Japan Times has the story, noting that the Japanese constitution forbids the country from taking part in collective defense. Granted, since the early Fifties, the Japanese constitution's declaration that Japan had forever renounced its warmaking power has been gradually whittled away, to the point that Japan's military is formidable as a regional power, at least on paper.

And the Japanese government's policy declaration probably doesn't mean all that much in practice. Japan Times notes that even though the Government's interpretation of the constitution doesn't allow the Self-Defence Force to shoot down missiles aimed at non-Japanese possessions, the government has hedged its position, stating that "in cases where the precise destination of a missile cannot be predicted, it will consider the probability of [the missile] targeting Japan as high and consider it an armed attack on Japan, allowing interception." I suspect that this is little more than a legal fig leaf, similar to the Japanese government's more-or-less acquiesence in the American government's use of Japanese islands as part of U.S. nuclear warfighting plans, despite the country's official status as a non-nuclear nation.

Still, the official line is a minor setback for the Bush administration's love affair with the son of Star Wars. Yahoo! News has a great collection of recent articles on missile defense, detailing, among other events, the continuing failures of NMD testing and Washington's continuing inability to get Canada to sign on to missile defense. Since the Japanese and the U.S. are partners in researching and building one form of an anti-missile shield, the news that Tokyo can't officially commit to defending its ally is unfortunate.