Last March, in an interview with The New York Times, U.S. presidential candidate Donald Trump suggested it might not be a “bad thing” if Japan and South Korea developed nuclear weapons.

Really? In my view, this was a reckless suggestion, like so much else that Trump has proposed. He presents half-baked ideas while ignoring the negative consequences and sound advice on whatever subject he happens to be ricocheting off at the time.

Since becoming president, Trump hasn’t broached the subject, but conservative pundit Charles Krauthammer thinks that North Korean actions warrant Japan playing the nuclear card.

Going nuclear, however, won’t make Japan safer and won’t lighten the American security burden. Corey Wallace, a postdoctoral researcher at the Free University in Berlin, notes, “It all comes down to whether whatever option Japan chooses would actually buy more deterrence than it does provoke others to implement more aggressive military postures or actions.”

Alessio Patalano, a senior lecturer in war studies at King’s College London, points out: “Northeast Asia remains the single most nuclearized region in the world. This leaves the ROK and Japan in a difficult position if nuclear deterrence is not guaranteed by the alliance with the United States.”

As Wallace explains, “Over the years Japanese policymakers have analyzed this issue and have concluded that Japan having its own weapons would not necessarily buy the deterrent effect needed, and have taken the option off the table.” Such an assessment might change if Japanese analysts conclude that national survival is at stake, involving scenarios such as an invasion of the Japanese mainland or a military blockade.

Patalano doesn’t believe “that developing nuclear weapons is currently a better option for Japanese security than the umbrella offered by the United States. On the other hand,” he says, “it depends on the cost that the United States intends to impose for Japan to retain the current situation.”

Wallace suggests that “the most likely justification for acquiring them is as a second-strike capability to deter such a nuclear first strike, or more realistically, to prevent nuclear coercion.” Yet, he says, “here the problem is whether Japan can realistically implement a survivable and credible second-strike posture that would actually deter more than it provokes.”

Japan’s most likely option would be a second-strike capability centered on submarine-launched ballistic missiles.

“Japan possesses already a good submarine force and, in principle, acquiring boats for the launch of nuclear missiles is not impossible,” Patalano says. “But the costs to maintain such a force and to develop it in a way to be an effective deterrent are, as the British experience proves, very high and demand a depth in the political debate that is currently absent.” A 2016 Genron poll found only 5 percent of Japanese support their nation possessing nuclear arms.

“Japan could produce a handful of rudimentary nuclear devices in probably a matter of months,” Wallace believes, but “the question then becomes whether the others would allow Japan to go about implementing such capabilities. One assumes that tensions would have to be quite significant for Japan to consider this option — and precisely because they are high, others may not sit quietly.”

China would surely not accept reassurances that the nuclear weapons were only to counter the North Korean threat.

Overall, Wallace argues, “the escalation dynamics surrounding Japan implementing a nuclear posture are not in Japan’s favor, and I expect that Japan will remain entrenched within the framework of U.S. extended deterrence.”

It is also problematic that Japan going nuclear independently would be the death knell for the Nuclear Non-Proliferation Treaty system, “meaning a whole range of other nations, including unstable ones, may end up acquiring their own arsenals,” Wallace adds.

Robert Jacobs, a professor at Hiroshima City University’s Peace Institute, also thinks that playing the nuclear card would be counterproductive, arguing that “no country is safer with nuclear weapons.” Nuclear weapons also carry wider implications in terms of committing Japan “to maintaining nuclear technologies (in part to produce weapons) that radically increase the amount of high-level and long-term nuclear waste they eventuate.” This, Jacobs says, “will plague these societies for millennia.”

Nuclear waste storage is already a growing problem for countries operating reactors, but Jacobs warns that “countries with military nuclear production face far larger and more intractable ecological disasters than those with only nuclear power.”

Jacobs asserts that the government is now promoting the use of MOX fuel — the mixed-oxide type developed from plutoniium and uranium — in nuclear reactors, even though it is one of the priciest options and not cost-effective, because this deflects international concerns about Japan’s large plutonium stockpile. In his view, the government maintains this stockpile partly to retain the nuclear weapon option.

On Jan. 24, the Sasakawa Peace Foundation’s Daniel Bob posted a compelling essay on the website 38 North about why encouraging Japan to play the nuclear card would not advance denuclearization of North Korea. Using “the threat of Japan going nuclear to compel China to force North Korea to give up its nuclear weapons would almost certainly fail,” he says — and reinforce “North Korea’s determination to keep its nuclear weapons as the key to its survival.” Moreover, Bob argues, there is no pressing need for such arms.

“Large numbers of American troops in both Japan and South Korea reinforce the U.S. commitment that an attack on either country would meet the same response as an attack on the United States. Theater missile defenses in Northeast Asia, the U.S. national missile defense system and an American nuclear arsenal that dwarfs that of North Korea provide further surety against the DPRK threat,” Bob says. “The proliferation of nuclear weapons would not only increase the chance of catastrophic war in the context of regional tensions, but also of loose nukes falling into the wrong hands.”

Patalano concludes: “A more viable alternative would be for Japan to focus on developing missile defense to make it operational at the earliest convenience, reinforce its Aegis destroyers component so as to have regular patrols for missile defense, and complement that with conventional striking capabilities to reduce the possibility of a first use. Such an option,” he says, “whilst still controversial, would be both financially and technically more feasible than any other course of action.”

Jeff Kingston is the director of Asian Studies, Temple University Japan.

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