Russia has long been concerned with U.S. ballistic missile defense programs, arguing that the increasing capabilities of U.S. missile defenses could undermine Russia's strategic offensive nuclear forces and undermine strategic stability. During the Strategic Arms Limitation Talks (SALT) in the 1970s, the United States and Soviet Union had addressed the link between offensive and defensive systems in their arms control treaty negotiations. However, in recent years, the United States has argued that the ballistic missile defense (BMD) programs it is pursuing will be neither numerous enough nor capable enough to intercept Russia's strategic offensive ballistic missiles or undermine Russia's strategic nuclear deterrent. The United States and Russia signed the New START Treaty—the Treaty ... on Measures for the Further Reduction and Limitation of Strategic Offensive Arms—on April 8, 2010, and it awaits Senate consideration. New START is not of unlimited duration; it would expire 10 years after it enters into force. When President Obama and President Medvedev launched the negotiations on this treaty in April 2009, they agreed that the two nations would address Russia's concerns with U.S. missile defense programs in a separate forum from the negotiations on a New START Treaty. However, during their meeting in Moscow in July 2009, they agreed that the new treaty would contain a "provision on the interrelationship of strategic offensive arms and strategic defensive arms." This statement, which appears in the preamble to New START, states that the parties recognize the existence of the interrelationship between strategic offensive arms and strategic defensive arms, that this interrelationship will become more important as strategic nuclear arms are reduced, and that current strategic defensive arms do not undermine the viability and effectiveness of the strategic offensive arms of the parties. Russia and the United States each issued unilateral statements when they signed New START that clarified their positions on the relationship between New START and missile defenses. Russia stated that the Treaty can operate and be viable only if the United States of America refrains from developing its missile defense capabilities quantitatively or qualitatively. Consequently, the exceptional circumstances referred to in Article 14 of the Treaty include increasing the capabilities of the United States of America's missile defense system in such a way that threatens the potential of the strategic nuclear forces of the Russian Federation. In its statement, the United States stated that its missile defense systems are not intended to affect the strategic balance with Russia. The United States missile defense systems would be employed to defend the United States against limited missile launches, and to defend its deployed forces, allies and partners against regional threats. The United States intends to continue improving and deploying its missile defense systems in order to defend itself against limited attack and as part of our collaborative approach to strengthening stability in key regions. Russia's Foreign Minister, Sergei Lavrov, indicated, in a press conference after the negotiators completed the treaty, that the language in the Treaty preamble was set down in a "legally binding" form. He stated, further, that the sides had appropriate levels of strategic offensive arms at this point, but "if there are changes to these levels, each side reserves the right to make a decision on whether to continue to take part in the process of strategic offensive arms cuts." Some in the United States have questioned whether this statement means that the United States and Russia agreed that increases in U.S. ballistic missile defenses would upset stability, and therefore that they could serve as cause to terminate the New START Treaty. Moreover, they have expressed concerns that, if the United States has not accepted this interpretation, the two parties hold different interpretations of their obligations under the Treaty and that these differences could disrupt the treaty's implementation. The Obama Administration has agreed that the language in the treaty preamble is "legally binding," in that it is a part of the formal text of the Treaty. But the Administration has insisted that the preamble contains no legal or practical limits on missile defense and imposes no obligations on the United States. Moreover, the Administration has insisted, as Under Secretary of State Ellen Tauscher stated, "Russia's unilateral statement on missile defenses is not an integral part of the New START Treaty. It's not legally binding. It won't constrain U.S. missile defense programs." Nevertheless, some have questioned whether Russia's threat to withdraw from New START might have a "chilling effect" on U.S. missile defense plans and programs. They contend that the United States might limit these programs itself to avoid a possible disruption of the arms control process or the possible increase in tensions with Russia. As Senator Jeff Sessions noted in a speech on May 13, 2010, "I can't help but worry that these provisions will have a negative impact on U.S. decision-making with respect to missile defense." Members of the Senate are likely to raise this question, and explore the potentially different U.S. and Russian views on the relationship between New START and U.S. ballistic missile defense programs, during the debate on the New START Treaty. When the United States and Soviet Union negotiated the 1991 START Treaty, the Soviet Union also sought to link limits on offensive nuclear weapons with limits on ballistic missile defenses. The United States did not agree to the Soviet proposals, so the Soviet Union released a unilateral statement when it signed START, noting that the Treaty would not remain in force if the United States withdrew from the 1972 ABM Treaty. This statement did not serve to slow U.S. missile defense programs after START entered into force. Moreover, the United States and Soviet Union held discussions during the latter half of the 1990s on possible modifications to the ABM Treaty so that the United States could deploy more extensive ballistic missile defenses without withdrawing from the Treaty. These negotiations proved unsuccessful. Russia continued to object to U.S. ballistic missile defense plans and to caution the United States not to withdraw from the Treaty. Nevertheless, when the United States withdrew from the ABM Treaty in 2002, Russia did not withdraw from START. This report seeks to shed some light on the past relationship between ballistic missile defenses and negotiations on offensive arms control treaties. It provides aN historical review of the way in which the United States and Soviet Union addressed ballistic missile defense issues during their negotiations on the first Strategic Arms Reduction Treaty (START) in the 1980s and early 1990s. It also provides a review of U.S. missile defense policy and summarizes data on missile defense spending during the 1980s, 1990s, and the past decade. The report then reviews the recent record on the way the New START negotiations addressed ballistic missile defense issues and offers some observations about whether this historical record may provide insights into how the United States might proceed with its ballistic missile defense programs in the future. Russia's concerns about U.S. missile defense programs derive from its stated concern that missile defenses could upset strategic stability by undermining the effectiveness of Russia's offensive nuclear weapons. Specifically, Russia appears to be concerned that, if the United States were to increase the numbers and capabilities of its missile defense interceptors while Russia was reducing its numbers of deployed offensive weapons, the time may come when the United States believed it had the ability to launch a first strike against Russia's strategic forces while protecting itself from Russia's retaliatory attack with its missile defenses. In this environment, Russia may believe it had to increase its offensive forces so that it would have enough surviving weapons to penetrate the U.S. missile defenses. Such a response could require a withdrawal from the New START Treaty. Many analysts argue that this "Cold War" view of the relationship between U.S. missile defenses and Russian offensive weapons should not be relevant in the current strategic environment, in which the United States and Russia are not poised on the brink of conflict. The Bush Administration emphasized this point when it noted, in the 2001 Nuclear Posture Review, that the United States would "no longer plan, size or sustain its nuclear forces as though Russia presented merely a smaller version of the threat posed by the former Soviet Union." This change in the U.S.