New Delhi, June 30 -- "THE SEABED is a battlefield," Australia's defence minister told a room full of admirals and generals in Singapore at the end of May. Richard Marles, citing several subsea cables that have been cut in the Baltic Sea and around Taiwan in recent years, joined 16 of his counterparts in announcing plans to protect the submarine tendrils of the digital world: the nearly 700 communications cables which mostly lie exposed on the floor of the world's oceans.

Governments and armed forces in Asia have only recently awoken to the importance of subsea cables. Some of their fears of subterfuge may be overblown; to date, no conclusive evidence has been shared to suggest that the cuts highlighted by Mr Marles are sabotage. But the...