According to recent reports, some Japanese officials are attracted by the idea of an alignment with India against China. India, they say, occupies an important position astride Japan's sea routes to the Persian Gulf. They note that India is the world's largest democracy, so Japan can work with it on matters of common interest. And, they say, India's growing middle class and high-tech companies are attractive for Japan. Some scope may exist for limited Japanese defense cooperation with India. But it's folly to think that the enemy of my enemy is necessarily my friend. The risks of alignment with India outweigh the advantages.

Japan is feeling growing Chinese strategic pressure on its sea lanes, vital for its energy imports from the Middle East. It is disturbed by China's attempts to intimidate Taiwan, an island just south of Japan. But in the Indian Ocean, India has its own ambitions that could one day threaten Japan's sea routes. For decades, India has hatched arms-control schemes in the Indian Ocean targeted at the island of Diego Garcia, vital for U.S. strategy in the Gulf. Because of Japan's need for maritime security, Diego Garcia is as strategically important for Japan as islands that are much closer to home, such as Taiwan. India, if it were able to plant its foot on Japan's jugular in the Indian Ocean, would be tempted to apply pressure.

If it aligned with India, Japan would risk entanglement in the messy religious-based hostilities of the subcontinent, including Kashmir. An India-Japan alignment would also help push Pakistan further into the arms of Beijing, and fuel tensions among the two nuclear-armed states of the subcontinent, which have already fought three wars.