The following is the May 8, 2018 Congressional Research Service report, Arms Control and Nonproliferation: A Catalog of Treaties and Agreements.
From the Report:
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 argued that the United States lacks a “willing partner” in Russia and, therefore, will not pursue further agreements as long as Russia remains in violation of existing arms control treaties.
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.