Any current analysis is likely to fade away with time, the way children's sandcastles do when the tide rises, leaving behind their vague shapes. New episodes eclipse the old, and they are treated as novel problems, not merely new examples of familiar unsolved issues.

The three areas discussed in this book will remain relevant even after a new administration is in charge of the country and after the past dozen years of war have become a distant memory. Different versions of similar problems will plague government agencies. Insurgencies with different names and faces will challenge governments and terrorize civilians. America or Europe might well suffer a crippling cyber attack.

Yet, as difficult and enduring as the problems discussed in this book may be, they are not impervious to ingenuity. The United States has always been an innovative, problem-solving nation, and those skills are sorely needed now to deal with the gray space between war and peace. Other rising nations will also show resilience and find imaginative approaches.

Counterinsurgency,

Counterinsurgency in the form laid out in the U.S. Army/Marine Corps Counterinsurgency Field Manual may not be repeated for a decade or more, after its unfulfilled promises in both Iraq and Afghanistan. Moreover, the pattern of retreat into national isolationism after a period of aggressive military effort is well established. But when the international community becomes engaged in asymmetric ground warfare once again, we should finally recognize that supporting governments that cannot gain the trust of their people is a poor investment. Why were we surprised by ISIS gains when the United States had accepted the al-Maliki government's exclusion of Sunnis from all forms of political and economic advancement in Iraq? Surely we could have predicted Taliban gains in Afghanistan when police and the courts routinely demanded bribes and two elections were fraught with corruption. In each case there were democratic alternatives.