The following is the Feb. 14, 2020 Congressional Research Service report, Conventional Prompt Global Strike and Long-Range Ballistic Missiles: Background and Issues.

From the report

Members of Congress and Pentagon officials have placed a growing emphasis on U.S. programs to develop hypersonic weapons as a part of an effort to acquire the capability for the United States to launch attacks against targets around the world in under an hour. Conventional prompt global strike (CPGS) weapons may bolster U.S. efforts to deter and defeat adversaries by allowing the United States to attack high-value targets or “fleeting targets” at the start of or during a conflict. Congress has generally supported the PGS mission, but restricted funding for several years. Recently, efforts to develop a long-range prompt strike capability, along with other efforts to develop extremely fast hypersonic weapons, have garnered increased support.

CPGS weapons would not substitute for nuclear weapons, but would supplement U.S. conventional capabilities. Officials have argued that the long-range systems would provide a “niche” capability, with a small number of weapons directed against select, critical targets. Some analysts, however, have raised concerns about the possibility that U.S. adversaries might misinterpret the launch of a missile with conventional warheads and conclude that the missiles carry nuclear weapons. The U.S. Department of Defense (DOD) is considering a number of systems that might provide the United States with long-range strike capabilities.

The Air Force and Navy have both pursued programs that would lead to the deployment of conventional warheads on their long-range ballistic missiles. During the 2000s, the Air Force and the Defense Advanced Research Projects Agency (DARPA) sought to develop a hypersonic glide delivery vehicle that could deploy on a modified Peacekeeper land-based ballistic missile, but test failures led to the suspension of this program; research continues into a vehicle that might be deployed on air-delivered or shorter-range systems. In the mid-2000s, the Navy sought to deploy conventional warheads on a small number of Trident II submarine-launched ballistic missiles, but Congress rejected the requested funding for this program. Since then, the Pentagon has continued to develop a hypersonic glide vehicle, now known as the Alternate Reentry System, which could be deployed on long-range missiles. At present, it seems likely that this vehicle could be deployed on intermediate-range missiles on Navy submarines, for what is now known as the Prompt Strike Mission. Congress may review other weapons options for the deployment of hypersonic weapons, including bombers, cruise missiles, and possibly scramjets or other advanced technologies.

The Pentagon’s FY2021 budget request continues to show significant increases in funding for the Navy’s Conventional Prompt Strike (CPS) program. In FY2019 this program, which was funded through a DOD-wide account, received $278 million. The Navy received $512 million for this program in FY2020 and requested $1.008 billion for FY2021. The budget request shows continuing increases in funding over the next five years, with $5.3 billion allocated to the program between FY2021 through FY2025. This shows the growing priority placed on the program in the Pentagon and the growing interest in Congress in moving the program forward toward deployment.

When Congress reviews the budget requests for prompt global strike and other hypersonic weapons programs, it may question DOD’s rationale for the mission, reviewing whether the United States might have to attack targets promptly at the start of or during a conflict, when it could not rely on forward-based land or naval forces. It might also review whether this capability would reduce U.S. reliance on nuclear weapons or whether, as some critics have asserted, it might upset stability and possibly increase the risk of a nuclear response to a U.S. attack. At the same time, Members of Congress and officials in the Pentagon have both noted that Russia and China are pursuing hypersonic weapons, leading many to question whether the United States needs to accelerate its efforts in response, or whether an acceleration of U.S. efforts might contribute to an arms race and crisis instability.

Download the document here.