The hypersonic arms race is in full swing: Countries around the world are investing staggering amounts of money into hypersonic weapons. And these are no longer limited to Russia, China, and the United States. The United Kingdom launched its own hypersonic initiative in 2023, while the Japanese defense ministry requested about 80 billion yen ($547 million) for the development and production of hypersonic weapons in fiscal year 2024. As a consequence, it should come as no surprise that a growing number of analysts have pondered the ways in which hypersonic weapons might affect strategic stability and how potential risks of nuclear escalation could be mitigated through arms control.
Exploring options for regulating hypersonic weapons is a laudable effort, but it runs the risk of finding a solution to the wrong problem. Limiting or even banning hypersonic weapons would merely constrain highly expensive niche capabilities that are unlikely to be used in large numbers, while leaving underlying and more serious escalation risks from the current U.S. warfighting concept unaddressed.
If the aim of arms control is to reduce the risk of nuclear escalation, then it would be more effective to devise warfighting concepts that support U.S. strategic objectives at less risk and less cost, rather than constraining hypersonic weapons themselves. This could include concepts such as offshore control, defensive defense, or the “spider in the web approach,” which all forgo strikes on the enemy’s mainland and would encourage U.S. allies to improve their own anti-access/area denial capabilities in order to deter enemy aggression while reducing the risk of nuclear escalation.
Hypersonic Escalation
According to numerous articles about hypersonic arms control, there are two main reasons why the employment of hypersonic weapons, which travel at a minimum of five times the speed of sound, could lead to miscalculation and nuclear escalation. Firstly, many hypersonic missiles are dual-capable, meaning that they can be equipped with either a conventional or a nuclear warhead. Secondly, due to their ability to maneuver during the entire flight, which sets them apart from ballistic missiles that have been around for many decades, it is all but impossible to predict with reasonable probability where they are going.
The presence of dual-capable weapon systems in theater is thought to pose risks of escalation because decision-makers can misjudge the nature of an incoming attack. If leaders receive early warning of a fast-approaching hypersonic missile and the missile type is determined to be dual-capable, they may assume the worst and launch their own nuclear weapons in response — even if the incoming missile was actually equipped with a conventional warhead.
The unpredictable flight path of hypersonic weapons, also referred to as target ambiguity, is considered another possible source of escalation since leaders may think that their strategic nuclear forces are under attack even if they were not. Given that they cannot know for certain at which target an incoming hypersonic missile is aimed until very late in the missile’s trajectory, decision-makers might reasonably conclude that their state’s nuclear forces are under attack if presented with a warning about an incoming hypersonic missile attack. As a consequence, they could decide to launch a nuclear counterstrike prior to impact, rather than running the risk of losing their second-strike retaliatory capability — a situation also known as the “use-them-or-loose-them” dilemma.
However, warhead and target ambiguity are nothing new. As a sizable number of experts have argued over the years, hypersonic weapons are best understood as an evolution of current missile technology that does not really introduce any truly revolutionary military capabilities — especially if compared to more traditional missile types. Essentially the same applies to their supposedly unique technical characteristics.
Old Problems, Faster
Ambiguous delivery systems have existed for several decades. Most notably, Russia and China field a wide array of dual-capable ballistic missiles and cruise missiles. These include the Chinese DF-26, which allows operators to rapidly swap conventional and nuclear warheads in the field, and the Russian Iskander-M, which has been used extensively in the war in Ukraine.
The United States does not currently possess any dual-capable missiles, but it did so until very recently: Between 1983 and 1991, the U.S. Navy deployed a nuclear-armed version of its Tomahawk Land-Attack Cruise Missile across its battleships, cruisers, destroyers, and attack submarines. This capability was fully retired in 2011 under the Obama administration, but it may soon find its way back into the U.S. nuclear arsenal in the form of the controversial sea-launched nuclear cruise missile. In 1986, the U.S. Air Force also secretly retrofitted a limited number of its nuclear-armed AGM-86B Air-Launched Cruise Missiles with a conventional 1,000 pound blast-fragmentation warhead. Additional stocks of nuclear-armed cruise missiles were converted to conventional-armed ones between 1996 and 2001, and the AGM-86C Conventional Armed Cruise Missile remained in service until early 2019.
