Attacks on NATO’s governments and their citizens are more likely these days to come in the form of electronic malware through fiber optic cables, or improvised explosive devices in mass transportation systems, or extreme weather conditions disrupting critical energy grids and infrastructure than in the form of tanks and infantry columns crossing NATO’s borders… The new security challenges will increasingly test NATO’s posture and readiness, whether it is prepared and willing or not. These new threats are good at identifying and exploiting vulnerabilities and they adapt and reorganize very quickly. In the future, no defense will work statically for decades on end as nuclear deterrence and flexible response worked for NATO during the Cold War years. The future belongs to the agile, not to the stolid.