	Introduction

The United States and Soviet Union signed the Strategic Arms Reduction Treaty (START) on July 31, 1991. The United States and Russia held several meetings in the latter years of the Bush Administration to discuss the options for continuing their bilateral arms control relationship after START, but did not reach an agreement on whether to extend START or on how to replace it. The United States and Russia signed the new Treaty on April 8, 2010. Counting Rules

START counts each deployed ICBM and its associated launcher, each deployed SLBM and its associated launcher, and each deployed heavy bomber as a single delivery vehicle under the Treaty limit of 1,600 delivery vehicles. The parties have also been required to exchange copious amounts of detailed data on the technical characteristics of the treaty-limited items. The parties to a treaty use a wide variety of means to collect information—or monitor—the forces and activities of the other parties. Some of these monitoring systems, such as overhead satellites, operate outside the territories of the treaty parties. To achieve this goal, the countries have had to
establish the number and location of deployed and stored ballistic missiles and deployed bombers when the Treaty entered into force; confirm the technical characteristics of existing types of weapons and establish the measurements for new types of weapons; add the number of ballistic missiles and heavy bombers deployed after the treaty entered into force; subtract the number of ballistic missiles and heavy bombers eliminated, according to treaty rules, during the life of the treaty; track treaty-limited items when they move between declared facilities; monitor the armament on permitted systems, to confirm that missiles and bombers are deployed with the numbers and types of warheads permitted by the START data base; and monitor ballistic missile flight tests to determine the characteristics of different types of ballistic missiles. Russia indicated that it wanted to follow START with a new formal treaty that would be "similar in size and complexity to START" and would use many of the same definitions and counting rules as START. They indicated that the subject of new agreement "will be the reduction and limitation of strategic offensive arms"; that they would seek to reduce their forces to levels below those in the 2002 Moscow Treaty; and that the new agreement would "mutually enhance the security of the Parties and predictability and stability in strategic offensive forces, and will include effective verification measures drawn from the experience of the Parties in implementing the START Treaty." This transparency regime would have been far less detailed and complex than START. The Obama Administration altered many of the U.S. positions in the negotiations on a new START Treaty. The United States, in contrast, still had 1,188 delivery vehicles that count under the START Treaty. Possible Goals for the START Process

Although the United States and Russia are currently pursuing negotiations on a new START Treaty, that did not complete this task before START expired on December 5, 2009. This is the approach outlined by Presidents Obama and Medvedev during their meeting in April 2009, where they pledged to achieve new and verifiable reductions "in a step-by-step process." Although both nations remain optimistic, the United States and Russia could choose from a number of other options for the future of their arms control relationship if they fail to complete a new treaty in the weeks or months after START expires. They could pursue less formal arrangements to manage their nuclear forces. If the parties wanted to retain some of the START monitoring and verification provisions in the near term, without extending the Treaty for five years, they could possibly agree to extend START for a shorter period of time, perhaps two years, while they negotiate a new Treaty. As the Bush Administration eventually suggested, the two sides could agree, without signing a formal Treaty, to continue to implement some of the monitoring provisions in START so that they could both gather information needed to verify compliance with the Moscow Treaty and retain the cooperative relationship that had developed during START's verification process. This might allow the United States and Russia to sustain their confidence in their knowledge of each other's nuclear weapons deployments. This report will be updated as the process moves forward.
The United States and Russia signed a new strategic arms reduction treaty (New START) on April 8, 2010. This Treaty replaces the original START Treaty, which the United States and Soviet Union signed in July 1991. START entered into force in December 1994 and expired on December 5, 2009.
The original START Treaty counted each deployed ICBM, SLBM, and bomber as a single delivery vehicle under the Treaty limit of 1,600 delivery vehicles and attributes an agreed number of warheads to each deployed delivery vehicle. This attribution rule provides the total number of warheads that count under the 6,000 warhead limit in the Treaty. To verify compliance with START, each side monitors the numbers and locations of ballistic missiles, launchers and heavy bombers deployed by the other country. The parties use a wide variety of means to collect information—or monitor—these forces and activities. Some of these monitoring systems, such as overhead satellites, operate outside the territories of the treaty parties. They have also been required to exchange copious amounts of data on locations, operations, and technical characteristics of the treaty-limited items. This verification regime has allowed the parties to remain confident in each other's compliance with the Treaty.
The United States and Russia began to discuss their options for arms control after START in mid-2006. During the Bush Administration, they were unable to agree on a path forward. Neither side wanted to extend START in its current form, as some of the Treaty's provisions have begun to interfere with some military programs on both sides. Russia wants to replace START with a new Treaty that would further reduce deployed forces while using many of the same definitions and counting rules in START. The United States initially did not want to negotiate a new treaty, but, under the Bush Administration, would have been willing to extend, informally, some of START's monitoring provisions. In 2008, the Bush Administration agreed to conclude a new Treaty, with monitoring provisions attached, but this Treaty would resemble the far less formal Strategic Offensive Reductions Treaty that the two sides signed in 2002. In December 2008, the two sides agreed that they wanted to replace START before it expired, but acknowledged that this task would have to be left to negotiations between Russia and the Obama Administration. President Obama and President Medvedev agreed at their meeting on April 2, 2009, to pursue "new and verifiable reductions" in their strategic offensive arms. The two sides have just completed negotiations on new START Treaty.
The United States and Russia could have chosen from a number of options for the future of their arms control relationship. They have allowed START to lapse while negotiating a new Treaty, but they could have extended START for five years during this process. They could also have extended START, then amended it to ease some of the outdated provisions. Instead of negotiating a new Treaty, they could have pursued less formal arrangements to manage their nuclear forces. Moreover, if a new treaty includes further reductions in nuclear weapons, it could use some START definitions and counting rules or the less formal Moscow Treaty declarations.
This report will no longer be updated. Additional information on the New START Treaty can be found in CRS Report R41219, The New START Treaty: Central Limits and Key Provisions.