy to despised regimes.

In recent months, and most prominently last week, the Bush administration has appeared to reverse its stance, opening the door to direct talks with North Korea and Iran.

These moves are carefully constrained, reflecting in part the ongoing divisions in the Bush administration about the advisability of going down this path. Contacts with both regimes will take place only within the framework of multilateral talks and focused solely on the issue of their nuclear programs. One-on-one talks on a broader agenda, including establishing basic diplomatic relations, have been explicitly ruled out, for now.

The decision to talk seems driven in large part by the realization that defeating evil has proven to be more difficult than some in the administration assumed. After Iraq, the use of military force against Iran -- and even more so against a North Korea already probably armed with nuclear weapons -- is highly unlikely. Potential allies in imposing economic and political sanctions -- the Europeans, Russians and Chinese, along with South Korea and Japan -- won't even consider such steps without a greater show of American willingness to negotiate with the evil enemy.

Limited as it is, the significance of this shift has to be seen against the backdrop of deep resistance to such diplomatic engagement in the Bush administration.

"There is a fundamental disagreement over how to approach the North Korea problem,'' explained Richard Armitage, who served as deputy secretary of state from 2001-05.

"'Those of us at the State Department concluded: From the North Korean point of view, the nuclear issue is the only reason we Americans talk with them,'' Armitage recounted in a recent interview with the Oriental Economist newsletter. "Therefore, the North Koreans would be very reluctant to let go of the nuclear program. We knew it was going to be a very difficult process. But you have to start somewhere. You start by finding out what their needs and desires are, and seeing if there is a way of meeting those needs and desires without giving away something that is sacred to us.''

But the White House and others in the administration blocked at every turn their attempts to open direct dialogue with Pyongyang. "There is a fear in some quarters, particularly the Pentagon and at times in the vice president's office, that if we were to engage in discussions with the North Koreans, we might wind up with the bad end of the deal,'' Armitage said. "They believe that we should be able to pronounce our view, and everyone else, including the North Koreans, should simply accept it. This is not a reasonable approach.''

Six-party talks

The compromise was the decision, through the good offices of China, to convene six-party talks that included surrounding countries such as Russia, South Korea and Japan. Administration officials have argued that this format rallies others to back the United States in pressing the North Koreans, effectively isolating them.

The same argument was made for the United States to support, but not directly join, until this past week, European negotiations with Iran. As recently as April, Bush was still publicly wedded to this logic.

"With the United States being the sole interlocutor between Iran, it makes it more difficult to achieve the objective of having the Iranians give up their nuclear weapons ambitions,'' Bush said in answering questions following an April 10 speech. "It's amazing that when we're in a bilateral position, or kind of just negotiating one on one, somehow the world ends up turning the tables on us.''

Arguably, however, the opposite has been true. In the case of Iran, the Europeans, including Great Britain, have consistently urged the United States to talk directly to Iran.

An excuse not to talk

All the other partners in the six-party talks, including the closest U.S. ally, Japan, have held their own direct talks with Pyongyang and pushed the United States to do the same. Ultimately, it is the United States that has found itself isolated.

North Korean experts in the State Department had warned against relying only on this approach.

"In the case of negotiating with North Korea, more is not merrier and certainly not more efficient,'' says Robert Carlin, a longtime CIA and State Department intelligence expert on North Korea who participated in virtually all negotiations with the North from 1993-2000. "The more parties and people at the table, the greater the likelihood of posturing, and the harder it is to make concessions.''

In his view, the insistence on a multilateral approach was initially an excuse not to talk. "They didn't want bilateral talks with Pyongyang and they certainly didn't trust the State Department to conduct any such thing.''

These divisions have persisted. Last September, with the backing of Secretary of State Condoleezza Rice, the State Department's chief negotiator was finally allowed to meet his North Korean counterpart. This led to an agreement in the six-party talks last September, a compromise that conceded in principle the North Korean right to have a nuclear power reactor.

That deal prompted a backlash from Cheney and others, according to senior officials within the administration, and fresh curbs on direct contacts with Pyongyang. But the new proposal to Iran apparently also includes an offer to supply power reactors.

