The Brookings Institute hosted a discussion on cyber deterrence featuring Ralph Langner and Dmitri Alperovitch. From the website:
Langner argues that deterrence is unlikely to prevent intense cyberwar and cyberterrorist attacks because they can be carried out by small international teams and prepared months or years in advance. He also points out cyberattacks against critical infrastructure and terrorist targets such as chemical facilities and nuclear power plants can and must be prevented by solid cyber protection. Alperovitch, on the other hand, presents a case for a strategic declaratory deterrence policy to counter highly destructive cyberthreats from nation-state actors against critical infrastructure and other crucial national security and economic assets.
You can listen to a podcast of the event here.