Finally, many bombers and strike aircraft are dual-capable as well. The U.S. B-2 and B-52 strategic bombers, for example, can both launch conventional and nuclear cruise missiles, which also carries the risk of inadvertent escalation if an adversary misidentifies a conventional cruise missile for a nuclear one. This is precisely why former U.S. Secretary of Defense William J. Perry and former U.S. Assistant Secretary of Defense Andy Weber called for President Barack Obama to kill the Long-Range Standoff Weapon. Similarly, warhead ambiguity associated with traditional cruise missiles has informed proposals for limiting and eventually eliminating nuclear-armed cruise missiles altogether. It was also one of the reasons why some analysts in the mid-1970s were already describing cruise missiles as the end of arms control.
Target ambiguity isn’t a new problem either. Instead, it has been a feature of basically any cruise missile in service since the 1980s. Guided by terrain contour matching, GPS, or both, most cruise missiles today have the ability to fly along a predetermined route and maneuver around known hostile air defenses — all while flying at extremely low altitudes. This makes it extremely difficult, if not impossible, for the enemy to determine their flight path: “Even if detected, it is not possible to determine a cruise missile’s target with certainty,” concluded a scientific paper published in 1992 — long before hypersonic weapons assumed a front row seat in military procurement debates.
To be sure, at least some proponents of hypersonic arms control acknowledge that the ambiguity risks associated with hypersonic missiles apply equally to ballistic missiles and subsonic cruise missiles. Yet, they also argue that warhead and target ambiguity are aggravated by the high speeds of hypersonic weapons, which reduces the response time for decision-makers. But this assessment overstates decision-makers’ response time to attacks with subsonic cruise missiles. Due to their small radar cross-section as well as their low sound and heat signatures, subsonic cruise missiles are intrinsically stealthy, thus making them incredibly hard to detect and defend against. It is thus far from obvious whether the employment of hypersonic missiles would actually compound existing risks of inadvertent escalation, let alone bring about new ones.
Bringing Back the Operational Context
Another issue is that the escalation risks of hypersonic weapons are usually analyzed in a fairly abstract fashion that is disconnected from how and in which context these weapons would actually be employed in a conflict. This has led to an undue focus on the technical characteristics of certain weapon systems while distracting from perhaps the most serious risk of nuclear escalation associated with hypersonic weapons — their use by the U.S. military against Russia or China in conjunction with more traditional long-range strike capabilities.
Conventional long-range precision strike weapons are a major concern to both Russia and China, and for good reason. In a potential war with China, for example, the United States military would likely attack hundreds, if not thousands, of ground targets on the Chinese mainland to disable China’s extensive anti-access/area denial networks. In such a strike campaign, hypersonic weapons would have a role to play, especially against a set of time-sensitive, relocatable targets such as mobile missile launchers. For most missions, however, simple cruise missiles would do the job.
Given the scale of such a campaign, U.S. military operations would almost certainly erode important components of China’s nuclear capabilities, regardless of whether this was a U.S. objective or not. The issue of target ambiguity is therefore mostly academic and unlikely to play a role in a real military conflict where nuclear-relevant infrastructure, in all probability, will be targeted. Chinese nuclear escalation would be a major risk, but what it would come down to eventually is how the Chinese leadership would assess the nature of the U.S. campaign — that is, if it believed the United States was engaging in conventional counterforce — and not on the technical characteristics of a particular weapon system.
The risk of nuclear escalation would loom equally large in a direct military conflict between Russia and the United States. As Michael Kofman has written in these pages, Russia considers various strategic defensive systems such as command-and-control nodes, strategic radars, and other critical infrastructure as vital for the functioning of the state and its nuclear command and control. Should a prolonged U.S. strike campaign destroy or degrade these systems and Russia find itself unable to counter incoming attacks — for example, due to the functional defeat of its air defense networks — there would be few options left for the Russian military beyond the employment of nuclear weapons in theater.
