George Lewis, Frank von Hippel
The ABM Treaty is unlikely to be revived any time soon. But it is possible that restraints on US deployment of ballistic missile defenses could make them seem less threatening to the effectiveness of Russia’s and China’s nuclear deterrents and set the stage for discussions about ways to preserve and even advance nuclear arms control. The proposed restraints are on systems designed to intercept warheads outside the atmosphere. Such systems are of little value in any case because they can be easily deceived by decoys and other countermeasures.
US interest in ballistic missile defense dates back at least to the Soviet Union’s launch of the first artificial earth satellite, Sputnik, in 1957. This feat was a tremendous shock to the United States and elicited many US responses, including the creation of the President’s Science Advisory Committee.
Figure 1. Anti-simulation – making the warhead look like a decoy – is one of many possible countermeasures to BMD hit-to-kill interceptors during the relatively long mid-course period when the warhead is in space and the absence of atmospheric drag makes it impossible to distinguish light from heavy objects. Here, an aluminized balloon is inflated around a warhead to make it indistinguishable to radar from accompanying decoy balloons. The balloons could be of different sizes and shapes. Different surface coatings or small, battery-powered heat sources could be used to make the decoys indistinguishable also to infrared sensors. (Graphic from https://www.ucsusa.org/nuclear-weapons/us-missile-defense/countermeasures#.WwBZlkxFyM8. For a broader and more detailed technical discussion, see, Sessler et al. (2000Sessler, A. M., J. M. Cornwall, B. Dietz, S.Fetter, S. Frankel, R. L. Garwin, K. Gottfried, et al. 2000. Countermeasures: A Technical Evaluation of the Operational Effectiveness of the Planned US National Missile Defense System. Union of Concerned Scientists and MIT Security Studies Program, Cambridge, Massachusetts. [Google Scholar]). Available at: https://www.ucsusa.org/nuclear-weapons/us-missile-defense/countermeasures#.WwBZ-ExFyM8).
Figure 3. The US Navy’s current Standard Missile-3 Block I missile interceptors do not have a large enough range to provide ballistic missile defense coverage of the continental United States. The Navy is, however, about to deploy hundreds of longer-range Block IIA interceptors that, although they likely could be deceived by simple countermeasures, could provide that coverage.
Figure 2. For more than a decade, China appeared satisfied with only tens of nuclear warheads on missiles with ranges long enough to reach the United States. Recently, however, it has begun a buildup, including for the first time multiple warheads on some of its ICBMs. One reason for this buildup may be concerns about thickening U.S. ballistic missile defenses (Kristensen and Norris 2016Kristensen, H., and R. Norris. 2016. “Chinese Nuclear Forces, 2016.” Bulletin of the Atomic Scientists 72 (4): 205–211. doi:10.1080/00963402.2016.1194054.[Taylor & Francis Online], [Web of Science ®], [Google Scholar]and prior years).
Within months, the US Army and Air Force had both proposed antiballistic missile systems; the advisory committee studied the proposals and advised President Eisenhower that the technology of the time was inadequate to the task. Many in Congress, especially Senate Majority Leader Lyndon Johnson, were critical of the administration’s lack of enthusiasm for missile defense. A few years later, presidential candidate John Kennedy was critical as well – but after winning the election, he came around to the position that, in a contest between nuclear offense and defense, the advantages were overwhelmingly on the side of the offense.
In 1966, however, Defense Secretary Robert McNamara revealed that the Soviet Union was deploying missile defenses, at least around Moscow, and possibly more broadly. Political pressure for US defenses became intense. In 1967, Richard Nixon threatened to make the antimissile “gap” an issue in the upcoming 1968 presidential election and, under instructions from Johnson, McNamara announced that the United States would deploy a “light” antiballistic missile system to defend against Chinese missiles. China had just begun development of its first intercontinental missile. It would not be deployed, however, until 14 years later.
McNamara’s “light” Sentinel system had 17 missile-defense sites spread around the country, with 480 long-range Spartan exo-atmospheric interceptors and 192 shorter-range Sprint missiles to provide an additional layer of defense for the system’s eyes – its radars. Since this was before the days of imaging chips and microprocessors, homing, hit-to-kill interceptors were not yet technologically feasible. The interceptors were equipped with nuclear warheads and were to be guided by ground-based radars to explode when they passed near incoming warheads. That the Spartan warhead had a yield equivalent to 5 million tons of TNT suggests the expected miss distance was substantial.
