Carnegie’s James M. Acton visited the Carnegie Moscow Center to present his most recent report Silver Bullet? Asking the Right Questions About Conventional Prompt Global Strike (2013). Rather than advocating for or against Conventional Prompt Global Strike (CPGS), Acton engaged in a discussion of the issues that ought to be considered by both the United States and Russia before acquisition decisions are made. Carnegie Moscow Center’s Dmitri Trenin and Natalia Bubnova moderated. Carnegie Moscow Center’s Alexei Arbatov participated.

The Purpose of Conventional Prompt Global Strike Technology

  • Technology Ahead of Strategy: According to Acton, although technologists argue in favor of the development of CPGS system, it is not driven by a clear strategic need. As Acton pointed out, some would go as far as to name it “a missile looking for mission.” The idea first originated decades ago when consideration was given to placing conventional warheads on nuclear-armed ballistic missiles that were surplus to requirements.  
  • Military Applications: Acton outlined four possible missions for CPGS weapons (while emphasizing that the Pentagon has not made any doctrinal decisions): to counter antisatellite weapons; suppress or defeat sophisticated defensive capabilities; deny a new proliferator the ability to employ its nuclear arsenal; and kill high-value terrorists. 
  • Research and Development: Acton stressed that even if the United States decided to embark on the acquisition process—which is not guaranteed in the current financial environment—CPGS weapons would unlikely be deployed before the mid-2020s.

Military Weaknesses

  • GPS Denial: Acton pointed out that CPGS weapons are likely to rely on Global Positioning System (GPS) signals for navigation, making them vulnerable to GPS denial. The feasibility of providing for back-up guidance is very unclear, he added.
  • Vulnerability to Advanced Air and Missile Defenses: Acton explained that CPGS weapons travel too fast to deliver penetrating weapons capable of reaching underground targets. To deliver penetrating warheads, they would have to slow down, making them vulnerable to advanced air and missile defenses. 
  • Enabling Capabilities: Acton argued that insufficient attention has been paid to enabling capabilities—particularly intelligence surveillance and reconnaissance—which CPGS weapons would rely on. For example, if the United States wanted to attack mobile targets with CPGS, it would need to develop a globe-spanning network of satellite-based radars—plans for such a network have repeatedly been canceled.

Possible International Ramifications

The U.S. CPGS program has sparked a number of concerns in Russia. Acton and Arbatov warned of some incompletely considered risks.

  • “Warhead Ambiguity:” The most discussed strategic risk is that a CPGS weapon would be mistaken for a nuclear weapon. In order to try to overcome warhead ambiguity, the United States has prioritized investment in boost-glide technology with a non-ballistic trajectory. 
  • Destination and Target Ambiguity: Acton expressed his concern over potential risks created by boost-glide systems. These non-ballistic CPGS weapons travel at a low altitude (30 to 40 km), which makes them essentially invisible to early warning radars (although their launch would be visible to satellites). Moreover, boost-glide weapons are capable of maneuvering in the atmosphere. The unobservable and unpredictable trajectory of boost-glide weapons could create a serious risk of escalation in a conflict. Acton concluded that it was not obvious whether conventional ballistic missiles really should be more worrying to Russia than boost-glide systems.
  • Russia’s Concerns: Arbatov highlighted two issues of particular concern to Russia. First, due to the unpredictability of the direction and the fast-strike capability of boost-glide weapons, Russia might not have time to deploy counter-measures and to count on its launch-on-warning capability. The second concern is that boost-glide systems may be armed with nuclear weapons. Dilemmas in perception would emerge and Russia may risk responding to a conventional strike with a nuclear weapon.
  • Further Concerns: Arbatov added further causes for concern. Because of the warning-time problem, boost-glide systems—with conventional or small-yield nuclear weapons—would be perceived in Russia as an ideal weapon for decapitation. Accountability under an arms control treaty would not solve the problem and there is little to no experience with inspections of such kind. The second issue relates to the possibility of deploying intermediate-range systems on ships and submarines, which could serve as an argument for Russia to withdraw from the Intermediate-Range Nuclear Forces Treaty.

Key Recommendations for the United States and Russia

  • Correcting Negative Perceptions: While the United States wants to work with Russia on solving the “warhead ambiguity” issue, the most acute Russian fear relates to the perceived ability of CPGS to put Russia’s nuclear forces at risk. At the same time, Acton added, neither of the countries has sufficiently considered potential risks of boost-glide weapons.
  • Cooperative Confidence Building: In order to minimize strategic risks, Acton called for the United States and Russia to cooperate on confidence building measures. These could include inspections to demonstrate that CPGS weapons have non-nuclear warheads, declarations on acquisition plans, exchanges of data about when and where CPGS weapons would be deployed, launch notifications, and a joint study on the extent of the threat that CPGS weapons might pose to nuclear silos. Some of these measures could be applied to non-prompt weapons as well, Acton added.
  • Arms Control Treaties: Acton supported making all CPGS systems accountable in any future U.S.-Russian arms control treaty. However, he acknowledged that prospects for further arms control are not good at the moment, given the existing disagreements over ballistic missile defense, weapons in space, tactical nuclear weapons, and non-prompt strategic conventional weapons.


Acton concluded by expressing hope that the United States and Russia engage in a serious dialogue. If the issues are not seriously discussed between the two countries today, it will be much harder to do so when acquisition decisions have been taken and when positions become much more entrenched.