Welcome to the G-Zero era, a world of every nation for itself. The United States will remain the sole superpower for the foreseeable future, but war-weary, under-employed, debt-plagued voters will reject an activist foreign policy. Europeans won‘t fill the vacuum; they‘re busy fighting over how best to save the eurozone. China and other emerging powers won‘t be much help. They face too many complex challenges at home to accept new risks and burdens abroad.