Futurists who applaud Obama for gutting conventional forces—ships, planes, and boots on the ground—and (allegedly) shifting to emerging, asymmetrical, or hybrid threats (pick your adjective of the week) ought to think again. The distinctions with how our military will have to deal with challenges like cyberconflict and shooting wars are not as disparate as they seem.

Cyberspace is a loaded and misleading term. There is no Wild West where electrons roam freely. Every thought expressed on the Internet eventually has to be fed into a transmission system or device, and when that happens, cyberspace and the physical domain become one—and cyberstuff becomes as vulnerable to bombs, bullets, and other offensive acts as any other target in warfare.

Nine countries recently got a small object lesson in the crossover between cyberwarfare and real warfare. Most of the world’s Internet traffic is routed through undersea cables. A pair of accidents at sea inadvertently cut the East African Marine Systems fiber-optic cable, setting off widespread telecom outages.

This time it was accident. Next time, it might be war—and it has happened before. One of Britain’s first acts of war in World War I was to cut Germany’s transatlantic cables and take out their wireless stations around the world—essentially taking out the Kaiser’s capacity to communicate around the world.

Protecting undersea infrastructure, as well as freedom of the seas, is a key military responsibility. To protect the U.S. flag wherever it flies, America should be able to operate with confidence in the physical domains as well as the cyberworld. Having one set of capabilities without the other is like having a car with tires or an engine—but not both.