For 70 years, the thinking inside the Pentagon was that only nations with nuclear weapons could threaten America’s existence. But that assumption is now in doubt: in a world in which almost everything is interconnected – phones, cars, electrical grids, and satellites – everything can be disrupted, if not destroyed. In THE PERFECT WEAPON, Belfer Center Senior Fellow and Adjunct Lecturer in Public Policy David Sanger, the New York Times national security correspondent, details how this new revolution, being conducted largely in secret, is reshaping global power.

Reversing a trend toward cutting nuclear stockpiles that dates to the early ’90s, a recent Pentagon report called for ramping up U.S. reliance on nuclear weapons in order to keep pace with an aggressive arms buildup by Russia. Complicating matters, Russian President Vladimir Putin boasted today of having new weapons that could evade U.S. defense systems, taunting that their sophistication would force America to “listen to us now.”