A specter haunts the great powers of East Asia. It is the specter of ethnic chauvinism and a recrudescent nationalism one would have thought a thing of the past. With this comes the possibility of irrational conflict, and for the entire region the snatching of failure from the very jaws of success. China and Japan have sought a new, post-Cold War equilibrium for 25 years. This is essential and must be accomplished. But now the search takes on a taint of danger only a few of us saw coming. You see this darkening weather across the East China Sea between the mainland and Japan, where the two nations contend for sovereignty over islands, the resources under them, and maritime superiority. You see it as China extends its reach across the South China Sea all the way to Indonesia.