Conventional Prompt Global Strike and Long-Range Ballistic Missiles: Background and Issues [February 3, 2017] [open pdf - 893KB]
"Conventional prompt global strike (CPGS) weapons would allow the United States to strike targets anywhere on Earth in as little as an hour. This capability 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 [prompt global strike] mission, but it has restricted funding and suggested some changes in funding for specific programs. CPGS weapons would not substitute for nuclear weapons, but would supplement U.S. conventional capabilities. They 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. [...] This report will be updated as needed."
CRS Report for Congress, R41464
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html