Assessing the Need to Regulate U.S. Conventional Prompt Global Strike Systems

Hypersonic Test Vehicle (HTV) 2

The concept of “strategic stability” played a featured role in the administration of U.S. President Barrack Obama’s 2010 Nuclear Posture Review (1). It came on the heels of Obama’s 2009 speech in Prague, in which the president declared that the United States had a moral responsibility to lead a global quest to eliminate all nuclear weapons. The posture review acknowledged that the United States could diminish its dependence on nuclear weapons because of the unrivaled growth in American conventional weapons superiority along with its deployment of missile defenses. Of course, achieving the elimination of all nuclear weapons, no less deep reductions, hinges on the active cooperation of other nuclear-armed states, most notably the Russian Federation. The obvious but underappreciated dilemma that the United States faces is convincing and reassuring the Russian Federation that American advantages in conventional weapons capabilities represent a sufficiently stable future context within which Russia would be willing to eliminate its own nuclear weapons. For this reason, Russia has already expressed grave concern about U.S. intentions to deploy new Conventional Prompt Global Strike (CPGS) delivery systems coupled with its growing arsenal of missile defenses. This short paper assesses the chief challenges the United States faces in allaying Russian concerns about CPGS deployments.

Status of CPGS Programs

Three key service programs now are center stage under the consolidated CPGS program. The U.S. Air Force began the Conventional Strike Missile (CSM) program in 2008, and, after the demise of the U.S. Navy’s attempt to offer the Trident missile as the quickest and most effective path to a CPGS option, the air force CSM now occupies the lead position instead. Based on land – probably either on the U.S. west or east coast – the CSM would employ boost-glide technologies and follow a substantially lower depressed trajectory than existing nuclear-armed ballistic missiles. After separation, the payload would travel hypersonically to the target while having the capacity to execute substantial cross-range maneuvers. Two benefits flow from such maneuverability: high accuracy and avoiding flight over hostile countries. The CSM launch vehicle would be the Orbital Sciences’ Minotaur IV space launch vehicle with a proven track record of over 50 flights. The air force had hoped to reach an operational capability by 2012 (with one ready missile and two spares), but it now appears that the CSM might not be ready until well after the middle of this decade. This is due to the substantial testing that remains for reentry bodies that must undergo at least five demonstration flights. To date, the CSM has not undergone any successful hypersonic flight tests (2).

The second CPGS contender is the Hypersonic Test Vehicle no. 2 (HTV-2), funded by the Defense Advanced Research Projects Agency (DARPA), the Pentagon defense organization charged with pushing the state of the art in new military technologies. The goal of the HTV-2 is development of a vehicle that can ride along the earth’s upper atmosphere at hypersonic speeds of more than 21,000 kilometers per hour. America’s largest defense contractor, Lockheed Martin, is developing the vehicle, which will also serve as the payload delivery vehicle for the air force CSM program. However, after two flight test failures (2010, 2011), and the brief achievement of a speed of Mach 20, it is clear that the vehicle thus far cannot maintain aerodynamic control for a full flight test, no less the entire objective mission distance. Given the extraordinarily tight defense budget that is likely to prevail for some time, the Pentagon decided to allocate a mere $2m in the FY2014 budget, which will not support further HTV-2 testing while the Pentagon seeks a cheaper, less risky CPGS alternative. (3)

The third option under the consolidated Pentagon CPGS program is the U.S. Army’s Advanced Hypersonic Weapon (AHW), which from the outset was seen as a way to reduce the risk associated with DARPA’s HTV-2 endeavor. Indeed, the AHW’s one flight test, in November 2011, was successful, allowing the hypersonic glide vehicle to achieve a range of 3,860 kilometers. Of course, the AHW’s shorter range would mean that it has to be forward deployed to meet the needs of the CPGS mission.  Nevertheless, unlike its more challenging DARPA cousin, the army’s AHW received Pentagon support for modest additional funding in FY2014 to permit one more test. (4)

Appraising the Risks and Benefits of CPGS

The dangers and risks of employing even a niche CPGS capability – consisting of 20 or so systems – no less hundreds or more, greatly exceed the benefits; moreover, more suitable, if less prompt, alternatives exist to deal with fleeting targets. The chief risks include creating strong preemption incentives, not only for states correctly perceiving they are in the gun sights of CPGS weapons, but also in nations considering emulating this American precedent to undertake theire own form of prompt long-range strike capability. Japan’s current contemplation of such an option, in a region rife with states brandishing new long-range strike systems, comes immediately to mind (5). Strategic stability is also threatened by the inevitable ambiguity surrounding whether or not an incoming CPGS attack is conventional or nuclear. Compressed circumstances surrounding such a scenario could foster unwanted erratic behavior. But the true Achilles heel of the CPGS concept is the unprecedented demands placed on the intelligence community to provide decision-makers with “exquisite” intelligence (6), all within an hour’s timeframe. Such compressed conditions leave decision-makers with virtually no time to appraise the direct and potentially unintended consequences of their actions.

