The American Academy of Arts and Sciences has published a paper with seven essays from leading scholars invited to respond to Scott Sagan's concluding essay Shared Responsibilities for Nuclear Disarmament in the Fall 2009 special issue of Daedalus on the global nuclear future. The paper includes Sagan's original essay and responses by James M. Acton, Jayantha Dhanapala, Mustafa Kibaroglu, Harald Muller, Yukio Satoh, Mohamed I. Shaker and Achilles Zaluar.

As Leslie Berlowitz, CEO of the American Academy of Arts and Sciences, states in an excerpt from the paper's introduction:

"Renewed interest in arms control and restated commitments to the longterm goal of nuclear disarmament have clearly increased over recent years, most dramatically with President Barack Obama's April 2009 speech in Prague. With that change in focus comes an opportunity for the international community to rethink how Article VI of the NPT is traditionally interpreted and to move beyond the cycle of repeated complaints from the 'have-nots' that the 'haves' are not doing enough to disarm themselves and repeated retorts by the "haves" that they are already taking every step that is realistic or prudent. The promise of a different approach to the commitments made under the NPT forms the basis of the Scott Sagan's valuable article--"Shared Responsibilities for Nuclear Disarmament"...

"The differences in national perspectives and the differences in individual opinions about appropriate disarmament steps among the authors should not mask a commitment they all share. The contributors to this volume agree that new thinking and continued debate about how best to maintain momentum toward nuclear disarmament is to be welcomed. Only by seeking out, and taking into consideration, a cross section of views can progress toward the goal of a nuclear-weapons-free world continue... 

"Their contributions serve to expand the discussion that was started by the original Daedalus article--and together they are intended to spark renewed policy debates about how best to pursue global disarmament, debates that will be prominent at the May 2010 NPT Review Conference in New York City and in the years following that important meeting."

Leaders or representatives from 47 countries recently attended the nuclear security summit in Washington. By holding a bilateral meeting with U.S. President Barack Obama and delivering an important speech at the summit, Hu Jintao highlighted China's positive image for people across the globe and helped reverse the deterioration of US-China relations.

Obviously, it takes a long path toward establishing a global mechanism to counter nuclear proliferation and nuclear terrorism. Many of these leaders were not quite sure whether they would come away from the summit empty-handed.

However, they decided to attend the summit mainly to respond positively to Obama, who had launched a number of initiatives to build a nuclear-free world. The same is true for Hu Jintao and his decision to attend the summit.

Hu's visit to Washington will help lead the bilateral relations toward a positive direction. Although some disputes continue between the two countries, Hu's visit to Washington will no doubt contribute to lowering U.S. hostility toward China.

Earlier, the rapid increase in GDP had stimulated some Chinese diplomats to take blind pride in dealing with their foreign counterparts. Now, it is time to rethink whether it is necessary to adhere to the well-established principle of keeping a low profile in handling Sino-American relations.

China's GDP will soon become the second largest in the world. Who is the greatest beneficiary from the pursuance of this principle over the past three decades? Needless to say, it is China.

Now, China is just halfway through its course of "peaceful rise." In the foreseeable future, the United States will remain the No. 1 power in the world. Two decades from now, who will become the greatest beneficiary if China, as the biggest developing country, is able to maintain stable relations with Washington? Obviously, the answer is China.

In his opening statement at the summit, Obama pointed out that in today's world, the world has reduced the risk of a nuclear war between big powers, but the threat of nuclear terrorist assaults is increasing. He is right. Terrorists can penetrate all places throughout the world without leaving a trace.

It is difficult for all major powers, especially the United States, to detect and prevent them from launching assaults including sudden attacks with "dirty bombs" as weapons. As such, the whole world faces the most serious security challenge.

Such a strategic assessment prompted Obama to convene the nuclear security summit as well as his earlier initiative of "a world free of nuclear weapons." Preoccupied by this assessment, he has spared no effort to promote the campaign of countering nuclear proliferation and nuclear terrorism.

To fight nuclear terrorism, the summit focused on establishing an international nuclear security mechanism. The United States and many countries face the threat of nuclear terrorism. China is no exception.

In case the East Turkistan separatists consider the timing is mature to intensify conflicts with Beijing, they will no doubt take whatever means necessary to penetrate nuclear facilities or acquire "dirty bombs." Moreover, the large-scale construction of nuclear power plants in China introduces more security challenges. China will be in the peak period of building such plants in the next two decades.

The ongoing construction of such plants scattered in coastal areas would expose the nation to threat. A terrorist attack on even one plant would result in consequences more serious than that of detonating a nuclear bomb over a city. Taking this into account, Beijing has adopted various measures to strengthen nuclear security in recent years.

