The nuclear weapons test in North Korea may set off a regional arms race, warns Slate's Fred Kaplan. A new military threat could help Japan's new prime minister revise his country's pacifist constitution and make a push toward nuclear armament. What are the exact limits on Japan's armed forces?
They're not supposed to have any. According to Article 9 of the country's post-World War II constitution—which was drafted by American lawyers—"the Japanese people forever renounce war as a sovereign right of the nation." Furthermore, "land, sea, and air forces, as well as other war potential, will never be maintained."
Article 9 doesn't apply to nuclear weapons. The Japanese government has always maintained the right to develop a defensive stockpile of nukes under the constitution, and the country's Supreme Court would likely go along. But there is an informal policy against the introduction, storage, and use of nuclear weapons. These "three principles" are firmly entrenched, even though they're not codified in the constitution or in any laws.
What about an army? Japan has maintained a pseudo-army—called the "Self-Defense Forces"—for decades, arguing that it's an extension of the national police and therefore doesn't violate the country's constitution. According to Japanese law, the Self-Defense Forces can only be used for, well, "self-defense." Until the last few years, that meant they would defend the islands from enemy attacks. The scope of their mission began to widen after North Korea tested a long-range missile over Japan in 1998.
First, the government signed a deal with the United States to help develop a missile-defense system. A long-standing ban on arms exports was later relaxed so the country could start shipping off missile parts to the Americans. Old-line pacifists say the program has also run afoul of a 1969 law restricting the use of space flight for military purposes, since Japan now has three intelligence satellites in orbit.
Meanwhile, Japanese troops have joined in military operations overseas. The war on terrorism has been deemed exempt from Article 9's specific ban on the "use of force as a means of settling international disputes," since it can be viewed as a form of individual self-defense. Former Prime Minister of Japan Junichiro Koizumi persuaded the parliament to pass temporary laws allowing for overseas deployment. The "Anti-Terrorism Special Measures Law" sent supply ships to help U.S. forces in Afghanistan, and another law from 2003 permitted a limited ground presence in southern Iraq.
More-recent debates have focused on whether the Self-Defense Forces can order emergency missile intercepts without first consulting the prime minister, and if it might be possible to launch a pre-emptive strike under certain conditions. The ruling party has also been considering a rewrite of the constitution that would make it easier for the SDF to deploy overseas. To get such an amendment passed, the government would need a two-thirds majority in both houses of parliament, plus a majority vote in a national referendum. While there's a lot of support for the reforms right now, it looks like the doves still have enough votes to scuttle the plan in one of the houses.
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Explainer thanks Ellis Krauss of the University of California at San Diego.