Extended Nuclear Deterrence in Northeast Asia

NAPSNet Special Report

Recommended Citation

Jeffrey Lewis, "Extended Nuclear Deterrence in Northeast Asia", NAPSNet Special Reports, August 01, 2012, https://nautilus.org/napsnet/napsnet-special-reports/extended-nuclear-deterrence-in-northeast-asia/

by Jeffrey Lewis

August 1, 2012

A version of this report was originally presented at the East Asia Nuclear Security workshop held on November 11, 2011 in Tokyo, Japan. All of the papers and presentations given at the workshop are available here, along with the full agenda, participant list and a workshop photo gallery.

Nautilus invites your contributions to this forum, including any responses to this report.


I. Introduction
II. Report by Jeffrey Lewis
III. References
IV. Nautilus invites your responses

I. Introduction

Jeffrey Lewis argues that US allies such as Japan have been mislead by the manner in which past administrations have sought to emphasize the strength of their extended deterrence commitments by reference to particular weapons systems in that role. Lewis writes that “there is no specific commitment to use any of those nuclear weapons in defense of Japan – or any other ally.”

Rather, Lewis states, “it is time to be honest that the primary source of nuclear deterrence for US allies comes from the strategic triad of intercontinental ballistic missiles, submarine launched ballistic missiles and bombers.” He concludes that “US nuclear weapons continue to play role, albeit a declining one, in meeting US security commitments. The US is committed to defending Japan, but the use of nuclear weapons neither necessary nor desirable in the current strategic environment.”

Jeffrey Lewis is an Adjunct Professor and Director of the East Asia Non-Proliferation Program at the Monterey Institute of International Studies.

The views expressed in this report 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 significant topics in order to identify common ground.

II. Report 

Extended Nuclear Deterrence in Northeast Asia
by Jeffrey Lewis

The place to start any discussion about the future of extended deterrence—which is essentially an American phenomenon—is with a heresy: There is no such thing as the “nuclear umbrella.”

Of course, the United States has security commitments to many countries in Northeast Asia.  For example, the 1960 Treaty of Mutual Cooperation and Security between the United States and Japan commits the parties to “act to meet the common danger” from an “armed attack against either Party in the territories under the administration of Japan.”  And, of course, the United States also possesses an arsenal of nuclear weapons second to none that could be used in response to such an attack.

But there is no specific commitment to use any of those nuclear weapons in defense of Japan – or any other ally.  Neither the US-Japan agreement nor any other US defense agreement commits the United States to use nuclear weapons in any specific scenario.  The “nuclear umbrella” is, at best, an implication of the US defense commitments.   It is, in certain cases, an unavoidable implication. But the important observation is that extended nuclear deterrence is something that arises from the day-to-day practice of alliance defense cooperation and alliance management.  The United States and its allies must continually engage in a process that credibly links security commitments to available nuclear forces.

Much of the history of extended deterrence is best understood as an ongoing process to make real the commitment implied by the dual reality of US security commitments and the existence of US nuclear weapons.  In Europe, this process took the form of planning activities and “nuclear sharing” arrangements in which European pilots in so-called “dual capable” aircraft trained to drop American nuclear bombs.  In Japan (before 1972) and South Korea (before 1991), the commitment was implied by US nuclear weapons stationed on their territories.  Yet the weapons themselves were largely peripheral to fundamental questions about credibility that were essentially political.  South Korea, for example, began a nuclear weapons program in the late 1970s in response to concerns that the United States might not defend a regime it viewed as repressive.  Although discussions about the withdrawal of ground forces and nuclear weapons certainly alarmed South Korea’s military governments, South Korea’s interest in nuclear weapons continued even after the Reagan Administration made plain that it intended to leave US troops and nuclear weapons in South Korea.

With the withdrawal of US nuclear weapons from South Korea in 1991, there are no US nuclear weapons forward deployed in the Asia-Pacific region.  In Northeast Asia, the United States faces a special challenge in demonstrating the credibility of extended deterrence, conventional and nuclear. North Korea, in particular, seems to regard its small nuclear arsenal as a short of shield from behind which it can initiate limited offensive military operations against South Korea.  The sinking of the Cheonan and the shelling of Yeonpyeong Island demonstrate to the United States the continuing security challenges that give rise to demands for extended deterrence.

