Can Japan Continue to Live in the Nuclear Neighborhood Without Its Own Nuclear Weapons?


2012-10-08 by Richard Weitz

The North Korean nuclear threat and the growing power of China in the region – with a solid growth in nuclear weapons as well – provides a continual test for the U.S. nuclear guarantee for Japan.

Thus far, the situation in Korea has not resulted in a crisis of confidence over the credibility of U.S. security guarantees or other major harm to the Japanese-American alliance. If anything, Japan-U.S. ties have become stronger during the last decade despite Japan’s continuous redefinition of its foreign and defense policies.

Although North Korea’s October 2006 nuclear weapons test prompted an unprecedented public debate in Japan about whether to develop an independent nuclear deterrent, continued confidence in U.S. pledges to defend Japan against external threats has thus far averted a change in the long-standing policy of nuclear abstention.

Shortly after the test, U.S. Secretary of State Condoleezza Rice flew to Tokyo to reaffirm the U.S. government’s “firm commitment” to uphold its bilateral security guarantees, including the nuclear deterrent pledges embodied in the 1960 Mutual Defense Treaty, in one of the most direct statements in years.

Persistent faith in the credibility of American security guarantees has also reassured Japan’s national security decision makers about relying on the U.S. Air Force and the U.S. Navy for power projection capabilities rather than developing their own aircraft carriers, strategic bombers, or long-range missiles.

Whatever the possible value in preemptively destroying DPRK missiles aimed at Japan, the SDF’s acquisition of such “offensive” weapons systems would deepen concerns in South Korea and China about Japan’s military ambitions.

Japan Has Options

Japan probably has the scientific, economic, and technological infrastructure to develop a nuclear arsenal should its government decide to do so. The country possesses a large and very advanced civilian nuclear power industry that would allow it to construct nuclear explosive devices without much difficulty.

A secret study that Japan conducted in 1967 concluded that the country could produce an atomic bomb by extracting plutonium from its civilian nuclear power plants. Japan’s nuclear energy program, the world’s third largest in terms of power output, has generated an enormous surplus of separated reactor-grade plutonium, sufficient to manufacture hundreds of nuclear weapons. The Japanese could also produce weapons-grade plutonium or weapons-grade uranium through standard enrichment techniques.

In addition, Japanese scientists would not find it difficult to develop reliable nuclear warheads even without testing them. They have extensive experience and capabilities with nuclear materials and supercomputing.

Furthermore, Japanese petroleum engineers have developed complex detonation devices to extract oil. Japanese technical experts have had to study nuclear weapons design issues in order to assess the nuclear weapons programs of China and North Korea.

Will the United States and its allies shape a credibility defense strategy in the Pacific to reduce the nuclear threat? Or will growing threats to Japan lead Japan to join the nuclear club? Credit Image: Bigstock 

Finally, Japan could draw on its civilian space launch program to develop long-range ballistic missiles.

Japanese space rockets have launched a number of commercial, research, and recently reconnaissance satellites (which could assist with target selection). Several of these launchers could serve as the basis for nuclear-armed ICBMs. Common estimates project that Japan could test a nuclear device in less than a year—and that it would not require much additional time to develop a comprehensive nuclear arsenal, which would include nuclear delivery vehicles (e.g., ballistic missiles or warplanes) as well as an adequate command-and-control infrastructure.

The growing nuclear threat from the DPRK, the rising power of the PRC, and the Obama administration’s policy of generally de-emphasizing the role of nuclear weapons in world politics has led some Japanese security experts to question the credibility of U.S. extended security guarantees to defend Japan from external threats by whatever means necessary.

The backbone of these security guarantees, manifested most visibly in the deployment of sizeable U.S. conventional forces in Japan as well as the bilateral mutual defense treaty between Tokyo and Washington, is the U.S. commitment to defend Japan with nuclear weapons if necessary.

Will They Exercise Them?

If Japanese lose faith in the U.S. willingness or capacity to defend them, or they come to fear that potential foreign aggressors doubt the credibility of U.S. assurances, then they might pursue alternative security policies, including possibly seeking their own nuclear weapons, to increase their ability to deter external threats.

Wikileaks earlier published a State Department cable from November 2008 that reported official Japanese concerns about the reliability of U.S. extended nuclear security guarantees “given the deteriorating nuclear situation around Japan, as North Korea continues to develop capabilities and China expands its arsenal.” The cable related that, “There are some in Japan that are discussing indigenous nuclear development in Japan, partly due to a lack of confidence in the U.S. extended deterrence.”

Despite Japan’s latent nuclear capacity and the perceived worsening of its security environment, Japanese leaders have until now refrained from developing nuclear weapons.

Confidence in American pledges to defend Japan against external threats—even with U.S. nuclear weapons if necessary—has provided the main reason why Japanese policymakers have continued their policy of nuclear weapons abstention.

But for these pledges to remain credible, the United States needs a solid conventional defense capability along with its allies in dealing with the ascendant power in the neighborhood – China.

If such credibility is called into question, and with a trajectory towards further reductions in nuclear weapons in the United States, processes could well be set in motion which would pressure for change in Japanese policies.

Japanese leaders continue to express confidence in the U.S. nuclear umbrella that lies at the core of the mutual defense treaty. The continued deployment of substantial U.S. military forces on Japanese territory reinforces the credibility of this guarantee.

Like previous U.S. governments, the Obama administration has managed to limit Tokyo’s interest in developing nuclear weapons by underscoring the U.S. will and ability to help Japan counter external threats. For example, the administration has continued to develop the F-35 and has backed Tokyo’s decision to purchase the plane as its next main front-line fighter.

Japanese policy makers have strengthened their national defenses in response to external threats, but have thus far refrained from seeking an independent nuclear weapons arsenal or radically increasing defense spending to develop a substantially more powerful conventional force.

They continue to rely on their security alliance with the United States to provide these capabilities — persisting in their post-World War II practice of prioritizing defense ties with Washington above all other considerations in determining national security policy.

And it is not just about the United States.  The ability of the allies in the Pacific to work more effectively together to provide for conventional deterrence is a key element as well.

But like much in life, this is a bet. And pressure will grow on this bet as the security pressures unfold in the 21st century and the U.S. works through with its allies a new Pacific strategy.