The subsequent history of missile defense includes the expenditure of well over $100 billion on systems that could be neutralized by countermeasures costing millions. It also includes a 30-year period of arms control in the form of the 1972 US-Soviet Anti-Ballistic Missile Treaty (ABM), which limited each side’s ballistic missile defense systems to a level that was insignificant when compared to the other side’s offensive capabilities. Instead of driving offensive capabilities higher, these defensive limits allowed the number of strategic nuclear missiles on each side to be capped – and then dramatically reduced at the end of the Cold War.
In 2002, however, President George W. Bush withdrew the United States from the ABM Treaty. In the past few years, North Korea’s nuclear program and its ever-longer-range ballistic missiles have been driving a US missile defense build-up that is producing Russian and Chinese counter–build-ups of offensive systems. Moscow and Beijing want to make certain that their nuclear deterrents would be effective even after a hypothetical US first nuclear strike.
This is therefore a critical time to reintroduce the idea of arms control – or at least restraint – into the debate over ballistic missile defense policy. Though the ABM Treaty is unlikely to be revived any time soon, it is possible that limits on US missile defenses could once again make the US ballistic missile defense program seem less threatening to Russia and China’s nuclear deterrents and set the stage for discussions about ways to rein in their expansion and hopefully set the stage for reductions in the three countries’ offensive nuclear capabilities. We discuss six approaches to the problem of the impacts of ballistic missile defenses on efforts to limit and reduce offensive nuclear arsenals. We argue that the approach most likely to succeed is a combination of diplomacy and restraint in missile defense deployments.
The rise of the ABM treaty
In 1968, two former members of the President’s Science Advisory Committee made public their criticisms of the Johnson administration’s proposed Sentinel system in a Scientific American article. They pointed out some of the many effective countermeasures to missile defenses that would be possible in outer space, including lightweight balloon decoys as shown in Figure 1, radar-reflecting chaff, and ionization of the upper atmosphere by precursor nuclear explosions that would blind radars (Garwin and Bethe 1968Garwin, R., and H. Bethe. 1968. “Anti-Ballistic Missile Systems.” Scientific American, March, 21–31.https://www.jstor.org/stable/pdf/24925996.pdf?refreqid=excelsior%3Af6f7362ee2438d87a2f3e30a06de8034 [Google Scholar]). The article was read with great attention by many academic physicists who had been infected by the activism of the Vietnam War period and were seeking a public policy issue on which they could bring their expertise to bear.
The Defense Department inadvertently created an audience for these physicist-activists by picking sites for its interceptor-missile batteries in major metropolitan areas. Although the purpose was to maximize the protection afforded to the population, many suburbanites were not enthusiastic about having nuclear missiles as near neighbors. “Not-in-my-backyard” movements arose in several major cities.
When their constituents become interested in an issue, so do members of Congress. The leading physicist-critics found themselves invited to testify about countermeasures and defense-offense arms races, notably before the Senate Foreign Relations Committee.
When the Nixon administration took over in 1969, it ordered the antimissile sites moved away from cities. By then, however, the Senate, with a large Democratic majority, was insisting that the administration respond as well to the physicists’ criticisms of the effectiveness of the system. The response was not convincing and, in 1969, Vice President Spiro Agnew had to cast a tie-breaking vote to pass funding for the first interceptor deployment site. The future of the system seemed dim.
To prevent Soviet ballistic missile defense systems from running free as the US program was truncated, Nixon began negotiations with the Soviet Union on both offensive missile and antiballistic missile systems, and in 1972, two agreements were signed – one capping the build-up of launchers for offensive strategic missiles and the other, the ABM Treaty, limiting ballistic missile defenses.
The rationale for the ABM Treaty was set out in its preamble: “[E]ffective measures to limit antiballistic missile systems would be a substantial factor in curbing the race in strategic offensive arms and would lead to a decrease in the risk of outbreak of war involving nuclear weapons.”
Both sides in this landmark agreement officially accepted the idea that a build-up of missile defenses would stimulate further build-ups of offensive weaponry and potentially destabilize the balance of terror by increasing the advantages accruing to the side that launches a first strike.
Russian President Vladimir Putin has argued both points in the years since the United States withdrew from the ABM Treaty – most recently in his pre-election speech on March 1, when he announced five new long-range nuclear weapon delivery systems and justified them as needed to circumvent US ballistic missile defense (“[Russian] Presidential Address to the Federal Assembly” 2018The Kremlin. 2018. “[Russian] Presidential Address to the Federal Assembly.” March 1, 2018.http://en.kremlin.ru/events/president/transcripts/statements/56957. [Google Scholar]).