-Russian relationship was also evident in U.S. ballistic missile defense plans that were intended to address concerns about emerging threats and adversaries. As a result, this Cold War offense-defense scenario is not consistent with the capabilities planned for U.S. missile defenses or the U.S. intent in deploying these systems. Specifically, the United States is pursuing missile defenses to defend its allies and forces overseas against threats from shorter and medium-range missiles that they might encounter in regional conflicts around the world, and to defend the continental United States from threats that might emerge as nations deploy small numbers of long-range ballistic missiles. Thus, although the United States may eventually be able to defend against a force of dozens of long-range missiles from an emerging adversary, it would not have the ability to defend against an attack with hundreds of Russian missiles. This model of strategic stability was, however, relevant to assessments of the relationship between offensive and defense weapons during the Cold War. It is seen to have had a significant effect on the way that arms control agreements negotiated in the 1970s and 1980s addressed missile defenses and offensive reductions. In theory, strategic stability refers to the condition that exists when two potential adversaries recognize that neither would gain an advantage if it were to begin a conflict with the other. Each party would recognize not only that the costs of the conflict, even if it launched the first strike, would outweigh the gains that might be realized, but also that the other side was likely to draw the same conclusion. Each would know that, even if it were attacked, enough of its forces could survive the first strike to retaliate against the other side with a devastating response. And each would know that, even if it did attack first, the other side would have enough forces surviving the strike to launch a devastating retaliatory attack. Hence, neither would feel compelled to shoot first, because the costs of doing so would far outweigh the benefits. This situation, where each side is equally vulnerable to retaliation from the other, is considered to be stable. This model of strategic stability postulates a strong relationship between offensive forces and defensive forces. It assumes that each side has enough offensive forces to retaliate after a first strike and it assumes that neither side has the defensive capability to impede the other sides' ability to deliver its devastating retaliatory strike. If missile defense systems were built to defend against an attack on strategic nuclear offensive forces, so that they protected those forces against a first strike and ensured that each side had enough weapons to launch a devastating retaliatory attack, then missile defenses could contribute to stability. Similarly, if the missile defenses were limited in number and scope, so that a nation knew it could penetrate the defenses in a retaliatory strike, then they would not upset strategic stability. If, however, one side were to deploy defenses that could protect its territory, broad segments of its infrastructure, its leadership, or its population, then the other may conclude that it needed to increase its offensive forces to make sure they could penetrate those defenses and cause a sufficient level of destruction in a retaliatory attack. Alternatively, if each side limited its defensive forces, both sides could reduce their offensive forces because they would be certain that the surviving weapons could penetrate to their targets in a retaliatory strike. The model of strategic stability that linked reductions in offensive weapons with limits on ballistic missile defenses was enshrined in the arms control process of the 1970s. In the 1972 Treaty ... on The Limitation of Anti-Ballistic Missile Systems (ABM Treaty), the United States and Soviet Union agreed that they would not deploy defenses that could protect their entire territories, and would, instead, deploy only a single limited system that could protect either the nation's capital or an ICBM deployment area. The companion Interim Agreement on Certain Measures With Respect to the Limitation of Strategic Offensive Arms sought to freeze numbers of missiles in each side's offensive forces, while the 1979 SALT Treaty called for more detailed limits and some reductions on strategic offensive forces. This Treaty never entered into force, and the advent of ballistic missiles with multiple warheads (MIRVs) undermined efforts to limit offensive forces by limiting the number of delivery vehicles. As a result, in subsequent years, the United States and Soviet Union both increased the numbers of warheads on their offensive forces, in spite of the agreed limits on ballistic missile defenses. Nevertheless, many analysts continued to assert that reductions in offensive forces and limits on ballistic missile defenses could work together to enhance strategic stability. The offense/defense relationship enshrined in the ABM and SALT Treaties was not the only model of strategic stability discussed during the START negotiations and the U.S. debates over missile defense in the 1980s. Some analysts postulated that missile defense capabilities could enhance stability and encourage further reductions in offensive weapons if the defenses were robust enough to stop nearly all of an adversary's missiles in a first strike. In this model, strategic stability would exist if both potential adversaries knew that they were not at risk from a surprise first strike because each knew that it could stop the attack with its missile defense systems. And both knew that the other side would not be tempted to launch a first strike because it knew its attack would be unsuccessful. In this environment, both sides should be willing to reduce their strategic offensive forces because they would no longer need an assured retaliatory capability. Further, reductions in the offensive forces on both sides would enhance the effectiveness of the missile defenses. President Ronald Reagan embraced this model of strategic stability and the offense/defense relationship with his 1983 proposal for the Strategic Defense Initiative (SDI). He envisioned SDI as a robust, global system that would protect the United States from a massive launch of Soviet missiles. He also offered to share such a system with the Soviet Union, possibly recognizing that unilateral defenses could be destabilizing because they would protect only one potential adversary from a first strike. Missile defenses would only strengthen strategic stability if both sides were protected from a first strike, so that they provided "mutual assured survivability" for both potential adversaries. On March 12, 1985, the United States and the Soviet Union began negotiations in Geneva, referred to as the Nuclear and Space Talks (NST). These negotiations addressed defense and space systems, intermediate-range nuclear forces (INF), and strategic nuclear weapons with three separate negotiating teams. The competing views on strategic stability and the offense/defense relationship were evident in these negotiations and affected both the substance of the proposals presented by the United States and Soviet Union and the structure of the arms control