Rethinking Extended Deterrence in Northeast Asia
Policy Forum 10-054: November 03, 2010
II. Article by Jeffrey Lewis
IV. Nautilus invites your responses
This paper is part of the Nautilus Institute’s Korea-Japan Nuclear Weapon Free Zone Initiative.
Jeffrey Lewis, Director of the Nuclear Strategy and Nonproliferation Initiative at the New America Foundation, writes “Rather than focusing on extended deterrence and nuclear capabilities in particular, I would suggest we think about what might be called “extended defense”—what are the actual capabilities that the United States and its allies in Northeast Asia would procure and deploy to deal with the most urgent threats? These are increasingly missile defenses and antisubmarine warfare capabilities, not nuclear cruise missiles and bomber bases. The excessive focus on nuclear capabilities has stunted the US dialogue with its security partners in Northeast Asia, wrongly placing the emphasis on ephemeral capabilities that will necessarily evolve instead of shared interests and values that will endure.”
The views expressed in this article are those of the author and do not necessarily reflect the official policy or position of the Nautilus Institute. Readers should note that Nautilus seeks a diversity of views and opinions on contentious topics in order to identify common ground.
II. Article by Jeffrey Lewis
-“Rethinking Extended Deterrence in Northeast Asia”
By Jeffrey Lewis
There is a widening, yawning even awesome gap between the rhetoric of traditional nuclear extended deterrence, and the reality of targeting, delivery, detonation, and termination of nuclear war on the Korean Peninsula. Much of the rhetoric about extended deterrence reflects myths about the role and purpose of US nuclear weapons. My goal in this paper is to raise doubts about two of those myths, discuss the realities of nuclear targeting on the Korean Peninsula and then suggest—rather heretically—that too much emphasis on nuclear weapons might be bad for extended deterrence.
The two myths are, first, that there is something called “the nuclear umbrella” and, second, that there are US nuclear forces allocated for missions under that umbrella. There is no such thing as “the nuclear umbrella.” The United States does not have specific commitments to aid allies under nuclear attack, beyond the commitment more generally. Nor does the United States have any obligation to use nuclear weapons in a particular circumstance. Nor are there are no “special” nuclear weapons that exist for the purpose of extended deterrence, as distinct from the central arsenal that deters attacks on the United States.
There is a great deal of misunderstanding on both these points, reinforced by political expediency. One US Administration after the other has told allies what they wish to hear, calculating that a little loose rhetoric is surely less harmful than an anxious ally.
I believe that this has been a short-sighted policy and, over-time, is detrimental to allied security. Allies have been allowed to develop dramatically exaggerated notions of the role that nuclear weapons play in their defense. As I will discuss in the third section of the paper, I believe it is very unlikely that the United States would actually use a nuclear weapon on the Korean Peninsula.
As a result, and this is my concluding observation, the long-term effect of the mistaken emphasis on nuclear weapons has been to generate a steady stream of unnecessary anxiety on the part of American allies as the United States reduces its reliance on nuclear weapons and retires obsolete systems. This anxiety, and short-term efforts to manage it, distract from the truly important shared interests that make credible the US commitment to peace and security in Northeast Asia.
There is no such thing as “The Nuclear Umbrella”
It is easy to see why US allies might believe there is something called the “nuclear umbrella”—since 2006, for example, the US-ROK Security Consultative Communiqués have included the term “nuclear umbrella.”
Yet, there is no legal meaning to this term. It does not refer to a treaty provision or US policy. There is not specific treaty or agreement that obligates the United States to any particular course of action in the event of a nuclear attack.
All of the NPT-nuclear weapons states, including the United States, maintain a general assurance that they will come to the aid of a non-nuclear weapon state attacked or threatened with nuclear weapons. There is no specific commitment to use nuclear weapons in a particular situation.
What does exist are US security commitments, usually in the form of security treaties. The so-called “nuclear umbrella” exists only because the United States is pledged to defend Japan and South Korea and happens to possess nuclear weapons. The rest is left to the imagination.
