World leaders have to step in to prevent right-wingers in Japan from changing pacifist constitution and making nuclear arms.

The international community should heed the alarm bells that are ringing following the bellicose comments on military buildup, especially nuclear armament, by the leaders of Japan's two main opposition parties.

Liberal Democratic Party leader Shinzo Abe, who according to opinion polls is likely to win Japan's general election scheduled for Dec 16, has been pushing to remove the restrictions of Japan's pacifist constitution and turn the country's Self-Defense Forces into a full-fledged military capable of pre-emptive strikes after making it his party's goal.

Abe established a full defense ministry for the first time since World War II during his short-lived term as prime minister from September 2006 to September 2007, and has long backed proposals that allow the Self-Defense Forces to set foot on foreign land, acquire sensitive facilities and export weapons. Now, he has vowed to "clarify the rights of self-defense, including collective self-defense, and then legislate basic law on national security". And although he has carefully avoided the issue of nuclear weapons during his House of Representatives election campaign, he favors re-activating Japan's nuclear reactors instead of cheaper power from wind and seawaves.

On the other hand, Shintaro Ishihara, who became head of the Japan Restoration Party after it merged with his newly formed Sunshine Party, has had no qualms about being the standard-bearer of a nuclear-armed Japan. On Nov 21, he declared: "It's high time Japan simulated the possession of nuclear weapons."

Simulation is a necessary part of a nuclear-weapons program. After decades of accumulation, Japan already has advanced nuclear technology, enough weapons-grade uranium and plutonium, and abundant teams of experts to design and deploy advanced nuclear weaponry.

Ishihara and other right-wingers have clearly demonstrated the necessary political will, though not yet the authority, to arm Japan with nuclear weapons. Besides, they no longer feel the need to remain quiet about Japan's ability to make nuclear arms "in months or a year".

Japan launched earnest research into nuclear technology in 1954 and now squeezes about 50 reactors in a country no bigger than the US state of New Mexico. It easily acquires plutonium-239, the most useful plutonium isotope for making nuclear weapons, from the spent fuel of these nuclear reactors. Traces of plutonium-239 were found in the soil around the Fukushima Daiichi nuclear power plant after it was devastated by what Ishihara called the "divine punishment" of the earthquake and tsunami in March 2011.

Japan has been developing fast-breeder reactors that produce more fuel than they consume. The plutonium recovered in the process is precisely the kind of isotope needed to make the most effective nuclear weapons, according to nuclear physicist Frank Barnaby, emeritus consultant to Oxford Research Group.

As Ishihara put it, Japan has "a huge pile of plutonium". A report in The New York Times of Nov 28 said Japan's existing plutonium stockpile was 44 tons. And just 3 to 6 kilograms of plutonium is needed to make one nuclear warhead.

Japan is also expanding the use of plutonium dioxide mixed with uranium dioxide, or the much more costly MOX, in its reactors. After straightforward chemical separation, plutonium dioxide could be converted to plutonium, which in turn could be used in nuclear weapons. Japan plans to commission its long-delayed Rokkasho reprocessing plant next year, which produces MOX and could extract as much as 8 tons of weapons-grade plutonium a year.

Apart from upgrading its nuclear technology to the level of the most advanced countries, Japan has also developed sophisticated space programs, advanced electronic equipment and precision-guided technologies, key components in launching medium- and long-range missiles with nuclear warheads.

Japan's political will for peace, typified by former prime minister Eisaku Sato, who from 1964 to 1972 helped seal Japan's Three Non-Nuclear Principles - forbidding the country to produce, possess or allow the entry of nuclear weapons - has been eroded by its political shift to the right.

In 2002, when former chief cabinet secretary Yasuo Fukuda became the most senior Tokyo official to publicly break the taboo on discussing Japan acquiring nuclear weapons, Ishihara said: "Japan can possess nuclear weapons. Go for it!" Ishihara attacked Japan's Non-Nuclear Principles in a 2011 interview, saying that even Sato was "at the same time secretly approaching the United States for help in developing an atomic bomb".

The likes of Ishihara are gradually, but determinedly, dismantling the legal firewalls against Japan possessing nuclear arms and exaggerating the security threat from its neighbors to tilt public opinion in their favor. In March 2011, Ishihara as mayor of Tokyo, instead of supporting a freeze on nuclear facilities, said: "Japan should make nuclear weapons to counter the threat from China" and earn "respect from Russia". He named China, the Democratic People's Republic of Korea and Russia as "our enemies", even though the countries sent aid for the tsunami victims.

Aside from backing right-wingers to land on the Diaoyu Islands, which Japan calls Senkakus, Ishihara proposed in April 2012 to "purchase" the islands, which inflamed the dispute between Beijing and Tokyo and allowed him to exploit the "China threat".

Security is the excuse Japan has been trying to use to break its agreements under the Treaty on the Non-Proliferation of Nuclear Weapons, because under Article X, Japan could withdraw from the treaty if it believes "extraordinary events" jeopardize its "supreme interests".

Japan has already cleared one of the biggest domestic obstacles to making nuclear weapons. On June 20 this year, the Diet ignored protesters and radiation leaks from the Fukushima plant to pass a revision to the peace-oriented Basic Atomic Energy Law enacted in 1955, adding an appendix stating that nuclear power should "contribute to national security". The last legal hurdle on Japan's path to militarism is its pacifist constitution, which has been a constant target of right-wingers and now both Abe and Ishihara.

It seems Japan's domestic laws and the Treaty on the Non-Proliferation of Nuclear Weapons can no longer stop Japan from flexing its military muscles and making nuclear weapons.

The military ambitions and well-orchestrated moves of Abe and Ishihara are unnerving for its neighbors and the rest of the world. Judging from the last war Japan launched but not repented on, its recent calls for pre-emptive strikes and a nuclear arsenal foretell a disaster for humanity. Such an eventuality would not only be a serious challenge to the non-proliferation treaty and the post-World War II international order, but also a threat to peace in the Asia-Pacific region.

So it's time the international community realized the threat from Japanese right-wingers and warmongers and reined in their dangerous designs.

Unfortunately many Western leaders pressuring other countries not to use fissile materials seem complacent about the nuclear ambitions of Japan's right-wingers. France and the United Kingdom have helped Japan extract and store plutonium, and the US has collaborated with it on nuclear technologies and encouraged its military expansion.

These advanced countries should stop Japan from storing and processing plutonium. Leaders of the Western world should join the emerging nations in a fortified resolve to make Japan observe its non-nuclear principles and stick to the road of peace and stability.

Cai Hong is China Daily Tokyo Bureau chief and Wen Zongduo is a journalist with the paper.

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