What still has resonance is the belief that direct talks with North Korea and Iran amount to acceptance of the regimes in power in both countries.

Resistant to deal

"Ultimately the president is, on this issue, very, very resistant to the idea of doing a deal, even a deal that would solve the nuclear problem,'' Flynt Leverett, who dealt with Iran for the Bush National Security Council, said in a recent interview. "You don't do a deal that would effectively legitimate this regime that he considers fundamentally illegitimate.''

The administration may calculate that this offer of talks will only serve to isolate Iran and shore up ties with Europe. But it may have stepped onto a slippery slope toward a bargain that will necessarily involve painful concessions to Iran and lead toward a resumption of diplomatic relations broken off almost three decades ago.

Opposition to negotiating with the enemy is deeply embedded in the Bush administration. There is, however, a precedent for a sea change -- Ronald Reagan. President Reagan came to office in the wake of the Soviet invasion of Afghanistan and the American boycott of the 1980 Moscow Olympics. Dialogue with the Soviets was halted and the staff of the Reagan National Security Council opposed any contacts with Moscow.

Reagan himself, in a famous 1983 speech, referred to the Soviet Union as an ``evil empire,'' followed two weeks later by the launching of the "star wars'' missile-defense program. Soviet leaders, we learned later, were convinced that the United States might launch a first strike. In August of that year, Soviet fighter aircraft shot down a Korean Airlines passenger jet that had strayed from its flight path, a sign of sharply increasing tension.

In the Reagan administration, against fierce internal opposition, Secretary of State George Shultz pushed to resume dialogue with the Soviets, beginning with achievable steps such as resuming grain sales. Reagan ultimately agreed, starting down a road that led to the series of dramatic summits from 1985 with incoming Soviet leader Mikhail Gorbachev.

Reagan's willingness to sit down with the "evil'' foe flowed from a sense of conviction in American strength. It is not yet evident that his Republican successor shares the same sense of confidence.

North Korea's nuclear facility at Yongbyon, which had been "frozen" under international inspection since 1994, was reactivated this January for the production of plutonium. Just last week the North Koreans announced that they intended to use the resulting plutonium to make nuclear weapons, which only confirmed what we always believed.

If it keeps on its present course, North Korea will probably have six to eight nuclear weapons by the end of the year, will possibly have conducted a nuclear test and may have begun deployment of some of these weapons, targeted against Japan and South Korea. By next year, it could be in serial production of nuclear weapons, building perhaps five to 10 per year.

This is a nightmare scenario, but it is a reasonable extrapolation from what we know and from what the North Koreans have announced. The administration to this point has refused to negotiate with North Korea, instead calling on the countries in the region to deal with the problem. The strategy underlying this approach is not clear, but the consequences are all too clear. It has allowed the North in the past six months to move from canned fuel rods to plutonium and, in a few more months, to nuclear weapons. And the consequences could extend well beyond the region. Given North Korea's desperate economic condition, we should expect it to sell some of the products of its nuclear program, just as it did with its missile program. If that happens, a nuclear bomb could end up in an American city. The administration has suggested that it would interdict such transfers. But a nuclear bomb can be made with a sphere of plutonium the size of a soccer ball. It is wishful thinking to believe we could prevent a package that size from being smuggled out of North Korea.

How did we get into this mess?

For several decades North Korea has aspired to have nuclear weapons. During that period successive administrations have, through a combination of threats and inducements, curtailed their program but never their aspirations. In the late 1980s the first Bush administration saw the potential danger and persuaded the Soviet Union to pressure North Korea to join the nuclear Non-Proliferation Treaty and subject its nuclear facilities to international inspection. The North Koreans complied, but they stalled long enough to give them time to make and store enough plutonium for one or two nuclear bombs before the inspectors arrived.