As a positive response from China to the international community, Hu Jintao made the decision to attend the summit, which reflects that Beijing and Washington actually are sharing common interests by making joint efforts to establish a global mechanism for countering nuclear proliferation and nuclear terrorism.

This action indicates that Beijing regards nuclear terrorist assaults as a huge threat to national security interests and it hopes to strengthen international cooperation to limit or even eliminate this type of threat.

Also, this decision has indeed enabled China to avert a head-on collision with the United States and helped reverse a deterioration of U.S.-China relations. Based on this, we can suppose that Beijing is able to conduct strategic adjustment at a critical moment and formulate appropriate foreign policies.

The release last week of the Obama administration's Nuclear Posture Review brings long overdue attention to the vital issue of U.S. strategic posture. Issues raised in the NPR and START have reinvigorated a crucial national nuclear dialogue that has been missing.

As the chairman and vice chairman of Congress's bipartisan Strategic Posture Commission, which issued its report last May, we have watched with great interest the administration's steady progress this past year on its Nuclear Posture Review and the START negotiations.

Themes from our report run through the Nuclear Posture Review and are embodied in the new START agreement. While debate and disagreement must be part of the crossfire in this renewed nuclear dialogue, we want to emphasize important dimensions of both the Posture Review and START treaty that figure prominently in our bipartisan report.

Now that the NPR is completed, we see that it is compatible with our recommendations. The review gives a comprehensive and pragmatic plan for reducing nuclear risks to the United States. We believe it offers a bipartisan path forward - while allowing for healthy disagreements on specific issues.

And it incorporates many of our points - such as pursuing a quick and modest reduction of nuclear weapons with Russia and sustaining the nuclear triad of land-based ICBMs, sea-based SLBMs and bombers. It also recognizes that nuclear weapons safeguarded U.S. security during the Cold War by deterring attack and that we will need them for deterrence in the foreseeable future, as long as others also possess them.

We also see that the NPR puts special emphasis, as our report recommended, on improving the nation's complex nuclear infrastructure and enhancing programs to recruit and keep the nation's best scientific minds. The administration's commitment to increase investment in our national laboratories also ensures that they continue their important role in sustaining a safe, secure and effective nuclear arsenal and in solving many other problems facing the nation.

The review is correct to make preventing nuclear terrorism and proliferation the top priority, while also seeking to strengthen deterrence and to reassure U.S. allies and recognizing the importance of strategic stability with Russia and an emerging China. Our commission reached the same conclusions.

The NPR's changes in U.S. declaratory policy - especially the assurance that Washington "will not use or threaten to use nuclear weapons against non-nuclear parties to the Nonproliferation Treaty that are in compliance with their nuclear nonproliferation obligations" - go beyond our recommendation that the U.S. retain "calculated ambiguity."

It is, however, a sensible variation on a theme that the U.S. should support nonproliferation while preserving deterrence for itself and its allies.

We also note that the NPR chose, as we advised, to avoid adopting a "no first use" policy for nuclear weapons while narrowing the scope of possible first use to "extreme circumstances" - language that was in our bipartisan report.

We believe that the substantial edge the U.S. has developed in conventional military capabilities, which the NPR notes, permits this country to sharply reduce reliance on nuclear weapons. But we caution those who make light of this major U.S. strategic advantage and its implications.

We support the NPR's call for the U.S. not to develop new nuclear weapons now. Our report similarly called for a case-by-case approach to extending the life of today's warheads. And we agree that the focus should be on safety, security and reliability - not developing new military capabilities.

The NPR echoes our call to negotiate a worldwide end to the production of new fissile materials - the key ingredients of nuclear weapons.

Our final report strongly endorsed the U.S. deterrence policy to cover our allies and partners with the U.S. nuclear umbrella - an objective the NPR also embraces.

The report suggested deploying proven missile defenses against threats such as North Korea and Iran but emphasized, as the NPR does, that these defenses should not be so big as to encourage Russia to add warheads to counter them, which would only undermine efforts to reduce nuclear weapons. We included China as well as Russia in this.

But in two areas, we believe the NPR might have fallen short of the mark.

First, we understand that the review considered declassifying additional information about the size and composition of the U.S. nuclear stockpile. It should have done so. This would demonstrate U.S. leadership on the transparency that is needed to secure nuclear materials globally and to bolster strategic stability with Russia and China.

