In recent years, U.S. officials have grown increasingly fearful of a massive cyberattack, one capable of crippling infrastructure and crashing markets. In 2010, William Lynn, then deputy secretary of defense, wrote in these pages that cyberspace was “just as critical to military operations as land, sea, air, and space.” As defense secretary, Leon Panetta warned of a “cyber–Pearl Harbor.” And in 2013, James Clapper, the director of national intelligence, put cyberattacks at the top of his annual list of transnational threats.
Yet as Washington has poured billions of dollars into shoring up its defenses in the virtual world, it has largely ignored the physical infrastructure that allows cyberspace to exist in the real one. Today, roughly 95 percent of intercontinental communications traffic—e-mails, phone calls, money transfers, and so on—travels not by air or through space but underwater, as rays of light that traverse nearly 300 fiber-optic cables with a combined length of over 600,000 miles. For the most part, these critical lines of communication lack even basic defenses, both on the seabed and at a small number of poorly guarded landing points. And a mounting tally of small-scale breaches points to the potential for large-scale damage.
Washington’s neglect of undersea infrastructure extends beyond cables to an increasingly important source of global oil and gas supply: deep-water drilling. Today, offshore rigs in the Gulf of Mexico account for some 25 percent of total U.S. oil and gas production—a figure the Department of Energy predicts could reach 40 percent by 2040. Outside the United States, global production from deep-water wells has risen from 1.5 million barrels per day in 2000 to over six million barrels per day in 2014. As the infrastructure for offshore drilling grows more sophisticated and widespread, it is also becoming more susceptible to attack, with the potential consequences exceeding those of the giant 2010 oil spill in the Gulf of Mexico.
Although human activities underwater are regulated by numerous international bodies, no single entity has both the authority and the ability to take the