The article by Daniel Kleppner, Frederick Lamb, and David Mosher (Physics Today, January 2004, page 30) summarizes the results of the excellent American Physical Society study released in July 2003 on boost-phase options for national missile defense.1 The study represents one of the most authoritative analyses to date on the subject and will enhance the quality of the public debate on missile defense for years to come. However, although I agree with many of the study's conclusions, the overall assessment is somewhat pessimistic, especially with respect to the feasibility of intercepting solid-propellant intercontinental ballistic missiles.

My analysis of airborne intercept options suggests that first-generation airborne boost-phase interceptors (ABIs) carrying 90-kg kinetic-kill vehicles should be effective against liquid-propellant ICBMs. It also suggests that second-generation ABIs with 50-kg KKVs could be effective against solid-propellant ICBMs, provided the ABIs can get within approximately 500-600 km of the ICBM launch site, which is possible for relatively small states such as North Korea.2

ABIs have the advantage that they can contribute to an effective theater missile defense--an important mission given the widespread proliferation of short- and medium-range ballistic missiles. In fact, ABIs are the only form of terrestrial boost-phase intercept that can be effective against very short burn-time ICBMs or short-range ballistic missiles because, if necessary, ABI launch platforms can fly over an opponent's territory. Neither ground-based nor naval-based interceptors have that option.

One should also note that ABI systems pose very little threat to the strategic nuclear forces of the five major nuclear powers; hence, they are not nearly as destabilizing as other forms of missile defense. To the extent that one takes seriously the rhetoric of sharing US ballistic missile defense technology, ABI systems can be transferred because they do not threaten US or allied strategic forces.

The difference between my conclusions and those of the APS study arises from different technical assumptions that result, in my case, in greater intercept ranges. In particular, I assumed that an airborne X-band radar can be built within the next decade, which, for favorable geographies like North Korea, can reduce target-detection and tracking delays by as much as 10 to 15 seconds compared to those in the APS study. I also made the assumption, based on the burn times for existing US and Russian solid-propellant ICBMs, that solid-propellant ICBMs have a nominal burn time of 180 s; the APS study assumed a 170-s burn time based on US solid-propellant submarine-launched ballistic missile technology. Also, airborne missiles can accelerate faster; hence, they can have higher average flight speeds compared to surface-based interceptors (on which the APS study focused) because the drag force is lower at high altitudes.

Nevertheless, solid-propellant ICBMs are very difficult targets. Successful intercept will require sensor architectures that push the limits of target detection and tracking, and large (1500 kg), high-speed (6.0 km/s ideal velocity) two-stage airborne interceptors carrying lightweight KKVs. While 50-kg KKVs stretch the limits of what currently is possible, solid-propellant ICBMs stretch current offensive threat possibilities. Neither may be far-fetched 10 years from now.

ABIs do have drawbacks. However, none of them are so severe as to eliminate ABIs from consideration as a viable component of a future US missile defense architecture. In fact, airborne intercept is probably the most attractive boost-phase missile defense option.

Preferences regarding boost-phase ballistic missile defense often have more to do with different threat assessments, operational and political issues, and cost than with technical disagreements. I see no serious technical barrier to an effective ABI system. Nevertheless, the decision to proceed with any form of ballistic missile defense, ABIs included, should be based on an assessment of the system's priority relative to such other important US security concerns as countering terrorism and modernizing conventional forces. From this perspective, the US currently is spending too much on ballistic missile defense.

References

1. D. K. Barton et al., Report of the APS Study Group on Boost-Phase Intercept Systems for National Missile Defense: Scientific and Technical Issues, July 2003; available at http://www.aps.org/public_affairs/popa/reports/nmd03.cfm.

2. See D. A. Wilkening, Science and Global Security, (in press).

Those advocating nuclear arms control and nonproliferation have few reasons for optimism and many reasons for concern, with obstacles including a lack of public interest in the issue; inadequate security controls at facilities storing nuclear-weapons materials; the threat posed by rogue nations such as Iran and North Korea; and the Bush administration's opposition to the Comprehensive Test Ban Treaty banning nuclear weapons testing.