negotiations. The United States and Soviet Union both linked their proposals for reductions in strategic offensive forces to the broader goal of the eventual elimination of nuclear weapons. However, the United States and the Soviet Union had different versions of a transition to a world without nuclear weapons. Specifically, because of their different views on stability and the offense/defense relationship, they differed on the role that missile defenses would play in the arms reduction process. President Reagan based his position on a "New Strategic Concept," which was first detailed by Ambassador Paul Nitze, the senior arms control adviser to the Administration, on January 25,1985, just prior to the first round of the Geneva negotiations. The U.S. position outlined three phases. First, the United States sought a radical reduction in the number and power of all nuclear weapons. Second, there would be a transition period away from reliance on nuclear weapons after a decision was made that effective and survivable strategic defenses against ballistic missiles could and should be deployed. After the deployment of robust missile defenses, this transition period could be followed by the eventual elimination of all nuclear weapons. President Gorbachev's version of a nuclear-free world, which he unveiled in January 1986, also foresaw three distinct phases. First, by the early 1990s, the superpowers would reduce by half the number of their strategic nuclear weapons and dismantle all their INF weapons based in Europe. In the second phase, all nuclear weapons powers would begin to dismantle all their nuclear weapons and join in a nuclear test ban. In the third phase all nuclear weapons would be dismantled by the year 2000. For President Gorbachev, these three phases would only be possible if the United States and Soviet Union remained committed to the ABM Treaty and the United States abandoned its plans to deploy robust missile defenses. Although both versions anticipated complete nuclear disarmament through a series of phases, there were fundamental differences. The Reagan vision implied that each phase was dependent upon developing SDI, and that deployment of strategic defenses was necessary as an "insurance policy" in a world without nuclear weapons. In contrast, the Gorbachev vision argued that halting SDI was a prerequisite to disarmament because the U.S. search for comprehensive strategic defenses was inherently destabilizing, threatening to give the United States a "first strike potential" against the Soviet Union. These differences were evident in the U.S. and Soviet negotiating positions in the Defense and Space Talks. At the Reykjavík summit where President Reagan indicated that the United States would agree to a 10-year commitment not to withdraw from the ABM Treaty if the Soviets agreed to (l) to reduce strategic offensive weapons by 50% in five years (changed to seven years in April 1987); (2) eliminate all ballistic missiles in a second five-year period; and (3) allow deployment of strategic defenses after a 10-year period (changed to seven years in April 1987). In other words, the United States offered to delay the deployment of SDI for 10 years while the United States and Soviet Union implemented deep reductions in their offensive forces. President Gorbachev agreed, at the Reykjavík Summit, that the United States and Soviet Union should reduce their offensive nuclear weapons by 50% within five years. He also agreed that both sides should eliminate their offensive nuclear forces within 10 years, although there were differences in the details of the U.S. and Soviet positions on this issue. However, President Gorbachev insisted on linking this time line for offensive reductions to resolution of the fundamental U.S. and Soviet differences over the SDI program. President Gorbachev agreed with the U.S. proposal that the parties should remain committed to the ABM Treaty for a period of 10 years. But he sought to slow or stall research on SDI during that period, proposing that all research and testing of strategic defense technologies would be restricted to the laboratory. He also differed from President Reagan, who had proposed that the United States could make a unilateral decision to withdraw from the ABM Treaty and deploy SDI at the end of the 10-year period, and indicated that the parties would have to agree on a way forward for the ABM Treaty and SDI at the end of the 10-year period. In the end, the United States and Soviet Union left Reykjavík without reaching an agreement on either offensive reductions or the way forward for missile defenses and the ABM Treaty. Press reports indicate that Presidents Reagan and Gorbachev were in general agreement on the goals of reducing, and eventually eliminating offensive forces, and on the goals of abiding by the ABM Treaty for 10 years and restricting missile defense deployments during that time. However, according to most reports, President Gorbachev insisted on linking these agreements to an agreement that would restrict SDI to research in the laboratory, and President Reagan was unwilling to accept such strict limits on missile defense research, even in pursuit of the elimination of offensive nuclear weapons. The United States saw the three sets of discussions in the Nuclear and Space Talks as independent of each other. In September 1984, President Reagan noted that "if progress is temporarily halted at one set of talks, this newly established framework could help us take up the slack at other negotiations." In contrast, Soviet negotiators stressed that the interrelationship of the talks meant that there had to be progress in all three areas at the same time. By 1987, the Soviet Union had agreed to pursue the negotiations on the INF Treaty separately, but it continued to link progress on reductions in strategic offensive forces with progress in the defense and space talks. In January 1988 the Soviet negotiators submitted a draft protocol on Defense and Space to their draft START Treaty, linking agreement on strategic arms reductions to resolution of the U.S.-Soviet differences over space and defensive systems. Not only did it contain the Soviet proposal for a 10-year ban on SDI deployment and a mutual agreement on how to proceed at the end of the 10-year period, it maintained that the START Treaty would cease to be in force if either party violated or abrogated the ABM Treaty or the Protocol. Hence, in the Soviet framework, a U.S. decision to deploy SDI without Soviet agreement would have breached the Defense and Space Protocol and terminated Soviet compliance with START. The United States, in contrast, submitted two completely separate documents for the negotiations—a draft treaty on defense and space weapons and a draft treaty on strategic offensive arms reductions. It rejected any link between the two and any suggestions that compliance with the ABM Treaty would affect the status of the START Treaty. The Soviet Union eventually agreed that the two documents could be separate, but continued to insist that progress in offensive arms reductions had to be linked to progress on missile defenses. The Soviet Union insisted it would only accept a 50% reduction in offensive forces if the two sides concluded a Defense and Space agreement that would restrict research, development, and testing of missile defense systems. In September 1989, during a ministerial meeting between Secretary of State James Baker and Soviet Foreign Minister Shevardnadze, the Soviet Union dropped its link between the conclusion of START and the conclusion of an agreement on Defense and Space Weapons. It continued to state that it would withdraw from START, however, if the United States violated the ABM Treaty, and it sought to include an agreed statement in START that recognized this linkage. The United States refused, and in February 1990, the Soviet Union withdrew its insistence on an agreed statement outlining its right to withdraw from START. Instead, when the United States and Soviet Union signed START in July 1991, the Soviet