China has not spoken out as strongly, but as Figure 2 illustrates has tripled the number of its intercontinental ballistic missile (ICBM) warheads since 2005 and is developing a new multi-warhead mobile ICBM (Kristensen and Norris 2016Kristensen, H., and R. Norris. 2016. “Chinese Nuclear Forces, 2016.” Bulletin of the Atomic Scientists 72 (4): 205–211. doi:10.1080/00963402.2016.1194054.[Taylor & Francis Online], [Web of Science ®], [Google Scholar]).
The ABM Treaty, as modified by a 1974 protocol, limited the Soviet Union and the United States to 100 interceptors each in a single area 150 kilometers in radius. The Soviet Union chose to deploy its interceptors around Moscow, where it had already installed 64 Galosh interceptors similar to the US Spartans (Union of Concerned Scientists 2002Union of Concerned Scientists. 2002. “History of Russia’s Anti-Ballistic Missile (ABM) System.”https://www.ucsusa.org/nuclear-weapons/missile-defense/history-of-russian-missile-defense.html#.Wr1AXWaZPYI. [Google Scholar]). The United States chose to deploy its antiballistic missiles in North Dakota to defend a field of Minuteman ICBM silos. Congress closed that site in 1976, however, because – as a House committee put it – “the utility of Safeguard to protect Minuteman will be essentially nullified in the future” by the Soviet Union’s deployment of multiple-warhead ICBMs (Finney 1975Finney, J. 1975. “Safeguard ABM System to Shut Down; $5 Billion Spent in 6 Years since Debate.” New York Times, November 25.https://www.nytimes.com/1975/11/25/archives/safeguard-abm-system-to-shut-down-5-billion-spent-in-6-years-since.html. [Google Scholar]). The United States, for its part, reacted to the Moscow defense system in exactly that manner. In addition to penetration aids, it deployed multiple warheads on its strategic missiles and targeted more than 100 Minuteman ICBMs and an undisclosed number of Polaris submarine-launched ballistic missiles on the Soviet ballistic missile defense system (Kristensen, McKinzie, and Norris 2004Kristensen, H., M. McKinzie, and R. Norris. 2004. “The Protection Paradox.” Bulletin Of The Atomic Scientists 60 (2): 68–77.[Taylor & Francis Online], [Web of Science ®], [Google Scholar]).
Star Wars
The pause in the US policy debate over ballistic missile defense lasted only a decade, however. In March 1983, President Reagan, faced with massive public opposition from the Nuclear Weapons Freeze Campaign to his administration’s proposed nuclear build-up, announced (Reagan 1983Reagan, R. 1983. “Address to the Nation on Defense and National Security.” Reagan Library, March 23.https://www.reaganlibrary.gov/sites/default/files/archives/speeches/1983/32383d.htm. [Google Scholar]):
Tonight… I am directing a comprehensive and intensive effort to define a long-term research and development program to begin to achieve our ultimate goal of eliminating the threat posed by strategic nuclear missiles.
One proposal that became a focus of the resulting Strategic Defense Initiative was a constellation of space-based lasers to destroy missiles in their boost phase. This led to the appellation “Star Wars.” Scientist-critics pointed out the enormous costs and vulnerabilities of such systems (Bethe et al. 1984Bethe, H., R. Garwin, K. Gottfried, and H.Kendall. 1984. “Space-Based Ballistic-Missile Defense.” Scientific American, October, 39–49.https://www.jstor.org/stable/pdf/24969454.pdf?refreqid=excelsior%3A7416c504611e2713cc7342371fa5aa43. [Google Scholar]).
The ABM Treaty included the limitation, however, that “Each Party undertakes not to develop, test, or deploy ABM systems or components which are sea-based, air-based, space-based, or mobile land-based.” The Reagan administration tried to redefine these limits so that R&D and testing of space-based systems could go forward. In 1987, however, the Democrats regained control of the Senate and Senator Sam Nunn, chairman of the Armed Services Committee, blocked this effort, warning President Reagan that “a unilateral executive branch decision to disregard” the interpretation of the ABM Treaty that had been provided when the Senate ratified the treaty “would provoke a constitutional crisis of profound dimensions” (Gordon 1987Gordon, M. 1987. “Reagan is Warned by Senator Nunn over ABM Treaty.” New York Times, February 7.https://www.nytimes.com/1987/02/07/us/reagan-is-warned-by-senator-nunn-over-abm-treaty.html [Google Scholar]).