Shortly after the Clinton administration took office, they tried again. As spent fuel was being taken from the nuclear reactor at Yongbyon, the North Koreans ejected the inspectors and began preparations for reprocessing. This would have given them enough plutonium for five or six additional nuclear bombs. President Clinton considered this sufficiently dangerous that he declared reprocessing a "red line." In response, I had the Joint Chiefs prepare a plan to use military force if necessary to prevent this outcome. When Kim Il Sung offered to negotiate the issue, Clinton responded that he would negotiate only if the North Koreans froze all activity at Yongbyon during the negotiation. In the end, military force was not necessary. The agreement that ended this crisis was far from perfect, but in its absence North Korea could today have 50 to 100 nuclear weapons.

But the North Koreans never gave up their desire for nuclear weapons. Even as they complied with the freeze at Yongbyon, they covertly started a second nuclear program at a different location. American intelligence discovered signs of this program and last fall confronted the North Koreans, who did not dispute the charge. The administration responded by stopping fuel oil deliveries called for under the old agreement, to which the North Koreans responded by reopening Yongbyon and racing to get nuclear weapons.

There are three basic approaches for dealing with this dangerous situation. The administration can continue to refuse to negotiate, "outsourcing" this problem to the concerned regional powers. This approach appears to be based on the hope that the regional powers will be able to prevail on North Korea to stop its nuclear program. But hope is not a strategy. If their hopes are not realized and North Korea continues on its present course, it will soon have a significant nuclear arsenal. And while the regional powers could play a role in resolving this crisis, they are unlikely to succeed in the absence of a clear American negotiating strategy in which they can participate.

A second alternative is to put economic pressure on North Korea and hope for "regime change." Or the United States could take military action to bring this change about. But while the regime may one day collapse, with or without economic pressure, there is no reason to believe that it will happen in time - the nuclear threat is imminent. Taking military action to force a timely regime change could result in a conflict comparable to the first Korean War, with casualties that would shock the world.

The third alternative is to undertake serious negotiations with the North Koreans to determine if there is a way to stop their nuclear program short of war. The administration is clearly reluctant to negotiate with the North Koreans, calling them loathsome and cheaters. It is easy to be sympathetic with this position; indeed, the only reason for considering negotiation with North Korea is that the other alternatives are so terrible. The administration, seeing the danger, has said that it "would not tolerate" a North Korean nuclear arsenal. The North Koreans responded to this declaration by accelerating their program. The conflict between our views and their actions is a formula for drifting into war. It is imperative that we stop that drift, and the only clear way of doing that is by negotiating.

Any negotiations with the North Koreans are likely to be difficult and protracted, so they should be predicated on a prior agreement that North Korea will freeze its nuclear activities during the negotiations. For negotiations to have a chance of success, they would need to have a positive dimension, making it clear to North Korea that forgoing nuclear weapons could lead it to a safe and positive future. But they would also need a negative or coercive dimension, both to induce North Korea to take the right path and to give us and our allies more credible options if diplomacy should fail. President Kennedy said it best: "We should never negotiate from fear, but we should never fear to negotiate."

The nuclear regime in place since the Nonproliferation Treaty (NPT) took effect in 1970 is broken and needs to be fixed, the world's highest-ranking nuclear official told a half-full Memorial Auditorium in a wide-ranging lecture about the future of nuclear energy and weapons yesterday afternoon.

"We have a dysfunctional system -- system that cannot endure," said Mohamed ElBaradei, the director general of the International Atomic Energy Agency (IAEA). "We're reaching the fork in the road. Events in the last few years have made it clear that we need to change course."

The big news from ElBaradei's speech was his support for American entreaties to Iran. But the 2005 Nobel Peace Prize recipient also commented on North Korea, India, Pakistan, Iraq, terrorism, disarmament and the future of nuclear energy.

He said there are probably eight current nuclear states, excluding North Korea. He worried aloud that countries which can currently produce nuclear energy peacefully are only six months away from developing nuclear weapons for military purposes.

"Acquiring the technology to enrich uranium or reprocess uranium basically is the key to develop nuclear weapons as we have seen in Asia and Iran," he said. "They are virtually weapons states because in six months time if they decide for security reasons to develop their own weapon, they are there."

