From the Summary: "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. 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 nuclear weapons: a new low-yield warhead for submarine-launched ballistic missiles and a new sea-launched cruise missile. The Biden Administration may reconsider these weapons when it conducts its Nuclear Posture Review in the latter half of 2021."
CRS Report for Congress, RL32572
Congressional Research Service: https://crsreports.congress.gov/