One interesting part of Sea Power: The History and Geopolitics of the World’s Oceans is the idea that the best way to attack a country by sea might be to cut its undersea communications cables:
In 2006 and 2008, accidental destruction of cables effectively shut down Internet services to several large countries or parts thereof, including, among others, Egypt, India, China, and Pakistan. Fortunately, the cables are fairly substantial: typically, a couple of inches thick and well insulated with galvanic padding. But they are quite vulnerable, especially at cable heads when they emerge from the water. In Egypt just a couple of years ago, swimmers were caught while trying to cut through a major 12,500-mile cable. Internet speeds throughout Egypt plummeted by more than 60 percent. Overall, the cable system is fairly robust in facing routine challenges— accidents, anchors dragged over them, corrosion, low-level attacks. The challenge will come as nations and transnational groups (criminal cartels, terrorists) find ways to disrupt them on a massive scale. Even with the 285 cables on the bottom of the world today and the 22 “redundant” or “dark” cables in reserve, the vulnerabilities are clear.
We have 16 $2.7 billion Virginia-class submarines. How could they possibly protect even a single 12,500-mile cable, though? What stops an enemy from building an underwater robot to go down and cut through these vital cables? Instead of investing in another 32 of these submarines should we be building anti-robot robots to patrol up and down the cable paths?