On May 24, 2002, President Bush and Russia's President Putin signed the Strategic Offensive Reductions Treaty, known as the Moscow Treaty, that would limit strategic offensive nuclear weapons. In it, the two nations stated that they would reduce strategic nuclear weapons to between 1,700 and 2,200 warheads by December 31, 2012. The treaty lapsed, however, on February 5, 2011, when the New START Treaty entered into force and superseded the Moscow Treaty. Press reports and public statements in 2002 hailed the Moscow Treaty because it seemed to impose sharp reduction from the 6,000 warhead level mandated by the 1991 Strategic Arms Reduction Treaty (START). However, this treaty differed from past arms control treaties in that it did not include any of the detailed definitions, counting rules, elimination procedures, or monitoring and verification provisions that have become common in treaties signed since the late 1980s. Consequently, a simple comparison of warhead levels counted under START and warhead levels permitted by the Moscow Treaty does not provide a complete view of the likely effects of the Moscow Treaty. This report provides a brief overview of the two nations' objectives when they began discussions on this treaty and a summary of how they resolved these differences when concluding the negotiations. It then describes the key provisions in the treaty and presents illustrative forces that each side might deploy in the next 10 years. It offers a brief assessment of how each nation fared in achieving its objectives when negotiating this agreement and a summary of reaction from U.S. and Russian commentators. It concludes with a brief review of the issues raised during the treaty's ratification debates. The first signs of a new arms control dialogue between the United States and Russia appeared after President Bush and President Putin met in Genoa, Italy, during the G-8 summit in July 2001. At that time, the Presidents issued a statement saying that the two nations would "shortly begin intensive consultations on the interrelated subjects of offensive and defensive systems." Each nation had sharply divergent views on the substance and goals for these talks. When discussing offensive force reductions, Russia argued that the two sides should seek agreement on a formal treaty that would limit each side to 1,500 nuclear weapons. The Bush Administration wanted to pursue unilateral reductions, with each side setting its own nuclear force size and structure, but it would not offer any details on U.S. plans in this regard until the Department of Defense completed its review of U.S. nuclear posture. This internal review concluded in November, 2001. During a summit meeting with President Putin in Washington, on November 13, 2001, President Bush announced that the United States would reduce its "operationally deployed" strategic nuclear warheads to a level between 1,700 and 2,200 over the next decade." The President stated that the United States would reduce its forces unilaterally, without signing a formal agreement with Russia. He stated that the two nations did not need "endless hours of arms control discussions" and arms control agreements "to reduce our weaponry in a significant way." He offered to "write it down on a piece of paper," but he indicated that he believed a handshake would be good enough. President Putin responded by stating that he appreciated the President's decision to reduce U.S. nuclear forces and stated that Russia "will try to respond in kind." He did not offer a target number for the reductions at that time, but he had stated several times in previous months, and repeated in December 2001, that Russia planned to reduce its forces to 1,500 warheads. He did, however, indicate that he would like to use the formal arms control process to reduce U.S. and Russian forces. He emphasized that the two sides should focus on "reaching a reliable and verifiable agreement on further reductions of the U.S. and Russian weapons." The two sides began discussions on the form and content of a new agreement in January 2002. Official comments and press reports from January and February 2002 demonstrate that the two sides' opening positions contained significant differences. By the time they concluded the treaty in May, they had resolved most of their differences over form and content. In content, the treaty encodes U.S. proposals. In form, it reflects Russia's desire for a formal, "legally binding" document. Russia entered the negotiations seeking a "legally binding document" that would provide "predictability and transparency" and ensure for the "irreversibility of the reduction of the nuclear forces." In essence, Russia sought a treaty that followed the model used in the Strategic Arms Reduction Treaties (START I and START II), with similar counting rules, elimination rules, and verification procedures, but a lower limit on warheads. After the Bush Administration's report on the Nuclear Posture Review indicated that the United States planned to hold warheads removed from deployment in storage, Russia also insisted that the new treaty require the elimination of these non-deployed warheads. This would contribute to the "irreversibility" of the limits; without such a provision, Russia argued the United States might return warheads to deployed systems and exceed the limits in the treaty in a