Union issued a unilateral statement that indicated that it would withdraw from START if the United States withdrew from the ABM Treaty. Specifically, the Soviet letter stated: This Treaty may be effective and viable only under conditions of compliance with the Treaty between the U.S. and the USSR on the Limitation of Anti-Ballistic Missile Systems, as signed on May 26, 1972. The extraordinary events referred to in Article XV of this Treaty also include events related to withdrawal by one of the Parties from the Treaty on the Limitation of Anti-Ballistic Missile Systems, or related to its material breach. Article XV states that "each Party shall, in exercising its national sovereignty, have the right to withdraw from this Treaty if it decides that extraordinary events related to the subject matter of this Treaty have jeopardized its supreme interests." The United States did not agree with the Soviet view and noted, in its own unilateral statement: the full exercise by the United States of its legal rights under the ABM Treaty, as we have discussed with the Soviet Union in the past, would not constitute a basis for such withdrawal. The United States will be signing the START Treaty and submitting it to the United States Senate for advice and consent to ratification with this view. In addition, the provisions for withdrawal from the START Treaty based on supreme national interests clearly envision that such withdrawal could only be justified by extraordinary events that have jeopardized a Party's supreme interest. Soviet statements that a future, hypothetical U.S. withdrawal from the ABM Treaty could create such conditions are without legal or military foundation. The ABM Treaty, as signed on May 26, 1972, has already been substantially amended and clarified by subsequent agreements between the Parties. Moreover, current and future negotiations, to which the Soviet Union committed in the June 1990 Summit Joint Statement, could lead to significant additional changes in the ABM Treaty, or its replacement. Changes in the ABM Treaty agreed to by the Parties would not be a basis for questioning the effectiveness or viability of the Treaty on the Reduction and Limitation of Strategic Offensive Arms. The United States signed START even though the Soviet Union continued to assert that further development of U.S. missile defenses would constitute a threat to its security and even though the Soviet Union asserted a right to withdraw from START if the United States withdrew from the ABM Treaty to deploy those defenses. The United States rejected this linkage, and, through its own statement, noted that the two nations were still negotiating possible changes to or a replacement for the ABM Treaty in the Defense and Space Talks. The Senate Foreign Relations Committee held hearings on the START Treaty during the first half of 1992. During these hearings, neither the witnesses from the George H.W. Bush Administration nor the Senators on the committee mentioned the Soviet unilateral statement linking START and the ABM Treaty or the U.S. response to that statement. The Senators were concerned, however, about the possibility that a recent agreement between President George H.W. Bush and President Yeltsin to pursue far deeper reductions in offensive weapons (an agreement that would become START II) would be impossible if the United States withdrew from the ABM Treaty. James Baker, who was Secretary of State, had indicated that he did believe that U.S. withdrawal from the ABM Treaty would derail the negotiations on deeper reductions. Two START negotiators—Linton Brooks and Ron Lehman—agreed with the Secretary's views. Hence, even though the administration witnesses acknowledged that Russia might link further negotiations on deeper reductions to U.S. compliance with the ABM Treaty, no one questioned whether Russia might withdraw from START under those circumstances. The Soviet effort to link START and the ABM Treaty had escaped everyone's notice. During the 1980s, the Soviet Union expressed strong and continuing objections to U.S. missile defense goals, in general, and the SDI program, in particular, and placed a high priority on limiting these programs through arms control. But, as the negotiations proceeded, the Soviet Union backed away from these demands so that it could preserve progress in limits on offensive weapons. It began by insisting that an agreement limiting missile defense research and deployments be crafted as a Protocol to the treaty limiting offensive nuclear weapons. When the United States refused to accept this formula, the Soviet Union agreed to address defensive forces and offensive forces in two separate treaties, but continued to try to link the two with an agreed statement in START. Again, the United States refused, and eventually the Soviet Union had to settle for a unilateral statement expressing its own view of the relationship between START and the ABM Treaty. In the end, in spite of its constant criticism of the SDI program, it placed a higher priority on the completion of a treaty limiting strategic offensive arms than it did on establishing legally binding limits on U.S. missile defenses and a legally binding link between U.S. compliance with the ABM Treaty and START. The United States, for its part, demonstrated throughout the START talks that it placed a higher priority on protecting its missile defense programs than it did on completing a treaty limiting offensive weapons by resisting all Soviet efforts to link the two in the negotiations. Moreover, this ordering of priorities remained evident throughout the 1990s. U.S. missile defense programs expanded and accelerated during the 1990s. Although the United States and Russia participated in discussions on how to fit these programs into the ABM Treaty framework, the United States would not accept any outcome in these talks that restricted its options on national missile defenses. Russia continued to object to U.S. missile defense plans through the 1990s. It continued to insist that the ABM Treaty was the cornerstone of strategic stability. Yet, when the United States withdrew from the ABM Treaty in 2002, Russia did not withdraw from START or even mention that it had once linked the two treaties. Russia did withdraw from the START II Treaty, but this was a symbolic gesture as START II had never entered into force and neither the United States nor Russia were implementing its reductions. Moreover, Russia continued to participate in negotiations with the United States on the Strategic Offensive Reductions Treaty, and agreed, through that treaty, to further reduce its strategic offensive weapons, even though it knew that the United States would be deploying more extensive ballistic missile defenses. The same pattern of priorities, for both the United States and Russia, is evident in the negotiations on the New START Treaty. Throughout the negotiations, Russian officials asserted that Russia would not accept further reductions on offensive forces unless the United States addressed Russian concerns about its planned missile defense programs. For example, in December 2009, Russia's Prime Minister, Vladimir Putin, stated that the U.S. plan to build a missile defense system threatened the Cold War-era balance of power. He stated that, if the United States had missile defenses and Russia did not, then "the balance will be disrupted and then they will do whatever they want and aggressiveness will immediately arise both in real politics and economics." He noted that, to restore the balance, Russia would have to deploy greater numbers of offensive weapons, so that it would have the means to overwhelm a U.S. missile defense system. Press reports indicate that missile defense remained an issue in the negotiations during February 2010. Specifically, Russia continued to insist that U.S. missile defense interceptors located near Russian territory could undermine its strategic nuclear deterrent, though the United States insisted the interceptors would not have the capability to intercept long-range missiles. The