These and other challenges were explored at a special CISAC workshop on "Arms Control and Nonproliferation: Past Triumphs, Future Prospects," held June 1 at SIIS. The event honored George Bunn -- a nuclear nonproliferation pioneer and consulting professor at CISAC -- on the occasion of his 79th birthday. The workshop, which drew more than 120 attendees, was moderated by CISAC co-director Christopher F. Chyba and featured presentations by four expert panelists who have worked closely with Bunn. They included his son Matthew, a senior research associate for Harvard University's Project on Managing the Atom.

As the first presenter, Matthew Bunn discussed the problem of inadequate security systems to prevent the theft of weapons-grade nuclear materials. Because there are no worldwide standards for protecting such materials, many nations devote inadequate resources to the task. Bunn showed slides of nuclear materials storage facilities with primitive locks, flimsy seals and broken-down fences. He cited Russia as the largest threat, because it has the world's biggest stock of unguarded nuclear-weapons materials. He urged international standards for safeguarding nuclear materials; renewed discussion with Russia on the issue; and the removal of nuclear material from sites where adequate security is not feasible.

In the second presentation, Thomas Graham -- a senior U.S. diplomat who has negotiated numerous major arms-control agreements -- said the nuclear Non-proliferation Treaty was not meant to forever discriminate between nuclear "haves" and "have-nots." Instead, it was designed so that those without nuclear weapons would benefit by receiving peaceful nuclear technology from weapons-producing nations, and guarantees that they would not be attacked. But when the United States shirks its nonproliferation obligations -- as it has done by rejecting the Comprehensive Test Ban Treaty and taking steps to develop new nuclear weapons -- the entire regime is threatened, Graham said. He cited Pakistan and North Korea as the biggest nuclear threats, and said the United States must engage in direct negotiations with the latter.

The next presentation, by Daryl Kimball -- executive director of the Arms Control Association -- addressed prospects for the Comprehensive Test Ban Treaty. Though the treaty has been signed by 171 nations including the United States, it has been ratified by only 113 of those nations -- not including the United States -- and must be ratified by 12 more of the 44 designated "nuclear-capable" nations before the treaty can take effect. Kimball discussed the Bush administration's opposition to the treaty, noting that Bush has sought to remove it from the Senate's agenda. Still, Kimball said he's optimistic that the treaty will ultimately be ratified by the United States and will take effect. He cited increasing international pressure on CTBT "holdout states," and a recent U.S. poll showing that public support for the treaty is at its highest level ever, 87 percent.

John Rhinelander, an attorney who helped negotiate the ABM Treaty and SALT I agreements, discussed the prospects for nuclear weapons in space. The weaponization of space is supported by the Bush administration, he noted, and is a real possibility if the United States follows through on its missile defense program. He predicted that President Bush, if re-elected, would continue to pursue weapons development in space, but said Kerry seemed unlikely to do so if elected.

During a question-and-answer session following the presentations, the panelists offered perspectives on why it is so difficult to get the public's and lawmakers' attention on nuclear non-proliferation issues. The panelists agreed that since the breakup of the Soviet Union, most Americans -- including lawmakers -- no longer perceive nuclear weapons as a serious threat, and they have little knowledge about the existing quantity of nuclear weapons. Matthew Bunn said the problem is, "there is no one whose reelection depends on reducing or securing nuclear weapons." He said nuclear non-proliferation could best be promoted by tying it to the issues of terrorism and homeland security. Rhinelander and Grahm advocated holding Congressional hearings on the issue for the first time in 20 years.

Regarding Israel, India and Pakistan, Graham said those nations -- which produce nuclear weapons but have refused to join the NPT regime -- cannot continue to remain outside the regime. He proposed that the three nations be allowed to join in limited form, in exchange for accepting basic limitations such as no first use and no nuclear testing.