Since the withdrawal of the last forward deployed nuclear weapons from Northeast Asia in 1991, American officials have largely emphasized specific systems and capabilities in the American arsenal that are said to be maintained for the unique task of extended deterrence, on the grounds that defense expenditures demonstrate a seriousness of purpose. So, for example, in 2001, the Bush Administration told Japan that the United States was retaining the option to deploy nuclear-armed Tomahawk missiles (which were sitting in storage) on US attack submarines just to show we were serious about defending Japan.

The problem with this approach is that US conventional and nuclear capabilities continue to evolve.  Relying on specific instances of military hardware to demonstrate the US commitment in essence commits the United States to maintain those capabilities long past their obsolescence. The United States would not, under any conceivable circumstance, have redeployed the nuclear-armed Tomahawk missile.  All along, the Navy intended to retire the system in 2013 and made few efforts to replace it.  In 2010, the Obama Administration had to choose between explaining to Tokyo that American officials hadn’t been entirely frank in 2002 about the role that nuclear-armed cruise missiles played in Japanese security – or spending money the Navy didn’t have to maintain and replace a system that would remain in storage. Fortunately, the Obama Administration decided to proceed with the retirement of the nuclear Tomahawk.

The Obama Administration calculated, correctly in my view, that consultations were much more important than the nuclear Tomahawk.  One result of the Nuclear Posture Review process has been much more significant consultations with US allies, especially Japan and South Korea.  Japan and the United States began an “Extended Deterrence Dialogue” with the Nuclear Posture Review, which the two parties agreed to continue in June 2011.[1] (The most recent meeting was held at US Strategic Command in Omaha in early 2012.) Similarly, the United States and South Korea have established an “Extended Deterrence Policy Committee” that helps provide some of the same consultation functions that exist in NATO.  The consultations tend to occur at the Deputy-Assistant and Assistant Secretary-level, with a high-level focus on policy matters.  These discussions do not replicate the detail of the NATO Nuclear Planning Group, in part because decisions relating to the use of nuclear weapons do not involve Japanese or South Korean forces.

Unfortunately, the 2010 Nuclear Posture Review also continued the short-sighted practice of emphasizing hardware as a proxy for the “nuclear umbrella.”  This time, the United States asserted that the US commitment to extended deterrence was demonstrated by the effort to make nuclear-capable the Joint Strike Fighter (and extend the life of the B61 nuclear gravity bomb it would carry) and the ability to forward deploy US bombers, like the B-2, particularly in Guam.

These are, however, irrelevant capabilities that may not survive the current budget austerity. There are no military missions for the B61s deployed in Europe   — one NATO official admitted to me that “we would never drop a B61 off the wing of an airplane” — and the Air Force does not want to spend the money on giving the JSF an obsolete nuclear capability. (Nor do our European partners seem keen to modernize their own “dual capable” aircraft.) Nor would the United States forward deploy nuclear-armed B-2s, either in Guam or elsewhere.  The B-2 can reach targets from North Korea to Iran directly from Missouri, which is what the United States did in the early stages of operations against Yugoslavia, Afghanistan and Iraq.  The only rationale for forward-basing is to permit more sorties – something of interest only in ongoing conventional operations.

Although the United States certainly has a list of targets in North Korea that might be subject to nuclear attack, it is unlikely that the US plans to use nuclear weapons against North Korea, any more than it used those weapons against Iraq in 1991 or 2003.  According to press reports, the major plan for defending South Korea, OPLAN 5027, is conventional-only, with a “counter-nuclear” option.[2] Three recent events may help explain why this may be the case.  First, the United States realigned its forces in South Korea, pulling US troops away from the DMZ.  Although some observers interpreted this as a reduction in capability, those forces were actually removed from static defensive positions in favor of basing that would permit rapid deployment in an offensive against Pyongyang. Second, the Commander of USFK Special Operations recently state that, in the event of a conflict, the United States would operate Special Forces units behind North Korean lines. Finally, satellite images and other sources suggest that the Korean People’s Army appears to be emplacing static defenses to absorb a rapid thrust of US and South Korea forces in the event of hostilities. These developments all suggest that the most likely for scenario is no longer a North Korean reprise of its 1950 invasion of the South, but rather a US and ROK offensive that begins before North Korea can mobilize for an attack.  The United States is unlikely to use nuclear weapons ahead of advancing US and ROK military forces.