United States, in a statement released by the State Department in December 2009, repeated that reductions in offensive weapons and missile defenses were two separate issues and that discussions on the two would continue separately. And, during the final months of the negotiations, the United States continued to resist Russian attempts to link the two. Press reports indicate that, at one point, President Obama was so exasperated with the Russian position that he was willing to walk away from the negotiations. The United States held to its original position that the treaty would not include any limits on missile defenses. Russia, however, as it did in the original START negotiations, backed away from its insistence on legally binding limits on missile defenses and settled for a unilateral statement that outlined its concerns. According to press reports, it did so when political leaders in Moscow refused to accept the Russian military's insistence on missile defense limits in the interest of concluding an agreement to limit U.S. offensive forces. As it had in the original START negotiations, the United States appears to have placed a higher priority on protecting its BMD programs than on reaching an agreement on limits on offensive nuclear weapons. And Russia, in spite of its ongoing concerns with U.S. missile defense programs, appears to have placed a higher priority on completing the treaty limiting offensive nuclear weapons than on imposing limits on U.S. BMD systems. On entering office, the Reagan Administration increased funding for ballistic missile defenses (BMD) against long-range strategic ballistic missiles; this funding had been growing since the Carter Administration. In March 1983, President Reagan announced an expansive, new effort to develop non-nuclear BMD that would seek to protect the United States against a full-scale Soviet nuclear strike as a means of moving toward the abolition of nuclear weapons altogether. Although the SDI remained a research and development effort, with few plans for intercept tests or actual deployment schedules, Reagan and his supporters envisioned a global BMD capability with thousands of land-, sea-, air-, and space-based sensors and interceptors. The stated goal was to replace nuclear deterrence with defenses. As cost estimates and technical challenges mounted, the Reagan Administration scaled back its objectives for SDI. In 1987, the Reagan Administration announced a "Phase 1" deployment of land- and space-based sensors and interceptors that would not offer complete protection against a full-scale Soviet nuclear attack, but would, instead, seek to disrupt such an attack so significantly as to call into question the attack's effectiveness. It was argued at the time by its supporters that Phase 1 would enhance nuclear deterrence while the United States continued its efforts to replace deterrence with ballistic missile defenses. Congress gave some support to conducting BMD research and development, but was broadly opposed to any significant BMD deployments that might increase risks to strategic stability between the United States and the Soviet Union. Although the executive branch did not promote tactical or theater BMD efforts, Congress advocated and provided funding for such programs. The Reagan Administration and its BMD supporters recognized that many of the technologies being pursued in the SDI program would not be allowed by the ABM Treaty when they entered the testing or deployment phases. Therefore, the Reagan Administration sought a new interpretation of the ABM Treaty that it hoped would allow for the testing of space-based and exotic BMD technologies, such as lasers. Many in Congress at the time objected to this reinterpretation of the ABM Treaty, with Senator Nunn mounting a particularly comprehensive defense of the traditional interpretation of the ABM Treaty, a view the Senate supported despite strong objections by some. In general, Congress tendered strong support for the ABM Treaty during this era and was not supportive of BMD programs that might lead to violating the Treaty, which was largely viewed as a vital component of U.S.-Soviet strategic stability. It was during this time, as mentioned earlier, that the Reagan Administration opened new negotiations with the Soviets to reach agreement on modifying or replacing the ABM Treaty through the Defense and Space Talks. President George H.W. Bush responded to the spiraling costs and technical challenges of Phase I and the changed international political environment after the fall of the Soviet empire with a further contraction of the goals for missile defense. Instead of seeking to protect the United States against a large-scale attack, the United States would seek to deploy a defensive system that would provide Global Protection Against Limited Strikes (GPALS), arguably a more modest version of Phase 1. This new focus recognized that the demise of the Soviet Union had reduced the likelihood of a large-scale nuclear strike, but also had increased the chance of a small accidental or unauthorized attack. GPALS would also seek to protect the United States, friends and allies, and troops deployed abroad against attacks from missiles fired from other nations. The George H.W. Bush Administration envisioned a GPALS system that would have included up to 1,000 land-based interceptors and perhaps another 1,000 space-based interceptors and space-based sensors. The Administration recognized this system would not be permitted under the terms of the ABM Treaty and later held negotiations with the Russian government to identify a more cooperative and flexible regime to replace the ABM Treaty. Again, although Congress was not supportive of BMD programs that would threaten the ABM Treaty, which most believed inherently contributed to strategic stability, some in Congress, such as Senator Nunn, continued to argue for the deployment of a much more modest ABM Treaty compliant BMD to protect against limited or accidental attacks. In the aftermath of Desert Storm, Congress also approved the Missile Defense Act of 1991 ( P.L. 102-190 , National Defense Authorization Act for FY1992-1993) and stated it is a goal of the United States to deploy an anti-ballistic missile system, including one or an adequate additional number of anti-ballistic missile sites and space-based sensors, capable of providing a highly effective defense of the United States against limited attacks of ballistic missiles; maintain strategic stability; and provide highly effective theater missile defenses (TMD) to United States forward-deployed and expeditionary armed forces and to U.S. friends and allies. The Clinton Administration suspended negotiations begun under the previous Bush Administration to discuss possible changes to the ABM Treaty and scaled back significantly efforts to develop and deploy a national BMD capability. The 1993 Bottom-up Review (BUR), a major Department of Defense- (DOD-) wide review of U.S. military plans and programs, concluded that the United States should not proceed with the deployment of a national missile defense because there was no military requirement for such a system. Instead, the Clinton Administration decided to emphasize, to an even greater extent, efforts begun after Desert Storm to develop BMD capabilities against short-range ballistic missiles. Defense Secretary Aspin noted at the time that these program changes reflected an assessment that the regional ballistic missile threat to U.S. troops abroad, and to its friends and allies, already existed, and that a long-range ballistic threat to the United States per se might emerge only in the future. DOD therefore cut significantly its budget for national missile defense, increased significantly theater BMD funding, and indicated that all BMD programs would be pursued in compliance with the ABM Treaty. Later, the Missile Defense Act of 1995 (in P.L. 104-106 , National Defense Authorization Act for Fiscal Year 1996) declared it the policy of the United States to develop as soon as possible affordable and