The concept of deterrence, let alone that of extended deterrence,
needs to be redefined in a new light. Reducing the role of nuclear weapons in deterrence
strategy should be pursued for the sake of nuclear disarmament.
However, from the perspective of an American ally in Northeast Asia, the proposed
“rethinking of extended deterrence” must be addressed in a much broader
security context than the “conceptual framework” Scott Sagan proposes
in his stimulating article, “Shared Responsibilities for Nuclear Disarmament.”
At the very least, consideration must be given to (1) the regional security conditions
surrounding alliances, (2) the present level of strategic consultations within alliances,
and (3) the long-term prospects of the changing strategic balance between the United
States and its allies, on one side, and its strategic rivals, on the other.
This underlines the importance of a regional rather than a global approach to rethinking
extended deterrence, for, on all these subjects, the tasks and priorities for U.S.
alliances in Northeast Asia are different, for example, from those for NATO. In
contrast to Europe, where the end of the Cold War has remarkably reduced the threat
of nuclear weapons, Asia has been witnessing nuclear weapons proliferation during
the past two decades.
For Japan and South Korea, deterring North Korean aggression while pursuing the
goal of a nuclear-free Korean Peninsula is the top security requirement at present.
U.S. extended deterrence is essential to that end. The
U.S. government has long been firm in assuring its Asian allies of its commitment
to deterrence, and President Barack Obama’s assurances have been unequivocal.
In a speech during his first official visit to Tokyo in November 2009, President
Obama stated: “So long as these [nuclear] weapons exist, the United States
will maintain a strong and effective nuclear deterrent that guarantees the defense
of our allies—including South Korea and Japan.”1
What is equally important for the credibility of the U.S. commitment
is not now to change the U.S. declaratory deterrence strategy. No-first-use arguments
are plausible in the context of nuclear disarmament. In the eyes of those depending
on U.S. extended deterrence for their security, however, Washington’s policy
of not excluding the possibility of first use of nuclear weapons is essential for
the credibility of U.S. extended deterrence. Politically, too, a unilateral change
in the U.S. declaratory strategy in the face of North Korea’s tenacious pursuit
of nuclear weapons and missile development would only encourage Pyongyang. Moreover,
it would be unwise at this time to limit the purpose of retaining nuclear weapons
solely to deter nuclear threats.
It is indeed questionable whether nuclear weapons are suitable to deter the threats
posed by biological or chemical weapons. Nevertheless, it is also true that no assured
means are available for deterring the use of non-nuclear weapons of mass destruction
(WMD) such as biological and chemical weapons. In this strategic dilemma, it is
inadvisable to exclude the possibility, debatable as it might be, that countries
such as North Korea suspected of possessing these WMD would refrain from their use
for fear of being punished with nuclear retaliation.
Contrary to the assertion made by Sagan in his article, I have never “recommended
that the United States should now threaten to retaliate with nuclear weapons if
North Korea uses chemical or biological weapons in any future conflict.” At
the 2009 conference organized by the Carnegie Endowment for International Peace,
I stressed the need for ambiguity in coping with the threats of biological and chemical
weapons, underscoring the distinction between the option of openly rejecting the
use of nuclear weapons in response to a biological or chemical weapons attack and
that of not saying anything about the point, keeping those to be deterred in suspense.
At that conference, I simply noted that “without credible means for deterring
the use of biological and chemical weapons, it would be too early to limit the purpose
of nuclear deterrence solely to deterring the use of nuclear weapons. This is particularly
true for Northeast Asia, where North Korea is suspected to possess both biological
and chemical weapons.”2
It must also be pointed out that the Japanese government’s
pronounced policy of relying on the U.S. nuclear deterrent to protect the country
“against the threat of nuclear weapons” was originally formed as part
of the first Defense Program Outlines adopted in 1976, when the so-called sole purpose
of nuclear weapons was not the question at issue. As I noted in my Carnegie conference
presentation, Tokyo and Washington announced in 2007 that “both nuclear and
non-nuclear strike forces and defense capabilities” of the United States formed
the core of extended deterrence, without specifying the object of this deterrence.
I believe that the planned revision of the official Defense Program Outlines should
reflect this line of thought.