The Obama Administration is already considering ways to save on the F-35, having reduced the number of aircraft to be purchased by one-third.  Some officials have proposed eliminating the nuclear capability for the fighter as a further cost-saving measure.  The possibility that Congress could kill the entire F-35 program remains unlikely, but is no longer unthinkable. Similarly, the lifetime extension program for the B61 is facing significant cost growth and program delays. There is simply no guarantee that the capability to forward deploy nuclear-capable fighter aircraft will survive the current budget environment.

Other senior officials, including the Secretary of Defense and Chairman of the Joint Chiefs of Staff, have openly questioned the strategic triad, leading some analysts to conclude that the bomber leg will not survive indefinitely.  The United States has already announced significant reductions in defense spending over the next decade, with additional cuts to follow if a budget agreement is not reached.  If Congress and the President fail to reach a budget agreement, a second round of across-the-board cuts, will occur.  (This process is called “sequestration.”)  The US Secretary of Defense, Leon Panetta, has warned that sequestration could include the following steps:

  • Terminate the Joint Strike Fighter; minimal life extensions and upgrades to existing forces ($80B);
  • Terminate the bomber leg of the triad; restart new program in mid 2020s ($18B);
  • Delay the next generation ballistic missile submarine; cut force to 10 submarines ($7B);
  • Eliminate ICBM leg of the triad ($8B).

Even without the blunt instrument of sequestration, this Administration or the next may end up explaining that the 2010 Nuclear Posture Review, in its own way, was not entirely frank about the importance of the F-35 and the B2 to Japanese security.

In this current environment, it is time to be honest that the primary source of nuclear deterrence for US allies comes from the strategic triad of intercontinental ballistic missiles, submarine launched ballistic missiles and bombers.  In the foreseeable future, the United States will be focused on maintaining these capabilities — either as a triad or dyad — while shedding theater capabilities like the nuclear Tomahawk and nuclear-armed fighter aircraft.  Budget pressures in the United States are now leading to intense scrutiny.  The United States is about to invest significant amounts to replace its fleet of US ballistic missile submarines, fighter aircraft and heavy bombers.   The next Administration will face difficult choices about which capabilities represent good value.  In such an environment, the United States should spend to optimize its ability to credibly provide security, with consultations providing an important means for allies to convey their assessment of the threat and the United States to demonstrate how it can meet the threats to their security.

US nuclear weapons continue to play role, albeit a declining one, in meeting US security commitments. The US is committed to defending Japan, but the use of nuclear weapons neither necessary nor desirable in the current strategic environment. Although US policymakers believe that some ambiguity about nuclear options remains valuable, the United States and Japan would respond with conventional forces in all plausible circumstances. Nevertheless, the United States relies on the capabilities inherent in the “central strategic forces” of the US provide a basic measure of deterrence for the homeland, our forces abroad and our allies in the unlikely event of a nuclear attack. Generally speaking, the capabilities embedded in the strategic triad should also provide a similar level of deterrence to our allies and partners in Northeast Asia.  The United States and Japan have a political challenge rather than a military one – how to demonstrate that the United States is as committed to the defense of Seoul and Tokyo as it would be defending Seattle and Tacoma. This argument needs to be rooted in shared interests and values, which endure, rather than specific military systems, which will continue to evolve.

Ultimately, consultations will be the most important tool.  The formal dialogues initiated by the Obama Administration are an important and necessary mechanism. The policy challenge is now to utilize those mechanisms to ensure a regular consultation on working-level issues with policy implications, such as the development of common rules of engagement for missile defense systems developed cooperatively. The dialogues remain limited by the terms of the United States Atomic Energy Act (AEA), which governs the exchange of nuclear-related information. The United States, for various reasons, does not have legal agreements with Japan or South Korea that would permit exchanges comparable to NATO under the Agreement between the Parties to the North Atlantic Treaty for Co-operation Regarding Atomic Information.

During the Cold War, for example, the US emphasized the formal commitment of US strategic capabilities — ballistic missile submarines and missile warheads to NATO. The United States might propose a number of measures to help Japanese and South Korean officials better understand the role of strategic assets in their security.