Yet again, the risk of nuclear escalation is barely related to hypersonic weapons. It is first and foremost a result of the way the U.S. military would operate in a conflict, which can be found in the current, theater-agnostic U.S. Joint Concept for Access and Maneuver in the Global Commons, the successor of a once-controversial concept that focused solely on the Indo-Pacific. Although the warfighting concept no longer envisages the “disrupt, destroy, defeat” approach of Air-Sea Battle, it is highly likely that the U.S. military would still attempt to strike its adversaries’ command, control, communications, computers, intelligence, surveillance, and reconnaissance networks to establish freedom of action. Therefore, the idea that Russian decision-makers might monitor a bunch of incoming hypersonic missiles, falsely assess that nuclear command-and-control facilities are being targeted, and then inadvertently engage in nuclear counter-escalation is just not a serious one.
Finally, it is important to note that escalation risks are not created equal. While a U.S. strike campaign in a potential war with Russia or China would be directed against Russian or Chinese territory, Russia and China would be more likely to use their hypersonic weapons against U.S. overseas military bases and U.S. allies in Europe or the Indo-Pacific. In other words, whereas the stakes might quickly become existential for Russia or China, they would not for the United States — Russia and China would face much greater incentives to escalate to the nuclear level. The geopolitical and strategic context matters a great deal, a point that is often lost in contemporary arms control debates.
A Different Approach to Hypersonic Arms Control
Many experts would consider hypersonic weapons as overhyped, and the same holds true for the escalation risks commonly associated with them. There are, in fact, hardly any attributes specific to hypersonic weapons that would introduce truly new escalation risks in a potential military conflict. Both warhead and target ambiguity, which have consumed most of the attention in the debate about hypersonic weapons, have existed for several decades and apply equally to other missile and delivery systems. Meanwhile, there has not been enough attention on how U.S. concepts of military operations, which encompass but do not rely on the employment of hypersonic weapons, can lead to nuclear escalation.
If hypersonic missiles are not the real problem but the current U.S. warfighting concept is, then the most promising avenue for arms control is not regulating weapons but changing the warfighting concept. Such an approach might be somewhat counterintuitive — for arms control is usually considered to take the form of formal treaties that set quantitative or qualitative constraints to certain types of armament. However, arms control can take many different forms, and effective arms control does not necessarily have to be a negotiated, legally binding international agreement.
In recent years, numerous experts have proposed alternative warfighting concepts and strategies to the dominant U.S. mode of military operations. Some of them include offshore control, defensive defense, and the aforementioned “spider in the web” approach. These warfighting concepts and military strategies are tailored to the Info-Pacific theater, and there are major differences between them. Yet, what they all have in common is that they do not rely on strikes or military operations on the adversary’s territory, usually call for building up U.S. allies’ own anti-access/area denial capabilities, and thus considerably reduce the risk of nuclear escalation. Over a decade ago, T.X. Hammes outlined an offshore control strategy that would effectively enforce a distant blockade on China without escalating to nuclear war. Similarly, the “spider in the web” approach, which was designed for the European theater, would eschew potentially escalatory deep strikes on targets in Russian territory and offensive maneuver warfare that may well cross the border between Russia and NATO due to the geographically narrow operational area in the Baltics.
Arms control analysts would do well to pay more attention to how and in which context certain weapons would be employed by the military, rather than focusing too narrowly on the technical characteristics of these weapons. No doubt, changes to U.S. military doctrine and strategy will not happen overnight and may be difficult to achieve. It is also true that no strategy is entirely risk-free — even a maritime blockade against China may lead to escalation. Nevertheless, engaging in these sorts of discussions could eventually prove more worthwhile to address the risks of nuclear escalation than trying to regulate every fancy weapon system that is currently under development.
Frank Kuhn is a doctoral researcher at Peace Research Institute Frankfurt and project coordinator for the Cluster for Natural and Technical Science Arms Control Research. His research interests include nuclear deterrence, arms control and nonproliferation, military technology, and military strategy. The views expressed in this article represent those of the author alone.
Image: U.S. Air Force photo by Staff Sgt. Pedro Tenorio
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