How to demonstrate that a general commitment to the security of allies translates into a realistic threat that the United States might use nuclear weapons in response to at least some threats has been the principle problem of extended deterrence since the beginning of the Cold War.
The United States has labored mightily to convince allies that its defense commitments extend to the use of nuclear weapons though indirect means, such forward deploying nuclear weapons during the Cold War in Japan (until the revision of Okinawa in 1972) and South Korea (until their withdrawal in 1991). 
In Europe, this assurance also took the form of allied “dual-capable” aircraft, although the United States was not obligated to provide nuclear weapons even in the event of an attack.
There are no “special” nuclear forces for theater missions
With the withdrawal of US nuclear weapons from Japan and Korea, as well as the decision to remove nuclear weapons from US surface ships and attack submarines, the United States no longer maintains any nuclear weapons in Northeast Asia. 
As a result, the United States has sought new ways to communicate that its defense commitment to South Korea and Japan has a nuclear component.
Previous US Administrations have attempted to argue that particular nuclear weapons either “belong” or are “allocated” for particular countries. This can be literal – the maintenance of dual capable aircraft by Germany, Belgium, the Netherlands, and Italy. Or it can be implied by the maintenance of otherwise redundant capabilities, like the nuclear Tomahawk missile or TLAM-N.
This Administration has tried to argue that the decision to make nuclear-capable its new combat aircraft, the F-35, and to refurbish the B61 nuclear gravity bomb are large investments intended solely for the purpose of maintaining extended deterrence. Furthermore, the Administration points to the ability to deploy US heavy bombers in Guam as another tangible sign of its commitment.
This continues a long US practice of pointing to obsolete capabilities as political symbols that are completely divorced from the actual strategic planning. In reality, the US nuclear deterrent for Japan and South Korea is the same as the US nuclear deterrence for New Jersey and South Carolina.
In the very unlikely event that the United States were to use nuclear weapons on the Korean Peninsula, it would not go through the trouble to forward deploy nuclear weapons in Guam, Japan or South Korea. Nor would the United States use nuclear weapons based on ballistic missiles, either at sea or in hardened silos in the Great Plains.
Instead, the United States would most likely use gravity bombs from B2 bombers that would operate out of Whiteman Air Force Base in Missouri. During conventional operations over the former Yugoslavia, Afghanistan, and Iraq, B2 aircraft conducted many sorties operated out of Whiteman Air Force Base and back. (Eventually, the United States forward deployed some B2s to Diego Garcia in the Indian Ocean and an undisclosed forward operating base.) North Korea, at about 6,500 miles from Whiteman Air Force Base, is further than Kosovo, but not quite as far as Afghanistan. There is very little reason that the Air Force would go through the additional trouble of flying nuclear weapons to a forward location when North Korea is in range of US strategic bombers in Missouri.
The United States has, of course, exercised forward deploying B2 bombers to Guam (Polar Lightening). But the resulting mission—4,000 miles to Alaska—demonstrates that the United States is mostly interested in operating the B2 at great distances from its targets.
The United States would probably not use nuclear weapons against North Korea
Since the end of the Cold War, the United States has developed nuclear strike options against countries like North Korea. Yet the reality of this planning is much different than one might suppose.
The most important observation is that the United States would not retaliate against cities, as it did at Hiroshima and Nagasaki. Of course, there is what is called existential deterrence—the threat that arises from the existence of the weapons. Who knows what a President might do in anger? But the practical reality is that, in creating strike passages, US military planners are keenly aware of the laws of war.
The reality is that, in addition to a nuclear use, there would need to be a compelling military rationale. There is, in North Korea, the possibility that some hard and deeply buried targets may be too difficult to destroy with conventional weapons. But it is also possible that many of these targets will be difficult for even nuclear weapons to destroy.
