In this context, arms control and nonproliferation efforts are two of the tools that have occasionally been used to implement the U.S. national security strategy. During the Cold War, arms control played a key role in the relationship between the United States and Soviet Union. Further, the United States participated in many multilateral regimes that sought to limit the spread of nuclear, chemical, and biological weapons and their means of delivery. The Obama Administration sought to enhance the role of arms control and nonproliferation agreements in U.S. national security policy. These efforts have produced formal treaties and agreements that impose restrictions on U.S. military forces and activities, informal arrangements and guidelines that the United States has agreed to observe, and unilateral restraints on military forces and activities that the United States has adopted either on its own, or in conjunction with reciprocal restraints on other nations' forces and activities. However, the U.S. Senate's rejection of the CTBT, the Bush Administration's withdrawal from the ABM Treaty in 2002, and the U.S. rejection of a verification protocol for the Biological Weapons Convention led many nations to question the U.S. commitment to the arms control process. The Trump Administration has offered some support for existing arms control and nonproliferation tools; it noted, in the 2018 Nuclear Posture Review, that the United States continues to support the goals of the 1968 Nuclear Nonproliferation Treaty and that it would continue to abide by the terms of the 2010 New START Treaty, although it had not decided whether to extend it past 2021. The final section reviews treaties and agreements that address chemical, biological, and conventional weapons. The continuing Soviet build-up of strategic nuclear forces, along with the taking of U.S. hostages in Iran and other challenges to the U.S. international position in the late 1970s, combined with the perceived weaknesses to the Treaty to raise questions about whether the Senate would muster the votes needed to consent to the Treaty's ratification. At the same time, the Clinton Administration pursued research and technology development for national missile defenses (NMD). As the work on strategic offensive arms reductions was completed, a growing proportion of the funding focused on securing and eliminating chemical and biological weapons. Moreover, an increasing proportion of CTR funding has been allocated to projects outside the former Soviet Union, as the United States seeks to engage a greater number of nations as partners in the effort to secure vulnerable nuclear materials and other weapons of mass destruction. In recent years, biological weapons engagement programs have accounted for more than 70% of the CTR budget. Multilateral Nuclear Nonproliferation Activities

		The International Nuclear Nonproliferation Regime

The United States is a leader of an international regime that attempts to limit the spread of nuclear weapons through treaties, export control coordination and enforcement, and U.N. Security Council resolutions. Recent priorities have included biological threat reduction and radiological security. Ad Hoc Sanctions and Incentives

Other efforts—such as economic, military, or security assistance—may also help slow the proliferation of nuclear weapons. Non-Nuclear Multilateral Endeavors

The international community has concluded a number of arms control agreements, conventions, and arrangements that affect non-nuclear weapons. Two of these, the Conventional Armed Forces in Europe Treaty (CFE) and the Open Skies Treaty, were a part of the late-Cold War effort to enhance stability and predictability in Europe. Others seek to control the spread of technologies that might contribute to developing conventional or unconventional weapons programs. To address these concerns, the CFE parties negotiated a Flank Agreement, in early 1996. Negotiations began in 1968, but made little progress for many years. Agreement ... Agreement ...
Arms control and nonproliferation efforts are two of the tools that have occasionally been used to implement U.S. national security strategy. Although some believe these tools do little to restrain the behavior of U.S. adversaries, while doing too much to restrain U.S. military forces and operations, many other analysts see them as an effective means to promote transparency, ease military planning, limit forces, and protect against uncertainty and surprise. Arms control and nonproliferation efforts have produced formal treaties and agreements, informal arrangements, and cooperative threat reduction and monitoring mechanisms. The pace of implementation for many of these agreements slowed during the Clinton Administration, and the Bush Administration usually preferred unilateral or ad hoc measures to formal treaties and agreements to address U.S. security concerns. The Obama Administration resumed bilateral negotiations with Russia and pledged its support for a number of multilateral arms control and nonproliferation efforts, but succeeded in negotiating only a few of its priority agreements. The Trump Administration has offered some support for existing agreements, but has announced the U.S. withdrawal from the INF Treaty, citing Russia's violation of that agreement, and has not yet determined whether it will support the extension of the 2010 New START Treaty through 2026. It shows little interest in pursuing further agreements.
The United States and Soviet Union began to sign agreements limiting their strategic offensive nuclear weapons in the early 1970s. Progress in negotiating and implementing these agreements was often slow, and subject to the tenor of the broader U.S.-Soviet relationship. As the Cold War drew to a close in the late 1980s, the pace of negotiations quickened, with the two sides signing treaties limiting intermediate-range and long-range weapons. But progress again slowed in the 1990s, as U.S. missile defense plans and a range of other policy conflicts intervened in the U.S.-Russian relationship. At the same time, however, the two sides began to cooperate on securing and eliminating Soviet-era nuclear, chemical, and biological weapons. Through these efforts, the United States has allocated more than $1 billion each year to threat reduction programs in the former Soviet Union. These programs have recently reached their conclusion.
The United States is also a prominent actor in an international regime that attempts to limit the spread of nuclear weapons. This regime, although suffering from some setbacks in recent years in Iran and North Korea, includes formal treaties, export control coordination and enforcement, U.N. resolutions, and organizational controls. The Nuclear Nonproliferation Treaty (NPT) serves as the cornerstone of this regime, with all but four nations participating in it. The International Atomic Energy Agency not only monitors nuclear programs to make sure they remain peaceful, but also helps nations develop and advance those programs. Other measures, such as sanctions, interdiction efforts, and informal cooperative endeavors, also seek to slow or stop the spread of nuclear materials and weapons.
The international community has also adopted a number of agreements that address non-nuclear weapons. The CFE Treaty and Open Skies Treaty sought to stabilize the conventional balance in Europe in the waning years of the Cold War. Other arrangements seek to slow the spread of technologies that nations could use to develop advanced conventional weapons. The Chemical Weapons and Biological Weapons Conventions sought to eliminate both of these types of weapons completely.
This report will be updated annually or as needed.