Such consultations could be supplemented by displays, such as port visits by ballistic missile submarines.  The United States also used visits by US ballistic missile submarines to visibly demonstrate US commitment, including an unusual period in the late 1970s when dozens of US ballistic missile submarines made port calls in South Korea.[3] If the allies seek a visible indication of the US commitment, that role could be fulfilled by visits of Ohio-class submarines.

Such visits would need to be carefully considered in the context of a Nuclear Weapons Free Zone. Although the United States would not agree in principle to any zone that might be understood as limited freedom of navigation for nuclear-armed vessels, in practice the United States may wish to avoid acting in a manner that is inconsistent with the spirit of a nuclear weapons free Northeast Asia.[4]   For any signatory to a Nuclear Weapons Free Zone, or event countries like Japan where sensitivity to US nuclear weapons deployments is high, the United States could arrange for visits by Guided Missile Submarines (SSGNs) – converted ballistic missile submarines that no longer carry nuclear weapons.  These ships, constrained as they are by treaty limits, are the sole naval exception of the US policy of neither confirming nor denying the presence of nuclear weapons aboard a specific naval vessel.  They simultaneously signal the United States to its allies in Northeast Asia and, as platforms converted to conventional use, the declining role of nuclear weapons.

The United States might provide for Japanese liaison officers to serve at US Strategic Command (STRATCOM).  The goal of such efforts would be to ensure that Japanese and South Korean military officers have detailed and accurate views of the role of nuclear weapons in their security, in addition to formal mechanisms to convey their assessment of the security environment and views about defense choices. Denmark, for example, sends a liaison officer to STRATCOM.[5]  Why not Japan?  The liaison officer could serve in a non-nuclear field, such as cyber-security, if necessary.  The purpose of such an exchange would be to provide foreign military officers with a broader picture of the role of STRATCOM and more general US notions of deterrence that are no longer linked solely to nuclear forces.

It is important to note that such consultations are not intended to convince South Korea or Japan that nuclear weapons are an all-purpose deterrent.  Quite the contrary.  As noted before, a realistic assessment of US military capabilities will note that nuclear weapons play a smaller role than ever and would only be considered in the most extreme circumstances.  A realistic assessment of allied capabilities would emphasize the role of conventional forces, including missile defenses, much more than nuclear weapons.

III. References

[1] Joint Statement of the U.S.-Japan Security Consultative Committee, June 21, 2011.  Available at: http://www.state.gov/r/pa/prs/ps/2011/06/166597.htm

[2] “Seoul Moves to Enhance Nuclear Deterrence,” The Korea Herald, October 13, 2006.

[3] Many declassified documents concerning the program of SSBN visits are available at: Hans Kristensen, “When the Boomers Went to South Korea,” FAS Strategic Security Blog, October 4, 2011. Available at: http://www.fas.org/blog/ssp/2011/10/ssbnrok.php

[4] The United States expressed concern about the limited restrictions on transit in the Southeast Asia Nuclear Weapons free zone, which merely reserved the right of a state party to “decide for itself” whether to permit transit of nuclear-armed vessels in cases other than innocent passage, archipelagic sea-lanes passage, or transit passage.

[5] The Memorandum of Understanding for the Danish liaison officer is available at: http://www.state.gov/documents/organization/70918.pdf

IV. Nautilus invites your responses

The Nautilus Peace and Security Network invites your responses to this report. Please leave a comment below or send your response to: napsnet@nautilus.org. Comments will only be posted if they include the author’s name and affiliation.

4 thoughts on “Extended Nuclear Deterrence in Northeast Asia

  1. Jeffrey Lewis’ analysis of extended deterrence in Northeast Asia is a breath of fresh air. It sensibly lays out a realistic picture of what the United States would be prepared to do in the event of aggression against South Korea or Japan. Collective security or common security has historically focused on the relationships among governments, and not, as Lewis rightly points out, on the weapons systems to be used. Lewis’ argument could also be applied to relationships within NATO and the nuclear weapons still remaining in Europe. Security is not based on nuclear weapons—never has been, never will be. Thanks for making the argument so plainly.

    Kennette Benedict, PhD
    Executive Director

    Bulletin of the Atomic Scientists

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