Realigning Priorities: The U.S.-Japan Alliance and the Future of ...

t h e I n s t i t u t e f o r F o r e i g n P o l i c y A n a ly s i s
Deterrence under pressure
For decades, Japan has enjoyed a favorable security balance
or “surplus” in the region, thanks to America’s nuclear
umbrella, U.S. forward-deployed forces, and the absence
of a near peer on the seas or in the skies that could possibly
threaten Japan, apart from perhaps the Soviet Union. The
fact that the Soviet Union was locked in a titanic struggle
with America was oddly comforting to Japan, since Washington’s
deterrence credibility was quite high vis-à-vis such
a stark ideological enemy of relatively minor global economic
consequence. To deal with the security challenges
that did exist, Japan’s favored approach ( for a variety
of legal, political, diplomatic, and budgetary reasons) has
long been external balancing (through the U.S. alliance)
coupled with incremental internal improvements in the
areas of national defense and support for regional and international
operations. Interviews in Japan for this project
revealed concern among defense planners that external
balancing might not be as effective in the future as it has
been in the past.
In the twenty-first century, Japan’s security surplus is
slowly shifting toward a deficit, as North Korea improves
its missile capabilities (potentially mating them with
WMDs and/or targeting both Japanese and U.S. territory).
China’s military modernization is a factor as well, particularly
its investments in “area denial” capabilities (new submarines,
missiles, and aircraft) that are narrowing the gap
in conventional–weapons strength long enjoyed by the allies.
In addition, China is modernizing its strategic nuclear
forces at the same time that the United States is reducing
its nuclear stockpile, likely resulting in a truly viable Chinese
second-strike capability (possibly even nuclear balance
someday).
All of this suggests that the United States and Japan
could lose their nearly exclusive dominance over the conflict
escalation ladder in the region, and some in Tokyo
worry that this will cause Washington to seek to avoid
escalation (outside of theater) at almost any cost. Thus,
questions in Japan about the future of nuclear balance immediately
put the spotlight on the regional conventional
balance, which is still favorable for the alliance but trending
undesirably. This is essentially a Japanese version of
the old Western European fear of “decoupling” during the
Cold War, when some worried that the United States might
detach itself from its strategic commitment to Europe in
the face of a strengthening Soviet Union. The NATO experience
therefore offers lessons that might be useful for the
U.S.-Japan case (and they are explained in this report).
We must be careful not to overstate the degree of Japanese
concern. After all, defense spending in Japan is lower
now than it was in 1996, and policy makers have not moved
away from the country’s “minimum defense” strategy that
relies heavily on U.S. power projection capability and the
U.S. nuclear umbrella. The government still follows the U.S.
debate over nuclear weapons modernization primarily as a
non-proliferation issue, rather than as a domestic security
issue, and officially it won’t let U.S. warships with nuclear
weapons pass through its territorial waters. Japan remains
ambivalent about joining UN- or U.S.-led peace and security
operations overseas with any meaningful force, and it
is only slowly implementing bilateral agreements on U.S.
base realignment in Japan. These are not indicators of a
country overly concerned about imminent regional security
threats or abandonment by its main ally.
Still, Japan has been careful to take incremental steps
to strengthen its defenses and the alliance, by collaborating
on missile defenses, relaxing restrictions on the use of
space for defense purposes, dispatching the Self-Defense
Forces (SDF) abroad on select missions, developing Hyuga-class
helicopter-carrying destroyers, launching its own
network of spy satellites, and agreeing to closer command
and military training relationships with U.S. forces (in addition
to continued host-nation support and payment of a
sizeable portion of costs associated with U.S. base realignment).
The key variable is how potential regional threats
evolve (or don’t) in the future, but Japanese policy makers
are carefully considering their options so as to be ready for
any foreseeable outcome.
For the future, recommendations in Japan for strengthening
deterrence generally fall within four basic categories:
1) greater security independence from the United States;
2) support for the alliance but hedge actively against the
potential for U.S. abandonment (hedging for substance);
3) support for hedging, but primarily as a means to deter
abandonment (hedging for show); and 4) greater military
cooperation with the United States as a way to avoid
abandonment (the “indispensable ally” argument). Under
Prime Minister Koizumi especially, the fourth approach
held sway, but there have been some security policy choices
that also drift into the second and third categories (some
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The U.S.-Japan Alliance and the Future of Extended Deterrence