Compared with the shortcomings of CPGS, the two benefits specified by supporters of CPGS are at best paltry. The first is having a prompt strike option in case of the possible detection of a fleeting terrorist target with a nuclear weapon located in a neutral country, or a rogue state appearing to ready a nuclear-armed missile. The second is the belief that CPGS reduces the possibility that the United States may have to use nuclear weapons instead to defend its interests. In case of the first presumed benefit, while even proponents will admit that such scenarios are highly improbable, the combination of a much higher probability of poor intelligence support and the inadvertent start, in the case of a state-based scenario, of an otherwise avoidable conventional, or worse, nuclear war, simply is too high a risk to bear. Fortunately, there are a plethora of alternative, if less prompt, attack means available to U.S. decision-makers. As for CPGS reducing the need to employ a nuclear solution, it is rather America’s unrivaled conventional superiority that has permitted the U.S. military to possess a multitude of options vastly more sensible than employing a nuclear solution to deal with such low-probability scenarios.

Lastly, should the United States decide to pursue a niche CPGS capability or more, and still wish to maintain the strategic stability and deep nuclear reductions it argues are critical for global security, it must be willing to accept counting rules not just for existing missiles that deliver conventional warheads along a ballistic trajectory but also for new types of delivery systems, such as boost-glide vehicles launched along a depressed trajectory. This is particularly imperative for numbers exceeding a niche-like capability, which might begin to truly threaten Russian and smaller nuclear arsenals.

Accommodating Russian Concerns

In considering to what extent the United States should accommodate Russian concerns about counterforce capabilities of CPGS in future bilateral negotiations, it is important to review what the New START treaty of 2010 concluded with respect to Russian concerns. In negotiations, the United States reportedly told the Russian side that they did not plan to deploy enough CPGS systems to threaten Russia’s strategic retaliatory capability (7). The preamble to the treaty, however, does state that both countries are “mindful of the impact of conventionally armed ICBMs and SLBMs on strategic stability.” (8) The U.S. side was willing to count ballistic missiles armed with conventional warheads in the treaty’s limits as if they were nuclear. Importantly, this was done not because the U.S. side agreed with Russian concerns about the counterforce potential of such conventional weapons; rather, should the United States proceed to arm previously nuclear ballistic missiles with a conventional payload, it would be virtually impossible to know the difference between a nuclear- and conventional-armed missile, rendering treaty compliance problematic. (9)

Should the United States proceed to deploy what is very likely to be a niche capability, extant New START counting rules would apply if the choice is a missile that delivers reentry vehicle(s) on a ballistic missile trajectory. On the other hand, were the United States to deploy a boost-glide CPGS weapon – launched along a depressed trajectory using a hypersonic glide vehicle to deliver its weapons to the target – this new type of system would not be subject to New START counting rules. This is because, unlike traditional ballistic missiles, the Russians could readily detect the difference, thus avoiding the threat ambiguity issue. However, in the case of a U.S. wish to deploy such a non-ballistic system, New START provides Russia with the right to question, in a Bilateral Consultation Commission, whether or not such a weapon should be subject to extant counting rules (10). As long as the United States remains committed simply to a niche capability, consenting to counting rules for such a limited deployment of boost-glide systems seems eminently reasonable (11). Should a future U.S. Administration wish to deploy larger numbers of CPGS weapons, they should still be subject to counting rules.


(1) US Department of Defense (2010), Nuclear Posture Review Report, April, Washington DC.

(2) Ibid., p. 1 & pp. 16-17. For details on the Minotaur space launch vehicle

(3) Ibid., pp. 18-19. Also see Grossman, Elaine M (2013), ‘Pentagon Unveils New Plan for Conventional Submarine-Based Ballistic Missiles’, National Journal, updated, 29 May, 2013.

(4) Woolf, Amy F (2013), ‘Conventional Prompt Global Strike and Long-Range Ballistic Missiles: Background and Issues’, Congressional Research Service Report for Congress, R41464, 26 April 2013, pp. 19-20.

(5) On the spread of formal preemption doctrines not only in Northeast Asia, but also South Asia and the Middle East, see Gormley, Dennis M (2008), Missile Contagion: Cruise Missile Proliferation and the Threat to International Security, Naval Institute Press, Annapolis, pp. 125-133 and 136-145.

(6) Secretary of Defense Donald Rumsfeld in 2001 Nuclear Posture Review coined the notion of “exquisite” intelligence.

(7) Woolf, p. 37.

(8) Cited in Ibid.

(9) Ibid.

(10) Under Article 5 of the treaty, the U.S. would still reserve the right to develop and test such a weapon.

(11) Recalling the provenance of CPGS, Russia surely must assume that a future U.S. administration might be prone to go down a more robust path than perhaps the current administration is willing to entertain.