operationally effective theater missile defenses; develop for deployment a multiple-site national missile defense system that is affordable and operationally effective against limited, accidental and unauthorized ballistic missile attacks on the United States, and which can be augmented over time as the threat changes to provide a layered defense against limited, accidental or unauthorized ballistic missile threats; initiate negotiations with Russia as necessary to provide for the national defense systems envisioned by the act; and consider, if those negotiations fail, the option of withdrawing from the ABM Treaty. At the time, the intelligence community estimated that there was not likely to be a long-range ballistic threat to the United States for at least the next 10-15 years. In particular, the 1995 National Intelligence Estimate (NIE) supported this view. On that basis, in 1996, the Clinton Administration adjusted its BMD efforts and adopted a new strategy for long-range or national missile defense (NMD). This 3+3 strategy would guide NMD development and potential deployment. Under this strategy, the United States would develop an NMD system to defend the United States against attacks from small numbers of long-range ballistic missiles launched by hostile nations, or, perhaps, from an accidental or unauthorized launch of Russian or Chinese missiles. The strategy envisioned continued development of NMD technologies during the first three years (1997-2000), followed by a deployment decision (in 2000), if the system was technologically feasible and warranted by prospective threats. If a decision to deploy a NMD system was made, the plan then was to deploy that system within the second three-year period (2000-2003). Development and deployment was to be conducted within the limits of the ABM Treaty. This approach was later modified to allow a longer lead time for possible deployment (possibly by 2005), and according to the Pentagon at the time, to reduce the amount of program risk. Many in Congress, however, took issue with the 1995 NIE about long-range threats from rogue states and determined that the proposed funding for TMD and especially NMD during this time was not adequate and therefore increased it significantly in FY1997 and FY1998. Congress also passed legislation ( P.L. 104-201 ) establishing the Commission to Assess the Ballistic Missile Threat to the United States (the 1998 Rumsfeld Commission Report), which concluded that the threat to the United States posed by emerging rogue nation ballistic missile programs was broader, more mature, and evolving more rapidly than predicted by estimates from the intelligence community. The subsequent 1998 flight test of a long-range North Korean ballistic missile strengthened the view that a strong BMD effort was needed against countries such as North Korea, Iraq, and Iran. During this time, Congress passed the National Missile Defense Act of 1999 ( P.L. 106-38 ), which declared it U.S. policy to deploy as soon as technologically possible a National Missile Defense (NMD) system capable of defending U.S. territory against limited ballistic missile attack (whether accidental, unauthorized, or deliberate), with funding subject to the annual authorization of appropriations and the annual appropriations of funds for NMD; and seek continued reductions in Russian nuclear forces. The Minority in the Senate Armed Services Committee took issue with this act on grounds that it would "needlessly make a NMD decision now, before the Defense Department wants to, needs to, or is prepared to make such a decision." Furthermore, they argued, the act would undermine the current effort of the Administration to reach a negotiated agreement on any changes to the ABM Treaty that may be necessary to accommodate deployment of a limited NMD system. We cannot and will not give Russia or any other nation a veto over our NMD requirements or programs. But making a decision to deploy an NMD system before we attempt to negotiate changes to the ABM Treaty—and before DoD says the nation can responsibly make such a decision—could reduce Russia's willingness to work with us on reducing nuclear weapons under the START process, lead Russia to retain thousands of nuclear warheads it would otherwise eliminate, and dramatically increase the threat of nuclear proliferation. It should be noted, however, that the act did not adversely affect U.S. efforts to discuss possible changes to the ABM Treaty, nor did the act appear to adversely affect U.S.-Russian relations on START. Ultimately, however, in September 2000, President Clinton decided not to authorize deployment of a national missile defense system at that time. He stated that he could not conclude "that we have enough confidence in the technology, and the operational effectiveness of the entire NMD system, to move forward to deployment." Throughout the 1990s, questions again were raised over the technical limitations of many BMD programs, especially against long-range ballistic missiles. President George W. Bush entered office prepared to advance BMD deployment as a key national security objective. The Bush Administration substantially increased funding for BMD programs and laid the foundation for withdrawal from the ABM Treaty, which formally occurred in June 2002. The Bush Administration's argument for abrogating the ABM Treaty centered around a different strategic environment from 1972 when the Treaty was signed: Soviet forces no longer threatened the United States and the greater threat came from the proliferation of ballistic missiles and weapons of mass destruction from other countries. Special concern was focused on rogue states and terrorism in the wake of 9/11. The Russian government offered little opposition to the Administration's decision to withdraw from the Treaty, and potential allied criticism in Europe was notably muted. Also in 2002, President Bush announced his decision to deploy a limited NMD system against long-range missiles by the fall of 2004. Although this goal was met with the initial deployment of five ground-based interceptors in silos in Alaska by December 2004, criticism of the system's operational capability focused on testing and other technology problems. Some argued at the time and those arguments continue through today that the test results of the system deployed in Alaska and California do not support Pentagon assessments that the system is operationally effective. The Bush Administration continued to emphasize land- and sea-based BMD against short-range ballistic missile threats and also sought to deploy an additional long-range BMD capability in Europe, which effort ultimately stalled largely because of delays in the ratification of agreements between the United States and Poland and the Czech Republic. The practical effect of the decision to abrogate the ABM Treaty has been to allow the increasing integration of multiple systems into a global U.S. BMD capability, restricted only by funding and technology. During the 2000s, significant progress was made in terms of integrating all the various land-, sea-, air-, and space-based BMD sensor capabilities, with the diverse assortment of short-, medium- and long-range BMD interceptor systems deployed by the U.S. military around the globe. The degree to which all these systems are now integrated has, in the views of many, significantly increased the BMD potential of the U.S. military. That BMD capability is now also widely viewed as a critical element of U.S. military strategy. The Obama Administration is continuing to evolve an integrated, global U.S. BMD capability to counter ballistic missile threats from countries such as Iran and North Korea. In September 2009, the Obama Administration canceled the central element of the George W. Bush plan to deploy long-range interceptors in Poland and a large radar facility in the Czech Republic. Instead, the Obama Administration gave priority to expanding some BMD elements and accelerating others that were already underway in response to new assessments of Iranian ballistic missile capabilities. Defense Secretary Gates announced that this regional BMD capability, known as the Phased Adaptive Approach (PAA), could be surged on relatively short notice during crises or as the situation might demand. The PAA would be based primarily on existing BMD sensors and Patriot, THAAD, and Aegis BMD interceptors. Secretary Gates argued the PAA would be more responsive and adaptable to the direction and pace of Iranian short- and medium-range ballistic missile proliferation. The Administration says that this capability will continue to evolve and expand over the next decade to include BMD against intermediate- and long-range Iranian missiles. Beyond 2020, it is envisioned that new BMD capabilities being considered against Iranian ICBMs will be developed and deployed in Europe, which may well present problems for Russia and challenges for U.S.