Is It Time for Nuclear Sharing in East Asia?


It was reported recently that back in May, South Korea eyed shared control of nuclear weapons with the United States. This has been a long time coming — first, because there are now increasingly severe strains on the credibility of U.S. extended deterrence in the Asia-Pacific, and second because for the first time in history, U.S. extended nuclear deterrence faces severe challenges in both Europe and the Asia-Pacific.

In Europe, Russia is presenting an increasing challenge to NATO. With its recent incursion into Ukraine, NATO’s weaker military forces, and Moscow’s signaling of a “de-escalatory” nuclear strike in response to, for example, a NATO offensive to recapture a potential Russian-occupied Baltics, NATO’s nuclear posture may need to change. Indeed, how might Washington respond to a Russian de-escalatory nuclear explosion? With limited nuclear strikes in return? One option would be for NATO partners to wield a retaliatory option themselves, since it is not entirely clear that Washington would be ready to launch large-scale nuclear counterforce strikes against Russian forces in a “Baltic” scenario. Compared to other U.S. nuclear adversaries, Russia may have too many nuclear weapons to be targeted by comprehensive counterforce strikes.

The upgraded B61s, stockpiled in Germany and Western Europe, and under U.S. authority, may not be sufficient to deter a Russian de-escalatory nuclear attack. This might be problematic, because the U.S. president would then have to authorize the use of these weapons stockpiled in Europe. Moreover, the range of the Dual-Capable Aircraft (DCA) may not be long enough (refueling is prone to fail in contested airspace), and there might not be sufficient warheads at NATO’s disposal. Instead, the United States could decide on a limited counter value strike. These could be executed by NATO members with a greater authority in nuclear use.

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It is also time for U.S. allies in Asia to become much more involved in the U.S. nuclear targeting and employment planning processes. Faced with increasing Chinese and North Korean military power, Japan, South Korea, and even Australia are making greater investments in bigger military hardware, including submarines. To some extent this reflects unease about U.S. resolve. Such unease may lead to a downward spiral of increased mistrust and tensions in the region, which is disadvantageous to the United States, its allies, and China alike. But that can be redressed in part by including Seoul, Tokyo, and Canberra in a dialogue that goes deeper than the strategic or operational level of nuclear strategy, into the actual decision-making of targeting. Moreover, it would be useful to coordinate the use of conventional forces into this decision-making – integrated command and control.

A major question remains – could this ever be done on a multilateral basis? Many of the issues encountered in the Asia-Pacific today bear resemblance to politico-strategic questions of Cold War Europe. However, the problems of extended deterrence are far bigger in the Asian maritime context than in the European context, it thus becomes even more important for allies to have a say in these issues.

Extended nuclear deterrence has been a central tenet of most of America’s post-World War II alliances. Like during certain moments during the Cold War, that security guarantee is being seriously challenged in both Europe and the Asia-Pacific.  However, extended deterrence in a maritime, multipolar, and non-contiguous maritime environment is a lot harder to achieve than it ever was in a bipolar, contiguous, land context in Europe.

Realizing that U.S. conventional forces may not be sufficient for a protracted conflict between China and the United States, both Seoul and Tokyo have been stepping up their game with an expansion of submarine and land-based missile systems. Aside from allies doing more for their own defense, we might see U.S. nuclear weapons policy evolve. The issue of “friendly proliferation” is an issue that is going to come up more and more in Asia. This prospect might not only make alliance management harder for Washington and evoke unforeseen reactions from Peking, but it would also ruin long-term prospects for regional arms control and disarmament.

The dynamics that generated U.S.-NATO nuclear sharing, and eventually the idea of a Multilateral Nuclear Force (MLF), in Europe in the late 50s seem to be emerging in Asia today. For both political and military reasons, many European leaders sought control over the American nuclear backbone of Europe’s defenses. Come late 1957, the United States responded by proposing tactical atomic stockpiles and IRBMs (Intermediate Range Ballistic Missiles) to NATO Europe: such nuclear sharing had to give Europeans “the feel” of NATO control, while the actual warheads remained under U.S. command and control. In 1966, the NATO nuclear planning group was established. This allowed the European allies to play a role in the decision making process about how and under which circumstances the American weapons would be used.

Chinese military capabilities are increasingly posing a threat to American regional leadership. Meanwhile, American allies are geographically dispersed and have widely diverging interests. This makes it difficult to develop a “one-size-fits-all” approach to the emerging Chinese politico-strategic challenge. In the absence of satisfying new multilateral approaches emanating from Washington, U.S. allies might seek national solutions, including nuclear proliferation or accommodation with Peking. Crucially, this downward spiral might be countenanced by enhancing a nuclear sharing relationship between Washington, Seoul, Tokyo, and Canberra. Expanding the role of nuclear weapons in U.S. diplomacy toward the Asia-Pacific might both improve regional strategic stability, while keeping long-term arms control and disarmament options open.

Absent the United States allowing its allies to “go nuclear,” would something resembling the NATO nuclear sharing schemes devised in response to the challenges of the late 1950s and the 1960s even be possible for Asia? This would imply bilateral dual-key atomic stockpile or ballistic missile arrangements with individual allies, operating under a regional allied command, while remaining under U.S. nuclear control. Although the option of a truly multilaterally controlled nuclear missile force was deferred by NATO, it does remain a hypothetical option in the Asia-Pacific.

The idea of a joint Asian nuclear force was floated during the 1960s. In the aftermath of China’s nuclear test, a multilateral nuclear hardware and control sharing scheme for Asia was mooted in Washington as a way to prevent China’s neighbors from acquiring their own nuclear weapons. Dean Rusk supported this scheme and even voiced support for Japan and India developing their own deterrent capabilities. In parallel, Washington entertained the idea of deploying ICBMs in Australia.

A renewed debate on nuclear sharing in the Asia-Pacific is in order. However, the obstacles are formidable. First, there is much historical distrust and animosity between Japan and South Korea. Second, the regional U.S. allies will have different threat perceptions and ideas about targeting and escalation regarding both North Korea and China. These issues reflect the bigger issue that there is no Asian NATO. The question remains, however, in the long run: at what point will the major allies be unsatisfied with any system of nuclear control that leaves the decision to use nuclear weapons solely in American hands? Arguably, though, nuclear hardware and control sharing would make any future attempts at nuclear and conventional arms control with China much more complicated. This is the potential tricky trade-off between reassuring allies on the one hand, and seeking a “stable” relationship with both China and North Korea on the other.

These issues feed into the bigger issue of developing a coherent maritime doctrine, and giving allies a say in this doctrine, just like with NATO. This will be crucial, because at a certain point nuclear weapons come into calculations about escalation. How can allies “rely” on U.S. extended deterrence if they remain blind to the nuclear aspects of U.S. operational planning?

What all this comes down to is the question of what is the best way to achieve stability in the region? Does this entail introducing tactical nuclear weapons and Intermediate-Range Nuclear Forces on South Korean and Japanese soil? Or establishing joint U.S.-Japanese/U.S.-South Korean control over sea-launched cruise missiles? The essential point remains, that given the increasing relevance of nuclear weapons to U.S. maritime strategy, it might make sense for U.S. allies to be more involved in dialogue and planning.

Elmar Hellendoorn is an independent geopolitical consultant and lecturer at Utrecht University.

Christine M. Leah has served as a postdoctoral fellow at Yale University and MIT.  

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