relatively short amount of time. In addition, Russia wanted the treaty to contain a statement noting that the United States would limit its missile defense program so that defenses would not threaten the effectiveness of Russia's offensive forces. When the negotiations began, the United States did not plan to conclude a formal treaty that would include strict limits on deployed weapons. It wanted to maintain the flexibility to size and structure its nuclear forces in response to its own needs. The United States preferred a less formal process, such as the exchange of letters, in which the two nations would state their intentions to reduce their nuclear forces. They might conclude a joint declaration to provide for added transparency measures so that each side could "understand each other's force structures." Furthermore, the United States had no intention of including restrictions on missile defenses in an agreement outlining reductions in strategic offensive nuclear weapons. Press reports indicate that, within the Bush Administration, Pentagon officials argued strongly against incorporating any limits on offensive nuclear weapons in a "legally binding" arms control agreement. They wanted the United States to be able to reduce or increase its nuclear forces in response to changes in the international security environment. Secretary of State Powell, on the other hand, supported the conclusion of a "legally binding" agreement because he believed it would help President Putin's standing with domestic critics who opposed his policies towards the United States. The United States apparently began to move towards Russia's position in early February 2002. In a hearing before the Senate Foreign Relations Committee, Secretary of State Powell said that the framework "will be something that is legally binding, and we are examining different ways in which this can happen." According to Secretary Powell, the Administration could complete the agreement as an executive agreement, whose approval would be subject to a majority vote of both houses of Congress, or a formal treaty, which would require the consent of two-thirds of the members of the Senate. Some in the Pentagon, however, continued to oppose the conclusion of a treaty limiting strategic offensive nuclear weapons. They preferred to limit any "legally binding" provisions to procedures for verifying the number of deployed warheads. In testimony before the Senate Armed Services Committee in February, Undersecretary of Defense Douglas Feith said "we see no reason to try to dictate the size and composition of Russia's strategic forces by legal means" and "we do not believe it is prudent to set in stone the level and type of U.S. nuclear capabilities." President Bush appeared to endorse Secretary Powell's approach in March. He agreed to sign a legally binding agreement, noting that "there needs to be a document that outlives both of us." He also stated that the exact form of this "legally binding" document had not been decided. But he also endorsed the Pentagon's emphasis on verification. He indicated that the agreement should focus on verification, calling it "the most important thing." In mid-March, Senators Joseph Biden and Jesse Helms sent a letter to the White House reportedly "demanding" that the Administration submit the eventual agreement to the Senate as a treaty. They noted that "significant obligations by the United States regarding deployed U.S. strategic nuclear warheads" would "constitute a treaty subject to the advice and consent of the Senate." This letter demonstrated that both parties in the Senate agreed on the need to defend the Senate's prerogatives and supported its right to advise and consent on treaties. The White House did not accept the Senate's position immediately. However, when the President announced, on May 13, that the United States and Russia had reached an agreement, he stated that it would be a treaty. One Administration official noted that the Senators' position had contributed to the change in the U.S. position in discussions with Russia. The United States and Russia disagreed about several key issues that would be addressed by the proposed arms control agreement. These included the definitions and counting rules that the two sides would use to calculate how many warheads should count under the treaty's limits; the disposition of warheads removed from deployed systems; transparency and verification provisions; and potential restraints on missile defenses. The U.S. and Russian differences over how to count the weapons limited by the Moscow Treaty persisted throughout the negotiations. Russia proposed that the treaty use counting rules similar to those in START to calculate the number of warheads on deployed weapons. Under START, the parties assign a number of warheads to each type of deployed delivery vehicle (ICBMs, SLBMs, and heavy bombers.) They then "count" the number of deployed delivery vehicles and multiply by the "attributed" number of warheads to calculate the total number of warheads that would count under the treaty limits. To remove weapons from accountability, the parties could either reduce the deployed number of warheads on missiles, and change the "attributed" number of warheads (a process known as downloading) or destroy the delivery vehicles according to complex procedures outlined in the treaty.