Throughout the event, Bunn was praised by the panelists and moderator; Chyba described him as "the personification of the best that CISAC strives to be." Bunn was the first general counsel for the U.S. Arms Control and Disarmament Agency, helped negotiate the nuclear Non-Proliferation Treaty, and later served as U.S. ambassador to the Geneva Disarmament Conference.

Elizabeth Sherwood-Randall, a senior research scholar with the Center for International Security and Cooperation (CISAC) at the Stanford Institute for International Studies and a senior adviser to CISAC's Preventive Defense Project, has been selected as a 2004 Carnegie Scholar.

The 15 scholars chosen this year by the Carnegie Corporation of New York will each receive up to $100,000 for a period of two years to pursue research. They join 52 others awarded the fellowships since 2000.

"The Carnegie Corporation has a long history of supporting path-breaking work in international security, and I am truly honored to be included in such a distinguished group of scholars," said Sherwood-Randall. "Given the state of the world -- and the fact that there are few foreign and defense policy goals that we can successfully pursue unilaterally -- I intend to use this support to generate new ideas about the leadership of America's key alliances and partnerships."

Sherwood-Randall's research topic is "Transforming Transatlantic Relations: A New Agenda for a New Era." Her study will seek to understand the elements of continuity and change in the global security environment in order to determine whether and how America's most important alliance, the North Atlantic Treaty Organization, can remain relevant and effective. She intends to publish the results of her work in a journal-length article as well as produce policy memoranda and briefings for appropriate officials in the U.S. government and relevant international organizations.

Sherwood-Randall served as deputy assistant secretary of defense for Russia, Ukraine and Eurasia during the first Clinton Administration (1994-1996). She played a key role in creating a cooperative context for denuclearization efforts in Russia, Ukraine, Belarus and Kazakhstan and in establishing security ties with the new states of Central Asia. Prior to her government service, Sherwood-Randall served as co-founder and associate director of the Harvard Strengthening Democratic Institutions Project, as chief foreign affairs and defense policy advisor to Sen. Joseph R. Biden, Jr., and as a guest scholar in foreign policy studies at the Brookings Institution.

Sherwood-Randall received her B.A. from Harvard-Radcliffe Colleges, magna cum laude. She received her doctorate in International Relations from Oxford University, where she was a Rhodes Scholar.

Chosen in a highly competitive process -- from an initial group of 144 nominees, 54 were invited to provide complete proposals -- the 15 selected Carnegie Scholars will explore issues critical to economic growth and human development. These include the American electoral process; political theory of international law; school reform from an international perspective; a reconsideration of the Iran hostage crisis; the logic of suicide terrorism; local control and federal reform of education; how U.S. transatlantic relations can remain relevant and effective; Hispanic students' achievements in elementary education; justice in education; political obligations in World War I America; the rise of far-right extremist groups and the role masculinity plays in their resurgence; the role of the United States in the 21st century; and the rebirth of democracy in Iraq.

"The annual announcement of the Carnegie Scholars is an opportunity to celebrate original and creative thinking on a wide array of social issues important to the Corporation's strategies," said Vartan Gregorian, president of the Carnegie Corporation of New York, who inaugurated the Scholars Program in 1999 to support innovative and path-breaking scholarship.

"Criteria for selection were based on stringent academic standards and the relevance of the project to Corporation program priorities," said Neil Grabois, Carnegie Corporation's vice president and director for strategic planning and program coordination, who facilitated the various levels of deliberations. "The program's definition of excellence incorporates demonstrating intellectual risk-taking, framing unusual questions, possessing the capacity to communicate clearly and effectively on complex themes, and advancing scholarship in the Corporation's programs."