Iraq

While not a household name, ElBaradei was a prominent figure in the news as the lead weapons inspector in Iraq during the run-up to the 2003 American invasion. He said at the time that he could not find evidence of Iraqi weapons of mass destruction, but he would not conclude that there were no weapons in the country or that Saddam Hussein did not have a program.

ElBaradei asked for more time to complete inspections, but the Bush administration declined his request and decided to invade. The U.S. never found the nuclear and biological material that some had promised existed.

"Luckily...well I'm not sure luckily...we were proven right that there was no nuclear or any weapon of mass destruction in Iraq," he said. "But I hope that all of us have learned from the Iraq experience that we cannot just jump the gun. You have to be absolutely sure of the facts."

India

ElBaradei surprised observers when he supported the U.S. agreement with India earlier this year, which allowed the country to continue developing nuclear weapons and energy. He said the agreement with India did not endorse its proliferation activities but was indicative of the kind of outside-the-box thinking the international community needs when considering the spread of nuclear weapons and material.

"The end result is India coming closer and working with the rest of the world," he said. "It is not a perfect agreement, but it has a lot of advantages. From the safety, security and nonproliferation perspective, I see that agreement as a win-win situation."

Pakistan

Pakistan developed nuclear weapons as a response to India. Some have criticized Pakistan for its poor stewardship and control of the bomb, pointing out that weapons were almost fired during a skirmish over the disputed Kashmir region.

AQ Kahn, a senior nuclear scientist who helped Pakistan join the exclusive nuclear club, was caught selling compact discs and other information about bombs to several other countries.

"How much damage was done in the process we don't know," ElBaradei said.

The release of this nuclear material demonstrates the need for a "more robust verification system," he said, adding that Pakistan has come closer to the international community in recent years.

North Korea

Kim Jong Il expelled all IAEA inspectors in Dec. 2002, withdrew from the NPT in Jan. 2003 and announced in February 2005 that his military had a nuclear deterrent.

"North Korea is still a major problem," ElBaradei said. "We don't talk about it enough, but North Korea is declaring right now that they have a nuclear weapon. And the longer that they continue to be in that status, the more it is accepted in the collective conscious. This would be terrible because it will have a lot of negative ramifications in South Korea and Japan."

ElBaradei said ongoing negotiations are an important development but more needs to be done.

"What we see with the current six-party talks should have taken place years ago," he said.

Nuclear Proliferation

ElBaradei stressed that he understands the value of nuclear power, which produces much of the developed world's energy. Reducing its use would create more dependence on greenhouse gas-creating fossil fuels, he said.

"We need to use nuclear energy responsibly to maximize benefit and minimize risk," he said.

He said his "number one nightmare scenario" is a terrorist group acquiring nuclear technology since terrorists are not deterred by the possibility of reprisal.

In the post-Cold War world, ElBaradei said he could see no justification for the U.S. and Russia to maintain their nuclear arsenals on ready alert to fire with thirty minutes notice. He called on America to lead by example and continue to disarm its nuclear stockpile.

"Rather than pass judgment, I'd definitely like to say the U.S. should do more in leading by example in terms of nuclear disarmament," he said.

In September 2005, ElBaradei was reappointed to a third term as director general of IAEA. The United States had considered holding up his nomination but dropped its objections under pressure from European allies, who admire the former law professor from New York University.

Diplomat to the Core

The Egyptian native's sometimes broken English was interspersed with self-corrections and careful legalese nuance. ElBaradei answered questions posed by Political Science Prof. Scott Sagan, the director of the Center for International Security and Cooperation.

When Sagan made bold pronouncements about different country's nuclear activities, including the United States' "colossal failure" when North Korea violated the NPT, ElBaradei seemed careful not to point fingers, play the blame game or make enemies. Nonetheless, for a senior United Nations official, his speech was notably blunt.

"There's no international public servant whose integrity and work I admire more than yours," Sagan told ElBaradei.

Accompanied by his wife, ElBaradei spent the day at the University visiting with faculty and students. He spoke at a lunch sponsored by the Freeman Spogli Institute for International Studies and traveled to Sagan's home for a dinner with invited guests. He left the area at 8:30 p.m.