The George H.W. Bush administration, which followed the Reagan administration, allowed funding for the Strategic Defense Initiative to decline, and that trend continued during the first two years of the Clinton administration. In 1994, however, the Republican Party captured control of both houses of Congress and began to push for a ballistic missile defense system that would cover the entire country. The Clinton administration eventually agreed to develop such a system for possible deployment.
In the meantime, Iraq used short-range, conventionally armed Scud missiles during the 1991 Gulf War, and Iran and North Korea also were developing ballistic missiles. The United States therefore developed an interest in “theater” ballistic missile defenses that would protect US military bases, as well as allies and ships, in the Middle East and East Asia. The Clinton administration began to negotiate with Russia about how to demarcate “theater” defenses from strategic defenses against intercontinental-range missiles.
In 1996, the Republican-led Congress established a Commission to Assess the Ballistic Missile Threat to the United States. The commission was led by Donald Rumsfeld, a former (Ford administration) and future (George W. Bush administration) secretary of defense. When the commission reported back in 1998, its conclusion was dramatic: If Iran and North Korea obtained clandestine assistance from Russian and Chinese experts, they could have ICBMs within as little as five years. As if to underline the report’s conclusion, North Korea attempted to launch a satellite into orbit a month after the report was published.
In 1997, US and Russian negotiators reached an agreement on first steps toward demarcating theater missile defense from strategic missile defense systems. Theater missile defense systems would be considered compliant with the ABM Treaty if their interceptors had a burnout velocity of less than 3 kilometers per second and were not tested against missiles with a maximum range greater than 3,500 kilometers. Regarding faster interceptors, the two sides could only agree that, if such interceptors were not tested against missiles with ranges greater than 3,500 kilometers, it would be up to the owning country to determine compliance with the ABM Treaty. Otherwise, the two countries committed to be transparent about their programs and to try to resolve concerns. The Republican majority was increasingly opposed to any limits on US ballistic missile defense, however, and forced the Clinton administration to commit that a demarcation agreement would be subject to Senate ratification. At the end of the Clinton administration, no demarcation agreement on theater missile defense had been submitted.
The fall
George W. Bush was elected president in November 2000 and nominated Rumsfeld to be his secretary of defense. On December 13, 2001, three months after the terrorist attacks of September 11, 2001, President Bush gave notice that the United States would withdraw from the ABM Treaty in six months. His explanation was that:
[T]errorists, and some of those who support them, seek the ability to deliver death and destruction to our doorstep via missile.
A year later, Bush announced that the first US Ground-based Missile Defense (GMD) interceptors for long-range ballistic missiles targeted against the United States would be operational at Fort Greely, Alaska in 2004, before the end of his first term. Rumsfeld observed that the system would be “better than nothing” (King 2002King, J. 2002. “Bush Rolls Out Missile Defense System.” cnn.com, December 18, 2002.http://edition.cnn.com/2002/US/12/17/bush.missile/index.html. [Google Scholar]).
The project to deploy ground-based interceptors, which the Obama administration continued, became an acquisitions disaster that violated all the Defense Department’s hard-learned rules about budget oversight and independent testing. There were no cost limits or performance requirements. The cumulative expenditures to date have been approximately $1 billion per deployed interceptor, about the same as their weight in gold. (Based on the facts that the Missile Defense Agency reports that each interceptor weigh 22.5 metric tons (million grams) each, Available at: www.ucsusa.org/sites/default/files/images/2016/07/GBI-component-details.jpg and over the past five years, the price of gold has averaged about $40/gram.) The intercept tests, despite being carefully choreographed by the developers for success, have failed about half the time (Missile Defense Agency 2018Missile Defense Agency. 2018. “Ballistic Missile Defense Intercept Test Record.” Fact Sheet, March.https://www.mda.mil/global/documents/pdf/testrecord.pdf. [Google Scholar]). Today, 44 interceptors are deployed: 40 at Fort Greely and four at the ICBM test site on Vandenberg Air Force Base in California.
In addition to the ground-based missile defense system, the United States also is deploying several types of theater missile defense systems, including Standard Missile 3 (SM-3) interceptor missiles on Aegis destroyers and cruisers as shown in Figure 3. The first two models, SM-3 Block 1A and Block IB, have burn-out velocities of about 3 kilometers per second – too slow to defend large areas of the United States.