The Carnegie Corporation of New York was created by Andrew Carnegie in 1911 to promote the advancement and diffusion of knowledge and understanding. As a grant-making foundation, the Corporation seeks to carry out Carnegie's vision of philanthropy, which he said should aim to do real and permanent good in the world. The Corporation's capital fund, originally donated at a value of about $135 million, had a market value of $1.8 billion on Sept. 30, 2003. The Corporation awards grants totaling approximately $80 million a year in the areas of education, international peace and security, international development and strengthening U.S. democracy.

Beijing tries to read mixed U.S. signals in Korea diplomacy By John W. Lewis

For the past year China has led the quest for a negotiated solution to the Korean nuclear crisis. It facilitated and hosted three-way talks with the United States and North Korea a year ago this week and two sessions of the six-party talks (adding South Korea, Japan and Russia) in August and February. Its officials crisscrossed the globe to explore potential areas of common interest and compromise and this week hosted North Korean leader Kim Jong Il to explore options for the beleaguered Korean Peninsula. Yet, in each of the formal talks, the Chinese have been discouraged by the minimal results. They are now questioning U.S. intentions toward Korea and, in the longer term, toward China.

Beijing considers the unchecked expansion of North Korea's nuclear weapons to be a real possibility, and its reasoning starts with the record of U.S. policies toward nuclear proliferation. That record, the Chinese argue, is mixed and often contradictory. As a result, China worries that Washington might continue to tolerate the program so long as Pyongyang did not cross key red lines, such as the transfer of nuclear materials to terrorists.

Whatever Beijing's past position on nuclear matters, many senior Chinese now regard nuclear weapons on their border to be a direct threat to their national security and suspect Washington of downplaying that danger. For them, it is no great leap to the conclusion that the unfettered growth of the Korean program might embolden others in Asia, including Taiwan, to acquire nuclear weapons despite verbal opposition from Washington. Beijing's leaders can easily imagine how that nightmarish turn of events would undermine the nation's drive toward modernization and end strategic cooperation with the United States.

Despite the fact that all parties at the six-party meeting in February endorsed the dismantling of the North's nuclear weapons program, the Chinese fear that the talks may be dead in the water. Following that meeting, they began to debate other ways to resolve the crisis. They had already reorganized the leadership team responsible for North Korean affairs, and that team had begun acting to prevent the worst case, including offering further inducements to Kim Jong Il this week. Whereas last fall the talk of deepening U.S.-China cooperation on Korea pervaded the news, now, especially after Vice President Dick Cheney's uncompromising stand on Korea and Taiwan last week, the reverse is occurring.

What China can do in these circumstances is quite limited. Its influence on North Korea is largely determined by what the United States does or doesn't do. By refusing to negotiate on a staged process leading to the eventual dismantlement of Pyongyang's nuclear weapons, Washington has tacitly allowed the North's program to proceed. It has rejected proposals for a temporary freeze, technical talks and any interim steps short of the unconditional and complete ending of the program. The result is virtual paralysis.

Beijing has been able to work with North Korea only when it could find areas of potential compromise between Washington and Pyongyang. It cannot or will not act

alone to exert pressure because this would jeopardize its influence on the North. Contrary to a widely circulated story, Beijing did not cut off energy shipments to North Korea for three days in 2003. Beijing would not take such a counterproductive action when its main influence with the North lies in the kind of quiet diplomacy being practiced this week with Kim Jong Il.

Many in Beijing are beginning to question whether there might be a more promising approach with Pyongyang. Should the Chinese, South Koreans and Russians conclude that making progress toward the common goal of the North's complete nuclear disarmament is out of reach, for example, they reluctantly might translate their joint offer of aid in February into a quid pro quo for a partial agreement, such as a limited freeze, that would allow the situation to stabilize. China could worry that such an independent action could endanger the common front with Washington. At the same time, it could calculate that the United States would be sufficiently pleased with any solution that halted the North Korean nuclear program.

None of these developments may come to pass, of course, but who could have imagined a year ago that Washington would have permitted the situation to deteriorate to the present point?