The centerpiece of this issue is a collection of articles resulting from a project undertaken by research staff members of the Royal United Services Institute (RUSI) and the James Martin Center for Nonproliferation Studies (CNS) with the support of the Carnegie Corporation of New York. This study explores the consequences of the proliferation of long-range conventional precision-strike technology to certain countries—namely, those that do not possess nuclear weapons but have one or more nuclear-armed allies or partners and one or more nuclear-armed would-be adversaries.
This topic occupies a special niche within a burgeoning field of study: the effects of “emerging” technologies on strategic stability. Unlike artificial intelligence, drone swarms, or quantum computing, precision strike is not a novel or experimental set of techniques; its present state of “emergence” is found instead in its dissemination across international boundaries. No longer do leading military powers such as the United States, Russia, and China have a near-monopoly on these weapons, which are now spreading rapidly across Asia and Europe.
To gain an initial understanding of the implications of this trend for strategic stability, RUSI and CNS researchers examined countries “under the nuclear umbrella”—that is, those countries that rely explicitly or implicitly on an ally’s “extended” nuclear deterrence to contend with potential nuclear threats. In practice, this category currently involves treaty allies of the United States—through either bilateral treaties or the NATO alliance—and certain countries indirectly linked to NATO through membership in the European Union.
The traditional concerns of extended deterrence center on geopolitics and nonproliferation: if a recipient state finds itself insufficiently “assured,” its leaders might either seek accommodation with an adversary or set out to acquire a nuclear arsenal of their own. But acquiring long-range conventional strike capabilities has begun to alter the relationships of these countries with their nuclear-armed allies and to shift their own position within the complications of nuclear policy. Strategic stability has entered the picture.
Defense policy makers in nuclear-armed states tend to appreciate that their own conventional precision-strike weapons increasingly may pose a threat to an adversary’s nuclear forces, command-and-control systems, or leadership, either in conjunction with their nuclear forces or by themselves. In this context, precision strikes are already understood as a potential tool of preemption. Their influence on strategic stability—especially upon the incentives to use nuclear weapons during a crisis or a conventional conflict—is debated accordingly.
Depending on the details of geography and technology, this observation now applies as well to the conventional precision-strike capabilities in the possession of non-nuclear-armed states. Not only are these countries gradually becoming able to pose threats to adversaries’ nuclear forces, or parts of them, but they do so as independent centers of decision. The growing availability of these technologies means that some of the same perils once associated with nuclear proliferation within the NATO alliance, or with the pre-delegation of nuclear release authority within a single country, are emerging in a new guise. Even as the proliferation of nuclear weapons themselves seems to be largely held in check, the power to spark a nuclear war is spreading.
Joshua H. Pollack, Cristina Varriale, and Tom Plant provide theoretical grounding for the role of a third party without nuclear weapons in strategic stability, analyzing the temptations of conventional counterforce and the potential pathways to nuclear use that result. They also report on the perspectives of officials and experts in six countries currently acquiring or debating the merits of precision-strike capabilities: Poland, Germany, Sweden, Finland, South Korea, and Japan.
Justin Bronk assesses the specific technological trends associated with conventional precision strikes: stealthy platforms, hypersonic cruise missiles and hypersonic glide vehicles, sensor fusion, and directed-energy weapons. As each technology advances, it aids the ability to locate and strike targets, the ability to protect them, or both. The ultimate implications for strategic stability may depend on the relative success of these different technologies.
Łukasz Kulesa reviews the record of Poland’s acquisition of long-range conventional strike capabilities since 2013. He describes a process of “maturation and rationalization” that has moderated early ambitions in Warsaw for a non-nuclear “strategic deterrent” against potential Russian aggression. Today’s approach is grounded in a recognition of the limits imposed by Poland’s dependence on NATO for long-range intelligence, surveillance, and reconnaissance (ISR) capabilities, but the acquisition of new weapons and platforms continues regardless.
Charly Salonius-Pasternak compares the cases of Finland and Sweden, two EU members outside of the NATO alliance but indirectly associated with it. Each country formally considers itself to be self-reliant for national defense but could not reasonably expect to forgo help in all circumstances. Finland, which shares a long border with Russia, indicated plans to acquire long-range strike capabilities starting in 2004. It has now begun to integrate American-made air-to-ground missiles into its arsenal, while enhancing interoperability with NATO forces. Only after the start of Russia’s war in Ukraine in 2014 has Sweden set out to pursue similar goals, seeking to “raise the threshold” for an adversary to launch an attack on its territory.
Joshua H. Pollack and Minji Kim examine South Korea’s simultaneous pursuit of long-range conventional strike capabilities and full operational control of its own armed forces. South Korea has built a well-developed arsenal of both indigenous and imported precision weapons, with the openly stated purpose of achieving the ability to attack and disarm North Korean nuclear forces. Budget constraints and continued dependence on American ISR limit the effectiveness of these new capabilities but would not prevent Seoul from using them.
Dmitry Stefanovich assesses Russia’s understanding of the rise of “national reconnaissance-strike” capabilities around its periphery, a problem potentially aggravated by the demise of arms-control arrangements in Europe. Russian experts have often compared the military effects of these systems to those of nuclear weapons, and officials have expressed special concern about Poland’s acquisition of extended-range air-to-surface missiles. While Russian experts note the continued shortcomings of ISR among neighboring states, the military is devoting growing attention to countermeasures, including improved missile defenses, new radars, electronic warfare, decoys, and concealment.
Tong Zhao addresses the potential for long-range conventional weapons to undermine China’s nuclear deterrent, which remains significantly smaller than Russia’s, or to contribute to escalation, whether intentional or inadvertent. In Beijing, capabilities developed by the United States and its regional allies to contend with threats from North Korea are often perceived as being aimed at China, or at least bearing upon its security. Japanese debates about acquiring long-range strike capabilities have attracted particular concern. Allied contributions to US missile-defense capabilities and anti-submarine warfare are also seen as threatening China’s ability to sustain its nuclear deterrent. These problems feed into concerns about strategic stability in a broader sense—not only the problems of nuclear deterrence and arms racing, but the ability to protect China against the threat of foreign military intervention.
David Blagden presents a nuanced case for relative optimism about the spread of conventional precision-strike capabilities. Examining Poland as a case study, he observes that long-range conventional strike assets should enhance aspects of deterrence, thereby reducing pressure on extended-deterrence commitments from nuclear-armed allies. Yet by the same token, problems in realizing the full potential of these systems, notably the lack of sufficient ISR, could lead to a failure to strengthen deterrence while still exacerbating political tensions. The net outcome also depends on the scale of acquisitions: if too small and weak, they would not provide deterrence benefits; if too large and capable, they could undermine strategic stability. The resulting picture is ambiguous, and unlikely to produce uniform results from country to country.
A concluding commentary from UN High Representative for Disarmament Affairs Izumi Nakamitsu emphasizes the risk that growing conventional threats to nuclear arsenals will present a new obstacle to the pursuit of further reductions in nuclear forces. This development, alongside the trend of dismantling arms-control agreements and the “protracted deadlock” in multilateral disarmament bodies, would contribute to further deterioration of the international-security environment. In recent decades, attempts at controlling the spread of missiles have fallen short of their goals. Renewed efforts are needed now, whether in the context of bilateral strategic arms reductions or multilateral missile controls.