Iran has climbed to No. 1 on the Washington crisis hit parade. The question of how to stop Iran's nuclear program has unleashed a torrent of punditry. Advocates of diplomacy and a military strike spar on television and in op-ed pages.

Iran's nuclear ambitions deserve our attention. But even by the most alarmist estimates, Iran is years away from being able to build a nuclear warhead.

Meanwhile, over in Northeast Asia, North Korea now has enough fissile material for five to seven weapons and is quietly churning out enough plutonium to build at least one warhead a year, according to rough intelligence estimates. More ominously, work is moving ahead on a new reactor that could potentially produce enough separated plutonium for up to 10 weapons a year.

Somehow this danger prompts no sense of urgency in Washington. After a promising breakthrough last September, the six-party talks to halt the program have lapsed into a stalemate that is close to total collapse.

The Bush administration seems unconcerned. Diplomacy has ground to a halt. The North Koreans refuse to return to the six-party talks. The White House has barred its chief negotiator from talking directly with them, despite Pyongyang's desire to meet and the urging of our six-party partners.

Administration officials have recently floated a report that they are considering a new initiative to negotiate a peace treaty with North Korea. This is a smoke-screen to conceal an empty North Korea policy. According to administration officials, the peace treaty idea has been kicking around for months without going anywhere. South Korean officials tell me that they have been waiting, so far in vain, for any serious detailed discussion of this proposal.

It is the president himself who opposes direct negotiations with Pyongyang, over anything, including a peace treaty. He sees direct talks with North Korea or Iran as an act of weakness. "Somehow,'' he said last month, "the world ends up turning the tables on us.''

In reality, the administration is content to pursue a strategy of going after North Korean counterfeit currency and production of amphetamines and cigarettes, hoping to cut off the flow of funds from these activities. According to administration officials, Under Secretary of State Robert Joseph, the driving force behind this policy, gleefully talks about ``turning out the lights'' in Pyongyang.

Administration officials claim they are drying up slush funds that North Korean dictator Kim Jong Il uses to buy the loyalty of his subordinates. Some even suggest this could trigger a coup against Kim, with the Chinese pulling the strings.

But American intelligence experts who monitor North Korea closely see little evidence to support the conclusion that North Korea is being brought to its knees. Even if the measures are drawing blood, it is self-delusional to believe that this will bring down a regime that has already proven it is willing to starve its own population to stay in power.

The administration seems intent as well on pressing China and South Korea to curb their trade and investment with the North. The administration's special envoy on human rights in North Korea, Jay Lefkowitz, seems to spend most of his time attacking the South for setting up an industrial park in Kaesong in the North. He portrays it as exploiting slave labor. The South Koreans defend it as a vehicle to bring capitalism into the communist North.

The Bush administration's combination of attempted coercion and diplomatic freeze has only two visible effects so far.

First, it lends credence to North Korean claims that the United States, contrary to the joint statement issued last September, is still intent on overthrowing their regime.

Second, it undermines gains made by allowing chief envoy Christopher Hill to hold direct talks with his North Korean counterparts. That demonstrated a flexibility and confidence that disarmed critics, particularly in South Korea, and isolated the North. It strengthened coordination with China and South Korea, the two players with the most leverage over the North.

Now officials in both those capitals again question American readiness to seriously negotiate. Beijing and Seoul are even more convinced that pushing market reforms is the only route to bring the North to give up its nuclear option. Next month former South Korean President Kim Dae Jung will revisit his historic summit with the North Korean leader in 2000.

This growing gap with our allies and partners is deadly. Even if we wanted to opt for coercion, the United States can't do so alone. For that reason, it is urgent that the United States regains the diplomatic upper hand.

President Bush could hardly have picked a more critical time to host China's President Hu Jintao at the White House.

A flare-up in troubled waters between South Korea and Japan, faltering trilateral cooperation among the US, Japan, and South Korea, and the failure to persuade North Korea to come close to terms on its nuclear-weapons program all make China a pivotal player -- while raising questions about US strength and influence in the region.