-Russian strategic relations if those planned BMD capabilities are achieved. In addition, the Pentagon's BMD Review (February 2010) outlined a number of priorities designed to shape BMD policy and programs. Many might argue these priorities have broad political and military support today that demonstrate the nation's strong commitment to BMD: the United States will continue to defend the homeland against the threat of limited ballistic missile attack; the United States will defend against regional missile threats to U.S. forces, while protecting allies and partners and enabling them to defend themselves; before new capabilities are deployed, they must undergo testing that enables assessment under realistic conditions; the commitment to new capabilities must be fiscally sustainable over the long term; U.S. BMD capabilities must be flexible enough to adapt as threats change; and the United States will seek to lead expanded international efforts for missile defense. Looking back at the evolution of U.S. BMD efforts since President Reagan's speech in March 1983, several key observations can be made. First, U.S. decision makers in the executive branch and in Congress have sought to balance competing strategic priorities—developing and deploying BMD capabilities while seeking to preserve a stable U.S.-Soviet/Russian strategic nuclear relationship. In the 1980s, the Reagan Administration offered a vision of transitioning away from reliance on strategic nuclear weapons by seeking to deploy widespread global BMD capabilities that would then allow significant nuclear reductions or even abolition of nuclear weapons. The Soviet vision was the reverse, suggesting significantly deep reductions of offensive nuclear weapons was the prerequisite to global BMD. At the time, Congress played the role of dampening efforts to expand BMD beyond that permitted by the ABM Treaty, which was widely viewed at the time as representing the foundation of the U.S.-Soviet strategic nuclear relationship. Figure 1 shows the evolution or funding of the U.S. BMD program during this time, from President Reagan's SDI program to when President George W. Bush announced U.S. withdrawal from the ABM Treaty. Figure 1 shows a number of things. First, that after initial executive branch reluctance to advance TMD, which was not ABM Treaty constrained, funding for some TMD was provided by Congress and then increased significantly after Desert Storm with Pentagon and congressional support. Although the initial focus was on Soviet short-range ballistic missiles that might threaten NATO Europe, TMD became seen as a viable option for countering the growing proliferation of short-range missiles around the world. Figure 1 also reflects the fact that funding support for NMD efforts was then bound by what most believed the ABM Treaty permitted; the policy and funding debates were heavily influenced by efforts to pursue BMD programs in compliance with the ABM Treaty. Although the Reagan, George H.W. Bush, and Clinton Administrations each had plans for NMD that at some point would not have been permitted under the ABM Treaty, Congress in general held BMD programs accountable to the Treaty as each of those administrations at the same time sought in various ways to negotiate different changes to the ABM Treaty or seek its replacement. Some might argue that funding support for NMD fell after START was signed, but the initial program reductions were due to two major factors: (1) there was a predisposition on the part of incoming Defense Secretary Les Aspin to find a "peace dividend" in the DOD budget after the fall of the Soviet Empire, and (2) the Bottom-up Review concluded that long-range missile threat assessments allowed for a much reduced NMD effort. Secretary Aspin made no reference to START or offensive arms control issues when proposing these changes. Congress, however, disagreed with the long-range ballistic missile threat assessment from rogue states such as Iraq, Iran, and North Korea and then significantly increased NMD budgets not long after START I entered into force. In fact, BMD and NMD budgets, more specifically, rose steadily throughout most of the START 1 era. Figure 2 shows the evolution of DOD-wide BMD funding support since President Reagan to date. After initial growth under Reagan, top-line BMD budgets stabilized under George H.W. Bush, and declined under Clinton before rising steadily since the mid-1990s. Some would argue that cuts to the President's Budget (PB) for BMD in the 1980s and early 1990s were due, in no small part, to Congress placing some bounds on programs that might destabilize the U.S.-Soviet strategic nuclear relationship and undermine the ABM Treaty. BMD funding requests in the early 1990s under Clinton may have reflected an interest in pursuing BMD programs in compliance with the ABM Treaty. Some would argue that reductions in funding and changes in program goals were due to other factors, notably U.S. adjustments to the end of the Cold War. A focus on ballistic missile proliferation outside Russia may have played an important role in the direction of BMD from the mid-1990s on. After significant congressional BMD funding increases for NMD in the mid-to-late 1990s, an argument can be made that differences between executive branch and congressional interests in BMD began to narrow, and more so significantly after 9/11 and withdrawal from the ABM Treaty. Figure 3 illustrates this last point more sharply—that BMD funding for some time now has had broad support, seemingly regardless of which political party controls the White House, Senate, or House of Representatives. The notable exception was in the mid-1990s when Congress increased BMD budgets significantly over Clinton Administration requests. Broad support for BMD seems more pronounced since the decision to withdraw from the ABM Treaty, which has allowed BMD to proceed bounded now only by technology and funding availability. As a practical matter, over the past decade, all U.S. BMD sensor and interceptor capabilities have become increasingly integrated as part of an overall global BMD system, which the U.S. military argues is essential to U.S. national security interests. The Obama Administration's long-range plan to counter Iranian ICBMs later in the decade may present national security challenges at that time. Currently, the Obama plan is to deploy regional ICBM capable interceptors in Europe beginning after 2020, if an Iranian ICBM threat develops. Such a regional ICBM deployment might not be well received by Russia, which has demonstrated a history of critical opposition to U.S. plans that could affect its own strategic nuclear retaliatory forces. But, by the time U.S. missile defense capabilities reach this juncture, the New START Treaty would be close to the end of its 10-year term. The historical review presented in this report suggests that the United States did not restrain its ballistic missile defense programs or reduce its expenditures on ballistic missile defenses in an effort to ensure that Russia remained committed to the original START Treaty. To the contrary, U.S. spending on ballistic missile defense programs increased during the 1990s; the