On the other hand, Sagan arguably proposes that “those U.S. allies that remain
concerned about conventional or chemical and biological threats to their security
should . . . help to develop the conventional forces and defensive systems that
could wean themselves away from excessive reliance on U.S. nuclear weapons for extended
Although Sagan’s depiction of the allies’ reliance on U.S. nuclear weapons
as “excessive” is his own, Japan-U.S. defense cooperation has already
been progressing in the direction he suggests. Strengthened cooperation in the deployment
and development of missile defense systems against North Korean missiles is a case
in point. Japan-U.S. defense cooperation will no doubt become increasingly important,
particularly as the role that advanced conventional weapons systems play in the
deterrence strategy is expanded. Japanese efforts to rectify long-recognized deficiencies
in sharing responsibilities under the Japan-U.S. Security Treaty are required more
This leads to the second subject that must be taken into consideration in rethinking
extended deterrence: the level of strategic consultations within alliances. Unlike
NATO, the Japan-U.S. security arrangements lack a mechanism for consultations on
nuclear strategy, as does the South Korea-U.S. alliance, so far as I understand.
The Japanese case is more conspicuous, for the government has long been reluctant
to be involved in U.S. nuclear strategy. The public’s strong anti-nuclear-weapons
sentiment is behind this.
It has therefore been an epoch-making development that the Japanese and U.S. governments
have, since 2009, begun to explore ways to commence consultations on extended deterrence.
As of this writing, though, the alliance has not overcome the unprecedented jolt
caused by the widely reported clumsiness of the new coalition government led by
Prime Minister Yukio Hatoyama of the Democratic Party of Japan in trying to undo
(without proposing any feasible alternative) the long-agreed plan to relocate the
U.S. Marine Corps air station from Futenma, Okinawa—a goal central to the
1996 agreement to reduce burdens on local communities caused by the U.S. force presence
on the island. It is crucial that the two governments, particularly the Japanese,
make every effort to put alliance cooperation back on the right track and pursue
their alleged purpose of “deepening” alliance relations through the
year 2010, which marks the fiftieth anniversary of the current Security Treaty.Closer
consultations on how to facilitate the functioning of U.S. extended deterrence should
be an important part of deeper alliance cooperation.
In the absence of a bilateral agreement on secrecy protection as required by U.S.
law, Tokyo-Washington consultations on nuclear strategy will not reach the level
of NATO’s Nuclear Planning Group. Nevertheless, there are many issues that
the two governments can and must discuss below that level, particularly prospective
changes in the roles of nuclear and non-nuclear weapons in the U.S. deterrence strategy
and, subsequently, required Japan-U.S. defense cooperation for common deterrence
purposes. The declaratory part of the U.S. deterrence strategy should also be an
important agenda item for such consultations.
Another important step is to link Japan-U.S. consultations on extended deterrence
with those between South Korea and the United States. Organizing a trilateral mechanism
for strategic consultations would not be diplomatically advisable, for it might
make China and Russia unnecessarily suspicious and further harden North Korea’s
stance. Given the common interest of Japan and South Korea in enhancing the credibility
of U.S. extended deterrence, though, the time has come for the two countries to
begin to coordinate their efforts to that end, at least through a set of three bilateral
consultations: Japan-U.S., South Korea-U.S., and Japan-South Korea.
Finally, the implications of reductions in U.S. and Russian nuclear stockpiles for
U.S. extended deterrence will have to be assessed carefully, as progress in this
area would eventually affect the nuclear force balance among the United States,
Russia, and China. Russia and China are no longer adversaries of the United States
and its allies. Still, the two countries remain causes for concern, particularly
for U.S. allies in Asia, because of the dictatorial nature of their regimes and
the aggressiveness increasingly seen in their external postures. The continued growth
of China’s military power and its lack of transparency are yet other causes
for concern in the Asia-Pacific region. Moreover, a bilateral nuclear force balance
that Washington would regard as acceptable in relations with Moscow and Beijing
might not be reassuring enough to U.S. allies in Asia in the context of the credibility
of U.S. extended deterrence.
This issue would perhaps not draw attention before U.S. and Russian nuclear stockpiles
each approach the one thousand level. Yet it must be seen as an important subject
for consideration in rethinking extended deterrence between Tokyo and Washington
as well as between Seoul and Washington, and, one hopes, among all three.
1. Remarks by President Barack Obama at Suntory Hall, Tokyo, on November 14, 2009;
2. Panel transcript “Are the Requirements for Extended Deterrence Changing?”
Carnegie Endowment for International Peace, April 6, 2009, http://www.carnegieendowment.org/files/npc_extended_deterrence1.pdf.