"The United States can play a more profound role in stabilizing the region," says Moon Jung In, international relations professor at Yonsei University in Seoul. "China may be happy to see what's happening."

While the United States tries to persuade China both to reduce its yawning trade surplus with the US and get North Korea to return to six-party talks, a potentially explosive quarrel between South Korea and Japan is frustrating Washington's efforts to join its two northeast Asian allies in common cause on the nuclear issue.

"High-ranking officials of the South Korean government have been talking about Korean-US cooperation rather than trilateral cooperation," says Kim Sung Han, director of North American studies at the Institute of Foreign Affairs and National Security, affiliated with South Korea's Foreign Ministry.

"Trilateral cooperation is vital to resolving the North Korean problem," he says.

The tendency in Korea is to blame Japan for somehow wishing to assert its own role in the region, reminding both Koreans and Chinese of the history of Japanese imperialism in Asia, culminating in the conquest of much of the Chinese mainland and 35 years of colonial rule over the Korean peninsula.

Who lays claim to islands?

Memories of that history have leaped into the headlines as a result of a stand-off midway between Korea and Japan in what Koreans call the East Sea and the much of the rest of the world knows as the Sea of Japan.

The focal point is a cluster of 34 islets, basically uninhabitable, that both Korea and Japan claim as part of their national territory.

Korea calls the cluster "Dokdo," or "Solitary Island," while Japan calls it "Takeshima," or "Bamboo Island," and Japan also wants to give Japanese names to undersea rock formations surrounding the islands, basically volcanic rock thrust up from the sea.

The issue, simmering for years, reached a boiling point this week when Japan said it was sending two survey vessels to chart the waters around the islands, held by a garrison of Korean troops seen on Korean television manning anti-aircraft weapons and machine-guns as if to stave off enemy invasion.

Eager to prove his fearlessness in the face of the Japanese, South Korea's President Roh Moo-Hyun has ordered 18 patrol boats to form a blockade against the survey vessels.

"Some people are claiming territorial rights to former colonies that were once acquired through war and aggression," he told Christian leaders at a breakfast Thursday. Not just "good will," he said, as if preparing for war, but "wisdom and courage" were needed in such a crisis.

Shinzo Abe, Japanese government spokes-man, says the vessels are going there in defiance of a pledge of "stern action" by Korea's foreign minister, Ban Ki Moon, against any "provocation" by Japan.

Mr. Kim, of the Institute of Foreign Affairs and National Security, accuses Mr. Abe, an outspoken conservative who aspires to succeed Junichiro Koizumi as Japan's prime minister, of playing to the right-wing in refusing to address Korean sensitivities.

"Shinzo Abe has his own agenda," says Kim. "The Japanese are trying to increase their own role in the area of security. This is sending conflicting messages."

The sense here is that the US could rein in Japan but is reluctant to do so while cooperating closely with Japan on North Korea.

"The United States has been rather silent on these issues," says Kim Tae Hwan, research professor at Yonsei University. "Koreans have been very uncomfortable with the Japanese posture of aligning with the United States. Japan seems to disregard expectations from Korea."

While playing into the hands of China, the standoff over the islands also comes at an opportune moment in terms of South Korea's policy of rapprochement with North Korea.

Ministerial talks between North and South

South Korea's unification minister, Lee Jong Seok, goes to Pyongyang Friday for the first ministerial-level talks between North and South Korea in five months. He and his North Korean opposite number will have no trouble agreeing on the need to fend off what North Korea has already denounced as a "shameless" attempt at expansion.

It's a "very clear win-win" for both North and South Korea, says David Kang, a professor at Stanford University's Shorenstein Asia-Pacific Research Center. In the process, he says, the ruckus at sea "makes it look a lot as if Korea and China are cooperating more since they're both upset by Japan's moves."

Mr. Kang sees the standoff as "a distraction" that probably will not have "a fundamental effect on North-South Korean relations," but adds to the sense that six-party talks on North Korea's nuclear weapons are not likely to go anywhere.

"The US doesn't expect to make any progress on six-party talks," says Kang. "Nobody has a face-saving way out."

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

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

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

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

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

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

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

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

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

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