WELLINGTON, July 6 -- The Pacific island nations that signed the Treaty of Rarotonga in 1986 were not military powers. They had coastlines and fishing fleets and an agreement, ratified eventually by all five of the world's declared nuclear states, that no power would test nuclear weapons in their waters. On Monday at 12:01 p.m., China tested that arrangement.

A People's Liberation Army Navy submarine launched a long-range ballistic missile carrying a dummy warhead into the South Pacific Nuclear Free Zone. China's official Xinhua News Agency confirmed the launch, identifying the vessel as a nuclear-powered submarine and the target as "relevant high seas" of the Pacific. It was Beijing's second Pacific test in two years and only the third ...