This report looks at the political-military aspects of cybersecurity and attempts to place it in the larger context of international security. Networks are embedded in our economies and our political and social life. They have become the central tool for human activity. These networks form cyberspace. They hold information of immense value, and they control the machinery that provides critical services. They create immense economic benefit, but they are also a major source of risk to nations. Governments have been hesitant to interfere with the golden economic machine, and the result is a weakly governed space, much like a failed state or contested terrain. Cybersecurity has been an issue for national security since the 1990s, but the U.S. response has been ad hoc and reactive, marked by uncertainty over how to deal with a major new problem for international security. This report identifies six principles that should guide the United States in developing a strategic approach to cybersecurity.