Prompt global strike (PGS) would allow the United States to strike targets anywhere on Earth with conventional weapons 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 mission, but it has restricted funding and suggested some changes in funding for specific programs. Many analysts believe that the United States should use long-range ballistic missiles armed with conventional warheads for the PGS mission. These weapons would not substitute for nuclear weapons in the U.S. war plan but would, instead, 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. 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 considered deploying conventional warheads on their long-range ballistic missiles. The Navy sought to deploy conventional warheads on a small number of Trident II submarine-launched ballistic missiles. In FY2008, Congress rejected the requested funding for this program, but the Navy has continued to consider the possibility of deploying intermediate-range technologies for the prompt strike mission. The Air Force and DARPA are developing a hypersonic glide delivery vehicle that could deploy on a modified Peacekeeper land-based ballistic missile -- a system known as the Conventional Strike Missile (CSM). In FY2008, Congress created a single, combined fund for the conventional prompt global strike (CPGS) mission. This fund is supporting research and development into the CSM and two possible hypersonic glide vehicles.