The following is the Congressional Research Service Feb. 13, 2018 report, Nonstrategic Nuclear Weapons.
From the Report:
Recent debates about U.S. nuclear weapons have questioned what role weapons with shorter ranges and lower yields can play in addressing emerging threats in Europe and Asia. These weapons, often referred to as nonstrategic nuclear weapons, have not been limited by past U.S.- Russian arms control agreements, although some analysts argue such limits would be of value, particularly in addressing Russia’s greater numbers of these types of weapons. Others have argued that the United States should expand its deployments of these weapons, in both Europe and Asia, to address new risks of war conducted under a nuclear shadow. The Trump Administration addressed these questions in the Nuclear Posture Review released in February 2018, and determined that the United States should acquire two new types of nonstrategic nuclear weapons: a new low-yield warhead for submarine-launched ballistic missiles and a new sealaunched cruise missile.
During the Cold War, the United States and Soviet Union both deployed nonstrategic nuclear weapons for use in the field during a conflict. While there are several ways to distinguish between strategic and nonstrategic nuclear weapons, most analysts consider nonstrategic weapons to be shorter-range delivery systems with lower-yield warheads that might be used to attack troops or facilities on the battlefield. They have included nuclear mines; artillery; short-, medium-, and long-range ballistic missiles; cruise missiles; and gravity bombs. In contrast with the longer-range “strategic” nuclear weapons, these weapons had a lower profile in policy debates and arms control negotiations, possibly because they did not pose a direct threat to the continental United States. At the end of the 1980s, each nation still had thousands of these weapons deployed with their troops in the field, aboard naval vessels, and on aircraft.
In 1991, the United States and Soviet Union both withdrew from deployment most and eliminated from their arsenals many of their nonstrategic nuclear weapons. The United States now has approximately 500 nonstrategic nuclear weapons, with around 200 deployed with aircraft in Europe and the remaining stored in the United States. Estimates vary, but experts believe Russia still has between 1,000 and 6,000 warheads for nonstrategic nuclear weapons in its arsenal. The Bush Administration quietly redeployed some U.S. weapons deployed in Europe, while the Obama Administration retired older sea-launched cruise missiles. Russia, however seems to have increased its reliance on nuclear weapons in its national security concept.
Analysts have identified a number of issues with the continued deployment of U.S. and Russian nonstrategic nuclear weapons. These include questions about the safety and security of Russia’s weapons and the possibility that some might be lost, stolen, or sold to another nation or group; questions about the role of these weapons in U.S. and Russian security policy; questions about the role that these weapons play in NATO policy and whether there is a continuing need for the United States to deploy them at bases overseas; questions about the implications of the disparity in numbers between U.S. and Russian nonstrategic nuclear weapons; and questions about the relationship between nonstrategic nuclear weapons and U.S. nonproliferation policy.
Some argue that these weapons do not create any problems and the United States should not alter its policy. Others argue that the United States should expand its deployments of these weapons in response to challenges from Russia, China, and North Korea. Some believe the United States should reduce its reliance on these weapons and encourage Russia to do the same. Many have suggested that the United States and Russia expand efforts to cooperate on ensuring the safe and secure storage and elimination of these weapons; others have suggested that they negotiate an arms control treaty that would limit these weapons and allow for increased transparency in monitoring their deployment and elimination. The 115th Congress may review some of these proposals.