Second, the NPR called for the consideration of conventional "prompt global strike" capabilities. But it did not explain whether these systems would have a niche role against small regional powers such as North Korea or be an ultimate substitute for nuclear weapons in deterrence with Russia and China.

We feel the former is the only sensible approach. Keeping this issue ill-defined creates needless anxiety in Moscow and Beijing that could lead to future problems.

Even with these two caveats, the 2010 Nuclear Posture Review makes important strides in charting a sustainable bipartisan path forward for the United States.

Healthy disagreement over some NPR specifics should not obscure the valuable contribution it makes to advancing U.S. security interests - resting, as it does in part, on our bipartisan 2009 Strategic Posture Commission report.

William J. Perry served as secretary of defense in the Clinton administration. He was chairman of the Congressional Commission on the Strategic Posture of the United States. James R. Schlesinger was the nation's first energy secretary and served as secretary of defense from July 1973 to November 1975. He was vice chairman of the Congressional Commission on the Strategic Posture of the United States.

THIS has been a remarkable time for the Obama administration. After a year of intense internal debate, it issued a new nuclear strategy. And after a year of intense negotiations with the Russians, President Obama signed the New Start treaty with President Dmitri Medvedev in Prague. On Monday, the president will host the leaders of more than 40 nations in a nuclear security summit meeting whose goal is to find ways of gaining control of the loose fissile material around the globe.

New Start is the first tangible product of the administration's promise to "press the reset button" on United States-Russian relations. The new treaty is welcome. But as a disarmament measure, it is a modest step, entailing a reduction of only 30 percent from the former limit - and some of that reduction is accomplished by the way the warheads are counted, not by their destruction. Perhaps the treaty's greatest accomplishment is that the negotiations leading up to its signing re-engaged Americans and Russians in a serious discussion of how to reduce nuclear dangers.

So what should come next? We look forward to a follow-on treaty that builds on the success of the previous Start treaties and leads to significantly greater arms reductions - including reductions in tactical nuclear weapons and reductions that require weapons be dismantled and not simply put in reserve.

But our discussions with Russian colleagues, including senior government officials, suggest that such a next step would be very difficult for them. Part of the reason for their reluctance to accept further reductions is that Russia considers itself to be encircled by hostile forces in Europe and in Asia. Another part results from the significant asymmetry between United States and Russian conventional military forces. For these reasons, we believe that the next round of negotiations with Russia should not focus solely on nuclear disarmament issues. These talks should encompass missile defense, Russia's relations with NATO, the Conventional Armed Forces in Europe Treaty, the Intermediate-Range Nuclear Forces Treaty, North Korea, Iran and Asian security issues.

Let's begin with missile defense. Future arms talks should make a serious exploration of a joint United States-Russia program that would provide a bulwark against Iranian missiles. We should also consider situating parts of the joint system in Russia, which in many ways offers an ideal strategic location for these defenses. Such an effort would not only improve our security, it would also further cooperation in dealing with the Iranian nuclear threat, including the imposition of consequential sanctions when appropriate.

NATO is a similarly complicated issue. After the cold war ended, Russia was invited to NATO meetings with the idea that the country would eventually become an integral part of European security discussions. The idea was good, but the execution failed. NATO has acted as if Russia's role is that of an observer with no say in decisions; Russia has acted as if it should have veto power.

Neither outlook is viable. But if NATO moves from consensus decisions to super-majority decisions in its governing structure, as has been considered, it would be possible to include Russia's vote as an effective way of resolving European security issues of common interest.

The Russians are also eager to revisit the two landmark cold war treaties. The Conventional Armed Forces in Europe Treaty enabled NATO and Warsaw Pact nations to make significant reductions in conventional armaments and to limit conventional deployments. Today, there is still a need for limiting conventional arms, but the features of that treaty pertaining to the old Warsaw Pact are clearly outdated. Making those provisions relevant to today's world should be a goal of new talks

Similarly, the 1987 treaty that eliminated American and Soviet intermediate-range ballistic missiles was a crucially important pact that helped to defuse cold war tensions. But today Russia has neighbors that have such missiles directed at its borders; for understandable reasons, it wants to renegotiate aspects of this treaty.

Future arms reductions with Russia are eminently possible. But they are unlikely to be achieved unless the United States is willing to address points of Russian concern. Given all that is at stake, we believe comprehensive discussions are a necessity as we work our way toward ever more significant nuclear disarmament.

William J. Perry, a senior fellow at the Freeman Spogli Institute for International Studies, was the secretary of defense from 1994 to 1997. George P. Shultz, the secretary of state from 1982 to 1989, is a distinguished fellow at the Hoover Institution.