U.S. political commitment to missile defenses began to strengthen during the 1990s; and the United States withdrew from the ABM Treaty in 2002. Moreover, in spite of its threat to withdraw from START if the United States withdrew from the ABM Treaty, Russia remained a party to START and continued to negotiate further reductions on strategic offensive weapons. An argument can be made that the same pattern may not hold true in the coming decade if the United States and Russia ratify the New START Treaty with Russia's unilateral statement on missile defenses attached. The United States may be so committed to the New START Treaty and further reductions in U.S. and Russian offensive weapons, both as a way to reset the U.S-Russian relationship and as a step on the path to a world free of nuclear weapons, that it would not be willing to upset the process by pursuing expansive ballistic missile defense programs. Some who have criticized START have also noted that because the Treaty's 10-year life span would outlast the Obama Administration, a future Administration could be faced with the choice between arms control and ballistic missile defense regardless of its own preferred approach in either policy area. On the other hand, the pattern exhibited during the original START negotiations and the 1990s could repeat itself in the coming decade. During the 1990s, the U.S. commitment to missile defense was less solid and secure than it is today. Although President Reagan and President George H.W. Bush were strong supporters of missile defenses, Congress was less enthusiastic. The Clinton Administration initially shifted focus from the George H.W. Bush Administration's GPALs to theater missile defenses because of Desert Storm and threat assessments of short-range ballistic missile proliferation. By the latter half of the decade, the Clinton Administration promoted an NMD research and development program that could lead to deployment within a few years and would have required modification of the ABM Treaty or its replacement. Yet, even during this time, the United States did not hold back funding for ballistic missile defenses out of concern for any Russian reaction. Moreover, the analysis presented in this report suggest that the U.S. commitment to missile defense is now politically broader and deeper than it was during the 1990s. The Obama Administration has displayed a commitment to continue expanding ballistic missile defenses through its Ballistic Missile Defense Review and with its proposed budget for ballistic missile defense programs. Congress has also grown more supportive of ballistic missile defenses, appropriating most of the funds requested by the executive branch without challenging the underlying rationale for missile defense programs. Moreover, as was noted above, the Obama Administration refused, throughout the New START negotiations, to accept Russian proposals for limits on missile defense programs, and even seemed willing to walk away from the negotiations to protect U.S. ballistic missile defense programs. Even though the next Administration may not share the priorities of preceding Administrations, few would project a waning of the U.S. commitment to ballistic missile defenses, particularly as nations who could threaten the United States continue to acquire more capable ballistic missiles. At the same time, although Russia may continue to try to link U.S. ballistic missile defense programs to negotiations on offensive reductions, few would project Russia abandoning New START in the coming decade. Its Soviet-era missile forces are continuing to age, and it cannot produce new systems quickly enough to replace these older systems or even to retain the numbers of missiles permitted by the New START Treaty. This would not likely change even if it were to abandon the treaty. A treaty that imposes equal limits on U.S. and Russian offensive forces may be the only way that Russia can maintain a measure of parity with the United States on strategic offensive forces. Under these circumstances, the priorities displayed by the United States and Soviet Union during the original START talks and by the United States and Russia during the New START talks may continue into the coming decade. The United States may continue to place a higher priority on its ballistic missile defense programs than on offensive reductions and Russia may continue to place a higher priority on securing equal limits on U.S. and Russian offensive forces than on restraining or reducing U.S. ballistic missile defense programs.

Summary: The United States and Russia signed the New START Treaty on April 8, 2010, and it awaits Senate consideration. The preamble to the Treaty contains a "provision on the interrelationship of strategic offensive arms and strategic defensive arms." This statement does not contain any limits on current or planned U.S. missile defense programs. However, some analysts have questioned whether Russia's threat to withdraw from New START if the United States expands its missile defense capabilities might have a "chilling effect" on U.S. missile defense plans and programs. Ballistic missile defenses have been an issue in U.S.-Soviet and U.S.-Russian arms control talks since the 1970s. During the Cold War, the nations sought to balance limits on offensive weapons and defensive weapons so that they could maintain "strategic stability," which refers to the ability of each side to launch a retaliatory strike after absorbing a first strike by the other side. Most analysts argued that missile defenses would undermine stability by protecting the attacking nation from the effects of a second strike; some argued that defenses could enhance stability by undermining the effectiveness of the first strike. The former construct was evident in the Strategic Arms Limitation talks (SALT), where the United States and Soviet Union agreed to limit both offensive forces and ballistic missile defenses. The latter formula was evident in the Reagan Administration's advocacy of the Strategic Defense Initiative (SDI). During the Strategic Arms Reduction Talks (START) in the 1980s, the Soviet Union sought to link limits on offensive weapons to limits on ballistic missile defenses and SDI. The United States rejected this linkage, and the 1991 START Treaty did not contain any limits on missile defenses. The Soviet Union issued a unilateral statement indicating that it would withdraw from START if the United States violated the 1972 Anti-Ballistic Missile (ABM) Treaty. However, when the United States withdrew from the ABM Treaty in 2002, Russia did not withdraw from START. Moreover, during the 1990s, when the United States faced Russia's threat to withdraw from START, the U.S. commitment to missile defense strengthened. In the early part of the decade, U.S. missile defense programs focused on the threat posed by shorter- and medium-range missiles, like those the United States encountered during Desert Storm. However, growing concerns in the latter half of the decade about long-range ballistic missiles fueled an increase in emphasis and growing funding on national missile defenses. The Clinton Administration initiated a program, known as 3+3, that explored the technical feasibility of deploying such defenses in the early part of the 2000s. When the Bush Administration took office, it withdrew the United States from the ABM Treaty and began to deploy long-range missile defense interceptors in Alaska and California. A review of the budget data on ballistic missile defenses shows that U.S. funding for these programs grew steadily through the 1990s. Funding has leveled off in the past 10 years, but support for missile defense has been strong across the political spectrum in the United States. Congressional appropriations have nearly equaled the budget requests for these programs each year. The Obama Administration has also emphasized its support for ballistic missile defenses, in both its Ballistic Missile Defense (BMD) Review and its budget request for FY2011. This report may be updated as needed.