China is busy pouring silt and building bases onto man-made islands in the South China Sea. Russia is launching newer, faster, quieter nuclear submarines. Iran is making noises about closing the Strait of Hormuz to U.S. shipping.

Throw in cyberattacks, piracy, smuggling of drugs, guns and people, and new technologies that are eroding America’s traditional maritime superiority, and there is no lack of threats for the chief of naval operations to worry about.