The principle US nuclear weapons for holding hard targets at risk are a pair of gravity bombs—the B83 and the B61 Mod 11. The B61 Mod 11 is an earth penetrating weapon, which digs a few feet into the ground in order to couple the explosion to the earth and send a shockwave that could crush a nearby bunker. The effectiveness of such a weapon depends greatly not merely on the hardness of the target, but also the proximity of the explosion.
As a result, the accuracy of intelligence continues to be an issue. The United States is not very likely to have that sort of intelligence in North Korea. As Lt. General Patrick Hughes, then-Director of DIA, explained in the late 1990s, North Korea is “just a real hard target” for intelligence gathering. That is precisely the kind of “hard target” that nuclear earth penetrators cannot destroy.
Moreover, earth penetrators tend to be extremely large, in order to generate enough shock to crush the bunker. The B83 is a one-megaton nuclear weapon, while the B61 Mod 11 is several hundred kilotons. Far from being “mininukes’ or “low yield,” these are among the largest nuclear weapons in the US arsenal and their use would create a significant amount of fallout.
As a result, it appears quite unlikely that, in the event of a nuclear use on the Korean peninsula, that the United States would actually execute a strike package that included nuclear weapons. An interesting parallel is the 1991 Gulf War, when the Bush Administration examined, then rejected, options involving nuclear weapons. As General Charles Horner, who command US Air Forces in the war later explained, “I came to the realization that nuclear weapons had very little utility during the Gulf War, when I realized that even if Saddam Hussein used a nuclear weapon on us, we would have to retaliate on a conventional basis.”
Focus on Extended Defense, Rather than Extended Deterrence
Yet, the United States has continued to argue that nuclear weapons capabilities are an important element of the US defense commitment to Northeast Asia. Why?
One reason is a fear of proliferation. US policymakers have long worried that Japan or South Korea might feel compelled to develop their own nuclear weapons. As a result, there is an effort to try to demonstrate that the US defense commitment, including US nuclear weapons, obviates independent Japanese and Korean nuclear arsenals.
This creates practical problems of how to demonstrate that the US defense commitment is nuclear in character.
Initially, this was done with the forward basing of US nuclear weapons. As local opposition to US nuclear weapons resulted in the eventually withdrawal of US nuclear weapons from Northeast Asia, US policymakers in both Democratic and Republican Administrations have pointed to specific weapons systems that are “allocated’ for Asian missions.
I believe that this has been a mistake. Not only does it not accurately reflect US nuclear weapons planning, I believe this policy results in long-term anxiety. US allies are told a weapon, like the nuclear Tomahawk, is crucial to extended deterrence in Northeast Asia, only to then be told it is obsolete. This anxiety, and short-term efforts to manage it, distract from the truly important shared interests that make credible the US commitment to peace and security in Northeast Asia. Rather than focusing on extended deterrence and nuclear capabilities in particular, I would suggest we think about what might be called “extended defense”—what are the actual capabilities that the United States and its allies in Northeast Asia would procure and deploy to deal with the most urgent threats? These are increasingly missile defenses and antisubmarine warfare capabilities, not nuclear cruise missiles and bomber bases.
The excessive focus on nuclear capabilities has stunted the US dialogue with its security partners in Northeast Asia, wrongly placing the emphasis on ephemeral capabilities that will necessarily evolve instead of shared interests and values that will endure.
 On the role of US nuclear weapons in Korea, see, Peter Hayes, Pacific Powderkeg: American Nuclear Dilemmas in Korea, (Lexington, MA: Lexington Books, 1991).
 United States Pacific Command, Command History 1991, Vol. 1, pp. 90-92, available at http://nautilus.org/wp-content/uploads/2011/12/koreawithdrawal.pdf
(searched date: 30 September 2010).
 United States Department of Defense, “Report of the Secretary of Defense Task Force on DoD Nuclear Weapons Management. Phase II: Review of the DoD Nuclear Mission,” (December 2008), pp. 8, available at http://www.defense.gov/pubs/pdfs/PhaseIIReportFinal.pdf
(searched date: 30 September 2010).
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