None of these systems is immune to countermeasures that could be deployed by North Korea. A 1999 National Intelligence Estimate, which is still valid, concluded that (US National Intelligence Council 1999US National Intelligence Council. 1999. “Foreign Missile Developments and the Ballistic Missile Threat to the United States through 2015.” September.https://fas.org/irp/threat/missile/nie99msl.htm. [Google Scholar]):
Many countries, such as North Korea, Iran, and Iraq probably would rely initially on readily available technology—including separating [re-entry vehicles], spin-stabilized [re-entry vehicles], [re-entry vehicle] reorientation, radar absorbing material…, booster fragmentation, low-power jammers, and simple (balloon) decoys—to develop penetration aids and countermeasures… . These countries could develop countermeasures based on these technologies by the time they flight test their missiles.
Some of these countermeasures would be effective against the current US ballistic missile defense system, and the trove of potential countermeasures is so deep that the offense could easily continue to keep ahead of the defense (Sessler et al. 2000Sessler, A. M., J. M. Cornwall, B. Dietz, S.Fetter, S. Frankel, R. L. Garwin, K. Gottfried, et al. 2000. Countermeasures: A Technical Evaluation of the Operational Effectiveness of the Planned US National Missile Defense System. Union of Concerned Scientists and MIT Security Studies Program, Cambridge, Massachusetts. [Google Scholar]).
The future
It is striking that, 16 years after the George W. Bush administration took the country out of the ABM Treaty, the United States has not even deployed half the 100 strategic missile interceptors that the treaty allowed. Similarly, the SM-3 Block IA and IB missile interceptors currently deployed by the US Navy have burnout velocities near the 3-kilometer-per-second limit below which Russia and the United States agreed in 1997 theater missile defenses would not be able to provide national coverage against strategic missiles.
This relatively restrained US approach to deploying ballistic missile defense allowed Washington and Moscow to achieve significant cuts in their deployed strategic weapons even after the United States withdrew from the ABM treaty. The most recent agreement on reductions was the 2010 Strategic Arms Reduction Treaty (New START), which reduces strategic ballistic missile warheads on each side to about 1500.
The United States is now embarking on a much larger and faster expansion of strategic ballistic missile defense systems, however. The 2017 National Defense Authorization Act requires planning for expanding from 44 to a total of 104 GMD interceptors. Planned improvements to the GMD system include a new kill vehicle (the Redesigned Kill Vehicle), a new rocket booster, a new discrimination radar, and the development of multiple small kill vehicles for GMD boosters (Keller 2017Keller, J. 2017. “Raytheon and Lockheed Martin Refine MOKV Missile Defense to Kill Several Warheads with One Launch.” Military Aerospace Electronics, April 5.http://www.militaryaerospace.com/articles/2017/04/missile-defense-to-kill-several-warheads-at-once.html. [Google Scholar]).
More important, by 2020 the US Navy plans to begin deployment of a faster SM-3 Block IIA interceptor co-developed with Japan. It has a burnout speed of about 4.5 kilometers per second – 50 percent greater than the Block IA or Block IB. Also, its kill vehicle has “more than doubled seeker sensitivity” and “more than tripled divert capability” compared to the current SM-3 Block IB interceptor (Defense Department 2016Defense Department. 2016. “Fiscal Year (FY) 2017 President’s Budget Submission, Missile Defense Agency, RDT&E Vol. 21.” February, 2a–891.http://comptroller.defense.gov/Portals/45/Documents/defbudget/FY2017/budget_justification/pdfs/03_RDT_and_E/MDA_RDTE_MasterJustificationBook_Missile_Defense_Agency_PB_2017_1.pdf. [Google Scholar]). If deployed on a small number of offshore ships or at Aegis Ashore facilities, using the long-range GMD radars for determining approximate intercept points, Block IIA could cover the entire United States. According to Rondell Wilson, lead engineer for air and missile defense products at Raytheon (the manufacturer of the SM-3 Block IIA), “We can provide the SM-3 Block [II]A ashore as an under-layer capability for [ground-based interceptors]… . We can do that immediately (Drew and Dimascio 2017Drew, J., and J. Dimascio. 2017. “New Trajectory: As Pentagon Adds Dollars for Missile Defense, Raytheon Pitches SM-3s as ICBM Killers.” Aviation Week and Space Technology 179 (20): 58. [Google Scholar]).” Congress has recently mandated that, “if technologically feasible,” the Block IIA missile be tested against an ICBM-range missile (US House of Representatives 2017US House of Representatives. 2017. “National Defense Authorization Act for Fiscal Year 2018, Conference Report to Accompany H.R. 2810.” Report 115–404, November 9, Section 1680.https://www.gpo.gov/fdsys/pkg/CRPT-115hrpt404/pdf/CRPT-115hrpt404.pdf. [Google Scholar]).
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